Effects of a Single Bout of Aerobic Exercise Versus Resistance Training on Cognitive Vulnerabilities for Anxiety Disorders.

This article was downloaded by: [University Library Utrecht] On: 23 April 2015, At: 12:33 Publisher: Routledge Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK

Cognitive Behaviour Therapy Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/sbeh20

Effects of a Single Bout of Aerobic Exercise Versus Resistance Training on Cognitive Vulnerabilities for Anxiety Disorders a

a

b

Joshua J. Broman-Fulks , Kerry Kelso & Laci Zawilinski a

Department of Psychology, Appalachian State University, Boone, NC, USA b

Department of Psychology, University of Southern Mississippi, Hattiesburg, MS, USA Published online: 19 Mar 2015.

Click for updates To cite this article: Joshua J. Broman-Fulks, Kerry Kelso & Laci Zawilinski (2015): Effects of a Single Bout of Aerobic Exercise Versus Resistance Training on Cognitive Vulnerabilities for Anxiety Disorders, Cognitive Behaviour Therapy, DOI: 10.1080/16506073.2015.1020448 To link to this article: http://dx.doi.org/10.1080/16506073.2015.1020448

PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms

Downloaded by [University Library Utrecht] at 12:33 23 April 2015

& Conditions of access and use can be found at http://www.tandfonline.com/page/ terms-and-conditions

Cognitive Behaviour Therapy, 2015 http://dx.doi.org/10.1080/16506073.2015.1020448

Effects of a Single Bout of Aerobic Exercise Versus Resistance Training on Cognitive Vulnerabilities for Anxiety Disorders Joshua J. Broman-Fulks1, Kerry Kelso1 and Laci Zawilinski2 Department of Psychology, Appalachian State University, Boone, NC, USA; 2Department of Psychology, University of Southern Mississippi, Hattiesburg, MS, USA


1

Abstract. The purpose of this study was to compare the relative effects of a single bout of aerobic exercise versus resistance training on cognitive vulnerabilities for anxiety disorders. Seventy-seven participants (60% female; 84% Caucasian) were randomized to complete 20 min of moderateintensity aerobic exercise, resistance training, or rest, followed by a 35% CO2/65% O2 inhalation challenge task. Results indicated that aerobic exercise and resistance training were significantly and equally effective in reducing anxiety sensitivity (AS) compared with rest (h2p ¼ :52), though only aerobic exercise significantly attenuated reactivity to the CO2 challenge task. Neither form of exercise generated observable effects on distress tolerance, discomfort intolerance, or state anxiety (all ps . .10). The results of this study are discussed with regard to their implications for the use of exercise interventions for anxiety and related forms of psychopathology, and potential directions for future research are discussed. Key words: exercise; anxiety; carbon dioxide; distress; discomfort; tolerance. Received 31 January 2015; Accepted 14 February 2015 Correspondence address: Joshua J. Broman-Fulks, PhD, Department of Psychology, Appalachian State University, 222 Joyce Lawrence Lane, Boone, NC28608, USA. Tel: 828-262-2272. Fax: 828-262-2974. Email: [email protected]

Anxiety disorders are among the most prevalent forms of mental illness, affecting nearly 30% of the population (Kessler et al., 2005) and costing the United States alone more than $42 billion annually (NIMH, 2001). Pharmacotherapy and cognitive-behavioral therapy (CBT) have demonstrated efficacy in the treatment of anxiety disorders (e.g., Hoffman & Smits, 2008), though each is associated with a unique set of treatment barriers (e.g., side effects and relapse after discontinuation of medication, high financial costs, low availability of competent providers, stigma), resulting in fewer than 15% of anxious individuals ever receiving even “minimally adequate treatment” (Mohr et al., 2010; Wang et al., 2005). Thus, there has been a recent push to find ways to improve client access to efficacious anxiety treatments. Accumulating research indicates that physical exercise may be a highly effective form of intervention for anxiety and related disorders q 2015 Swedish Association for Behaviour Therapy

(see Asmundson et al., 2013). Exercise interventions have been shown to generate significant reductions on broad anxiety measures and disorder-specific symptoms among individuals experiencing panic disorder (Broocks et al., 1998), posttraumatic stress disorder (PTSD) (Manger & Motta, 2005), obsessive – compulsive disorder (Brown et al., 2007), and generalized anxiety disorder (Herring, Jacob, Suveg, Dishman, & O’Connor, 2012). Preliminary research even suggests that exercise may be as effective as traditional CBT in treating anxiety (Fremont & Craighead, 1987), and exercise significantly enhances the effectiveness of CBT (Gaudlitz, Plaq, Dimeo, & Strohle, 2015; Merom et al., 2008). Although a variety of psychological and biologically based mechanisms have been proposed to account for in the anxiolytic effects of exercise (see Asmundson et al., 2013), one area that has received increasing attention in recent years is the potential impact of exercise on risk factors for


2

Broman-Fulks, Kelso, and Zawilinski

the development and perpetuation of anxiety disorders. Anxiety sensitivity (AS), or the fear of anxiety-related sensations, and fearful responding to carbon dioxide (CO2) inhalation are two cognitive individual difference variables that exhibit unique and interactive predictive power in the etiology and maintenance of anxiety pathology (Reiss, 1991; Schmidt, Lerew, & Jackson, 1997; Schmidt, Maner, & Zvolensky, 2007; Schmidt & Zvolensky, 2007; Schmidt, Zvolensky, & Maner, 2006). Research suggests that repeated exposure to anxiety-related sensations using CBT or other methods of exposure reduce AS and CO2 reactivity, and result in concomitant improvements in psychological functioning and reduced risk for subsequent development of Axis I disorders (e.g., Gallagher et al., 2013; Schmidt, Trakowski, & Staab, 1997). Consistent with exposure therapy models of anxiety treatment, researchers have suggested that physical exercise represents a form of interoceptive exposure for individuals with high AS and fearful responding to CO2, and several studies have indicated that regular aerobic exercise generates significant and lasting reductions in AS and CO2 reactivity, with effect sizes being large and observable in as little as one session (BromanFulks, Berman, Rabian, & Webster, 2004; Broman-Fulks & Storey, 2008; Smits et al., 2008; Stro¨hle et al., 2009). Although the effects of aerobic exercise on AS and CO2 reactivity are well documented, relatively little is known regarding the effects of physical exercise on other anxiety vulnerability factors, such as distress tolerance (DT) and discomfort intolerance (DI). DT refers to the ability to tolerate broad negative emotional states (i.e., feelings of “distress” or “upset”; Simons & Gaher, 2005), whereas DI reflects tolerance of uncomfortable physical sensations (Schmidt, Richey, Timpano, & Buckner, 2007). Low DT and high DI are hypothesized to increase susceptibility to anxiety-related problems via perceptions that anxiety and associated physical sensations are overwhelming or uncontrollable. Psychometric research suggests that DT and DI exhibit unique predictive ability for anxiety symptoms and fearful responding to CO2 above and beyond variance accounted for by AS, and AS and DI demonstrate an interactive effect on CO2 responding (e.g., Keough,

COGNITIVE BEHAVIOUR THERAPY

Riccardi, Timpano, Mitchell, & Schmidt, 2010; Schmidt, Richey, et al., 2007). Despite the significant conceptual overlap among AS, DT, and DI and the potential that exercise may serve as a form of exposure for DT and DI, researchers have yet to examine the effects of physical exercise on DT and DI. Although aerobic exercise has been the predominate mode of exercise utilized in anxiety treatment research, other forms of exercise, such as resistance training, also hold promise as interventions for anxiety and vulnerability factors. Results of the few randomized controlled studies conducted to date suggest that resistance training exhibits anxiolytic properties (see O’Connor, Herring, & Caravalho, 2010 for a review), though direct comparisons of aerobic exercise and resistance training have yielded mixed results. Although some studies suggest that a single bout of aerobic exercise is more effective at reducing state anxiety than resistance exercise (e.g., Raglin, Turner, & Eksten, 1993), others indicate that regular aerobic exercise and resistance training exhibit comparable anxiolytic effects (e.g., Hale & Raglin, 2002; Herring et al., 2012). From a theoretical perspective, there is reason to believe that aerobic exercise and resistance training may differentially affect anxiety vulnerability factors. Aerobic exercise elicits prolonged physiological arousal for the duration of the exercise, whereas resistance training generally involves repeated bursts of physical exertion followed by periods of rest. Traditional theoretical accounts of exposure therapy have commonly maintained that exposures should be delivered in a prolonged, continuous manner to achieve maximum efficacy (e.g., Foa & Kozak, 1986; Marshall, 1985). However, some research indicates that brief doses of exposure (e.g., 30 s or less) may be just as effective as prolonged exposure in reducing anxiety outcomes and may even have some distinct advantages in that brief exposures are less aversive to complete and may produce fewer avoidance behaviors in session (Seim, Waller, & Spates, 2010). Thus, given differences in patterns of exposures, it is important to determine whether aerobic exercise and resistance training exhibit differential effects on anxiety vulnerabilities. The purpose of this study was to provide the first direct comparison of the effects of aerobic

2015

Effects of Exercise on Anxiety Vulnerability


exercise and resistance training on AS and CO2 reactivity. In addition, this study represents the first evaluation of the effects of either aerobic exercise or resistance training on other known anxiety vulnerability factors, particularly DT and DI. Based on previous research, it was hypothesized that participants who completed a single session of aerobic exercise or resistance training would report greater decreases in AS, CO2 reactivity, DT, DI, and state anxiety relative to non-exercising controls. No differences were anticipated between aerobic exercise and resistance training on any of the outcome measures.

Methods Participants As seen in Figure 1, 270 prospective participants were screened to obtain the final sample of 77 participants who met inclusion criteria and agreed to participate. To qualify for the study, participants had to be in good physical health and not involved in a regular exercise program (i.e., exercising , twice per week). The final sample was predominately female (60%) and Caucasian (85%) (See Table 1 for a demographic breakdown by condition).

Informed consent was obtained from participants, and the consent process and research protocol were approved by the Institutional Review Board at Appalachian State University.

Measures AS Index – 3. The Anxiety Sensitivity Index-3 (ASI-3) is an 18-item self-report measure designed to assess fear of anxiety sensations. Items are rated on a 5-point Likert-type scale (0 ¼ very little to 4 ¼ very much). Initial evaluation of the ASI-3 has indicated that it possesses sound psychometric properties, including good alpha scores (ranging from .78 to .91 in North American samples) and excellent convergent, discriminant, and criterion-related validity (Taylor et al., 2007). Cronbach’s alpha in the present sample was .87. Acute Panic Inventory. The Acute Panic Inventory (API) consists of 17 items that assess the presence of current panic-related symptomology using a 4-point Likert scale (0 ¼ not present to 3 ¼ severe). The API has been used extensively in panic and biological challenge task research and possesses adequate psychometric properties

Assessed for eligibility (n = 270) Excluded (n = 193) -Exercising > 1x/week (n = 156) -PAR-Q ineligible (n = 4) -Not interested (n = 33)

Randomized (n = 77)

Allocated to aerobic (n = 25)

Allocated to resistance training (n = 26)

Allocated to control (n = 26)

Completed aerobic exercise (n = 25)

Completedresistance training (n = 26)

Completed control (n = 26)

Figure 1. Participant flow.

3

4



Table 1. Demographic characteristics and baseline measures for aerobic exercise, resistance training, and rest conditions Aerobic exercise (n ¼ 25)


n (%)

M

SD

Resistance training (n ¼ 26) n (%)

M

SD

Rest (n ¼ 26) n (%)

M

SD

Age 20.12 2.64 19.19 2.00 19.74 1.72 Gender Male 9 (36%) 10 (38%) 12 (46%) Female 16 (64%) 16 (62%) 14 (54%) Race Caucasian 22 (88%) 23 (88%) 20 (77%) African-American 2 (8%) 2 (8 %) 3 (11%) Hispanic/Latino 0 0 1 (4%) Asian 0 0 1 (4%) Other 1 (4%) 1 (4%) 1 (4%) Baseline ASI-3 scores 10.92 6.47 9.77 7.28 10.23 8.62 Baseline API scores 3.16 3.39 3.27 3.35 3.19 4.60 Mean resting HR 78.92 9.71 76.19 12.70 81.19 13.40 Mean exercise/rest HR* 145.38 12.43 116.28 25.25 75.99 26.11 Mean HR between RT sets 94.33 13.20 Note. HR, heart rate; RT, resistance training. The groups did not differ on any demographic variables. *p , .001.

(Liebowitz, Gorman, Fyer, Dillon, & Klein, 1984). Cronbach’s alpha in the present sample was .82. Distress Tolerance Scale. The Distress Tolerance Scale (DTS) is a 15-item self-report questionnaire designed to assess individual differences in the ability to withstand aversive emotional states. Items are rated on a 5-point Likert-type scale (1 ¼ strongly agree to 5 ¼ strongly disagree). Initial evaluation of the DTS indicates that it has sound psychometric properties with good convergent, discriminant, and criterion validity and an alpha of .89 (Simons & Gaher, 2005). Cronbach’s alpha in the present sample was .93. Discomfort Intolerance Scale. The Discomfort Intolerance Scale (DIS) is a 5-item self-report measure of tolerance and avoidance of discomfort sensations. Items are rated on a 7-point Likert-type scale (0 ¼ not at all like me to 6 ¼ extremely like me). The DIS subscales exhibited good to adequate internal consistency in the present sample, with the Intolerance subscale exhibiting an alpha of .94 and the Avoidance of Physical Discomfort subscale demonstrating and alpha of .65, which is consistent with alphas reported in previous research (Schmidt, Richey, & Fitzpatrick, 2006; Schmidt, Richey et al., 2007).

State-Trait Anxiety Inventory-State Subscale. The State-Trait Anxiety Inventory-State Subscale (STAI-S) is a 20-item self-report measure used to assess current anxious mood. Items are rated on a 4-point Likert scale (1 ¼ not at all to 4 ¼ very much so). The STAI-S possesses high internal consistency coefficients (ranging from .86 to .95) and good convergent and discriminant validity (Spielberger, Gorsuch, Lushene, & Jacobs, 1983). Cronbach’s alpha in this study was .87. Physical Activity Readiness Questionnaire. The Physical Activity Readiness Questionnaire (PAR-Q) is a 7-item screening test designed to identify individuals at risk for complications when initiating an exercise program. If any question is answered “yes,” a medical examination by a physician is recommended before participation in the exercise program. The PAR-Q has demonstrated strong sensitivity and specificity and has been used in dozens of exercise studies (e.g., Cardinal, Esters, & Cardinal, 1996).

Procedures Participants were randomly assigned to aerobic exercise, resistance training, or rest. Upon reporting to the lab, which consisted of a waiting area, a weight training room


2015

containing a large circuit trainer and free weights, and an aerobic exercise room containing a treadmill, participants completed the informed consent process and height, weight, and current age assessed. Participants were fitted with a Polar heart monitor, which they wore the remainder of the session, and administered a series of questionnaires. Baseline heart rate (HR) was assessed after participants had been seated for 5 min. Aerobic exercise. Participants in the aerobic condition completed a directed stretching procedure followed by 2 min of slow walking (2 mph) on the treadmill. Treadmill speed was then increased to a pre-determined level based on participant BMI to generate aerobic-level HRs for the duration of the 20-min bout of exercise. HR was recorded at 2-min intervals during exercise, and treadmill speed was adjusted to maintain exercise HRs between 65% and 75% of age-adjusted predicted maximal HR per recommended by the American College of Sports Medicine (ACSM, 2000) recommendations. Experimenter’s only contact with participants during the exercise protocol was to check HR and adjusting treadmill speed. Following exercise, participants completed a 2minute cool down period by walking at a pace of two mph on the treadmill. Resistance training. Participants in the resistance training condition received instruction in the proper form of three resistance exercises (i.e., squats, bench press, and lat pulldowns), and were required to exhibit correct form before beginning the exercises. Participants then completed 2 min of stretching, followed by a brief set of each exercise with no resistance added. Following the warmup exercises, participants completed two sets of each exercise to exhaustion (i.e., they could not do one more repetition) using a weight they were able to perform at least 10 repetitions with during their initial set. Two minutes of rest was provided between sets. Participant HR was monitored at the completion of each set (i.e., exercise HR) and following 2 min of rest between each set. The number of sets and repetitions, and the timing of rest breaks were selected to ensure the exercises were challenging, physiologically arousing, and of comparable duration to the aerobic exercise condition. Rest condition. Participants in the rest condition sat quietly in a chair for 20 min and


5

were not permitted to engage in any activity during rest. HR was monitored at 2-min intervals. Five minutes after completion of their respective exercise/rest condition, participants completed the baseline series of questionnaires a second time, and were given instructions regarding the CO2 inhalation task. A spirometer was used to assess lung capacity, and vital capacity breathing was demonstrated. Following vital capacity breathing practice, participants were fitted with a nose clip and asked to exhale fully before inhaling one full breath of a 35% CO2/65% O2 mixture from a 4.8 l Venticomp bag filled to capacity. Participants were instructed to hold the breath containing the mixture for 5 s as the experimenter counted out loud before exhaling. Twenty seconds following exhalation, participants completed the API, rested quietly until any lingering anxiety symptoms subsided, and then completed the ASI-3 a third time.

Results Data analytic plan Study hypotheses were tested using condition by time mixed-model analyses of variance (ANOVAs) for each of the dependent measures. The repeated-measures factor had three levels (baseline, post-exercise/rest, and post-CO2 inhalation task) for the ASI-3 and API, and two levels (baseline and postexercise/rest) for the DTS, DIS, and STAI-S. Significant interaction effects were analyzed by examining within-group simple effects and post hoc mean comparisons.

Preliminary analyses Independent samples t-tests and Chi-square analyses indicated that the three groups were comparable at baseline on all demographic and outcome variables (all ps . .30, see Table 1). As seen in Table 2, ASI-3, API, DTS, and STAI-S scores were all significantly correlated at baseline ( ps , .001), whereas DIS scores were not significantly related to any of the other anxiety-related measures.

Manipulation check: heart rate during exercise/rest

A 3 £ 2 (group £ time) mixed-model ANOVA was computed to test the impact of condition

6



Table 2. Bivariate correlations between anxiety vulnerability measures at baseline Measure

ASI-3

API

DTS

DIS

STAI

ASI-3 API DTS DIS STAI-S

– .57* 2 .43* .11 .44*

– 2 .39* .03 .55*

– 2 .01 2 .44*

– .02

–


Note. *p , .001.

on participant HR. Results showed a significant main effect for time, F (1, 71) ¼ 254.10, p , .001, h2p ¼ :78, with HRs increasing from baseline resting HR (M ¼ 79.41, SD ¼ 20.32) to mean exercise/rest HR (M ¼ 113.05, SD ¼ 35.89). The main effect for group, F (1, 71) ¼ 17.60, p , .001, h2p ¼ :33, and interaction effect, F (2, 71) ¼ 105.16, p , .001, h2p ¼ :75, were also significant. Post hoc analyses revealed that the aerobic exercise condition exhibited significantly higher HRs during the intervention than the resistance training and rest conditions (see Table 1). Participants in the resistance training condition also demonstrated significantly higher HRs during exercise than they did following 2 min of rest after each set and in comparison with participants in the rest condition (all ps , .001). In addition, heart rates were significantly higher following completion of squats (M ¼ 133.75, SD ¼ 31.88) compared with the chest press (M ¼ 108.36, SD ¼ 26.85) and lat pulldown exercises (M ¼ 106.50, SD ¼ 34.26). Thus, the two exercise interventions generated significant increases in physiological arousal compared with rest.

Anxiety sensitivity

A 3 £ 3 (group £ time) mixed-model ANOVA on ASI-3 scores revealed a significant main effect for time, F (2, 148) ¼ 56.84, p , .001, h2p ¼ :43, with ASI-3 scores decreasing from baseline (M ¼ 10.29, SD ¼ 7.44) to postexercise/rest (M ¼ 7.61, SD ¼ 7.16) and post-CO2 inhalation (M ¼ 6.69, SD ¼ 6.78). Post hoc analyses indicated that the decrease from baseline to post-exercise was significant, as was the decrease from baseline to post-CO2 inhalation. However, the change in ASI-3 scores from post-exercise to post-CO2 inhalation was not significant. The group by time interaction was significant, F (4, 148) ¼ 5.88,

p , .001, h2p ¼ :14. A significant simple effect for time emerged for the aerobic exercise group, F (2, 48) ¼ 26.35, p , .001, h2p ¼ :52, with post hoc tests revealing that aerobic group ASI-3 scores significantly declined from baseline to post-exercise and were maintained though CO2 inhalation (see Table 3 and Figure 2). However, post-CO2 inhalation, ASI-3 scores were not significantly different compared with post-aerobic exercise scores. An effect of time was also found for the resistance training comparison group, F (2, 50) ¼ 25.81, p , .001, h2p ¼ :52, with post hoc tests indicating that ASI-3 scores significantly declined from baseline to post-resistance training. In addition, ASI-3 scores continued to significantly decline from post-resistance training through post-CO 2 inhalation. A significant simple effect also emerged for the rest condition, F (2, 50) ¼ 5.65, p ¼ .009, h2p ¼ :18, with post hoc tests indicating that the rest group exhibited a significant decrease in ASI-3 scores from baseline to post-CO2

Table 3. Group means and standard deviations at each assessment period for outcome measures Aerobic exercise (n ¼ 25) Measure ASI-3 Baseline Post-Ex/rest Post-CO2 API Baseline Post-Ex/rest Post-CO2 DTS Baseline Post-Ex/rest DIS Baseline Post-Ex/rest STAI-S Baseline Post-Ex/rest

M

SD

10.92 6.47 6.96 5.54 6.16 5.34

Resistance training (n ¼ 26) M

SD

Rest (n ¼ 26) M

SD

9.77 7.29 10.23 8.62 6.35 5.18 9.50 9.68 5.11 4.76 8.77 9.06

3.16 3.39 3.76 3.14 3.56 3.96

3.27 3.35 3.08 2.80 4.85 3.50

3.19 4.60 2.89 5.14 6.46 5.91

3.73 3.82

3.93 3.89

3.79 3.88

.70 .80

.74 .72

11.36 4.42 9.85 4.97 10.80 4.67 10.27 5.33

.84 .78

9.42 4.72 9.19 4.29

30.28 6.73 30.65 6.31 28.54 7.43 31.32 8.38 32.54 7.82 28.35 7.90

Notes. ASI-3, Anxiety Sensitivity Index – 3; API, Acute Panic Inventory; DTS, Distress Tolerance Scale; DIS, Discomfort Intolerance Scale; STAI-S, State-Trait Anxiety Inventory – State Scale. No baseline group differences emerged for any of the above measures.

2015


7

API Scores

12 10 8 6 4

Aerobic Exercise Resistance Training Rest


2 0 Baseline 7

Post-Exercise-Rest

Post-CO2

API Scores

6 5 4 3 2 Aerobic Exercise Resistance Training Rest

1 0 Baseline

Post-Exercise/Rest

Post-CO2

Figure 2. Mean ASI-3 (top) and API (bottom) scores at baseline, post-exercise/rest, and post-CO2 inhalation.

inhalation ( p ¼ .009), though the changes in scores from baseline to post-rest and post-rest to post-CO2 inhalation were not statistically significant. Although Jacobson and Truax (1991) recommend using outcome score changes of 1.96 SD or more as a criterion for clinically meaningful change, given that the present sample was not selected for high AS, meaningful change was defined as a 1 SD (i.e., seven point) or greater reduction in ASI-3 scores. Chi-square analyses of clinically meaningful change in ASI-3 scores at post-exercise revealed that the resistance training group had significantly more treatment responders (n ¼ 5; 19%) than the control

condition (n ¼ 0), x 2 (1, N ¼ 52) ¼ 5.53, p ¼ .02, and the aerobic group had marginally more treatment responders (n ¼ 3; 12%) than control, x 2 (1, N ¼ 51) ¼ 3.32, p ¼ .07. There was not a significant difference in number of treatment responders between the exercise conditions ( p ¼ .48). At post-CO2 inhalation, the resistance training group had significantly treatment responders (n ¼ 7; 26%) than the x2 (1, control condition (n ¼ 0), N ¼ 52) ¼ 8.09, p ¼ .004, as did aerobic exercise group (n ¼ 6; 24%) compared with the control condition, x 2 (1, N ¼ 51) ¼ 7.07, p ¼ .008. The number of treatment responders in the exercise conditions did not significantly differ ( p ¼ .81).

8



CO2 reactivity

A 3 £ 3 mixed-model ANOVA of API scores revealed a significant effect of time, F (2, 148) ¼ 15.54, p , .001, h2p ¼ :17, with API scores remaining consistent from baseline (M ¼ 3.21, SD ¼ 3.78) to post-exercise/rest (M ¼ 3.23, SD ¼ 3.81), but significantly increasing post-CO2 inhalation (M ¼ 4.97, SD ¼ 4.67). The group by time interaction was significant, F (4, 148) ¼ 5.06, p ¼ .001, h2p ¼ :12, and simple effects analyses revealed that the aerobic exercise group did not exhibit a significant change in API scores over time ( p ¼ .48). In contrast, the resistance training condition exhibited a significant increase in API scores over time, F (2, 50) ¼ 4.33, p ¼ .02, h2p ¼ :15, with the effect occurring between post-exercise and post-CO2 inhalation. The rest condition also exhibited a statistically significant increase in API scores over time, F (2, 50) ¼ 16.93, p , .001, h2p ¼ :40, with the effect occurring between post-rest and postCO2 inhalation. One-way ANOVAs comparing conditions on API change scores from baseline to post-CO2 inhalation and postexercise to post-CO2 inhalation revealed significant group differences ( ps ¼ .03 and .001 respectively). Post hoc t-tests revealed that the rest condition exhibited significantly greater increases in API scores compared with the aerobic condition from baseline to post-CO2 inhalation ( p ¼ .009) and postexercise to post-CO2 ( p , .001). In contrast, the rest condition exhibited non-significant trends toward larger increases API scores compared with the resistance training condition (baseline to post-CO2 p ¼ .10, and p ¼ .15). post-training to post-CO 2 A comparison of the two exercise conditions revealed that the groups did not differ in change scores from baseline to post-CO2, though the resistance training condition demonstrated a significantly larger increase in API scores from post-exercise to post-CO2 inhalation ( p ¼ .03).

DT, DI, and state anxiety

Separate 3 £ 2 mixed-model ANOVAs were conducted to analyze changes in DT, DIS, and STAI-S scores from baseline to postexercise. No significant main or interaction effects emerged from these analyses (all ps . .10).


Discussion Consistent with prediction, results of this study provide further support for the ameliorative effects of aerobic exercise on AS and CO2 reactivity. Specifically, individuals who engaged in a single bout of aerobic exercise reported significantly greater reductions in ASI-3 scores from baseline to post-exercise compared with a rest control condition, with more than 20% of aerobic exercisers exhibiting a clinically meaningful decrease in AS. These findings corroborate previous research indicating that anxiety-related bodily sensations significantly decreased following the first session of aerobic exercise (Broman-Fulks et al., 2004). Results of this study also indicated that aerobic exercise led to significantly less reactivity to a CO2 challenge task, with individuals who completed a session of aerobic exercise exhibiting non-significant changes in API scores from baseline to postCO2 inhalation. In contrast, control participants reported significantly higher API scores post-CO2 inhalation relative to those observed in the aerobic condition. Thus, aerobic exercise appeared to attenuate participant reactivity to anxiety-related sensations generated by the CO2 inhalation task, which is consistent with the results of prior research using single and multiple exercise sessions among healthy samples and panic disorder patients (e.g., Smits, Meuret, Zvolensky, Rosenfield, & Seidel, 2009; Stro¨hle et al., 2009). Similar to aerobic exercise, a single session of resistance training led to a significant decrease in AS scores, with the decline in scores being significantly larger than that observed in the control condition and more than 25% of exercisers exhibiting clinically meaningful change. The magnitude of the reductions in AS scores generated by resistance training was identical to that produced by aerobic exercise (h2p ¼ :52), and the two forms of exercise generated comparable numbers of participants that exhibited clinically meaningful levels of change in AS. Thus, repeated exposure to physiological arousal generated by short, intense bursts of physical activity over a 20-min period appears to be equally effective in reducing AS compared with a 20-min period of prolonged somatic arousal. In contrast, resistance training was significantly less effective than aerobic exercise


2015

at mitigating participant reactivity to CO2 inhalation. Specifically, although level of panic symptomology remained consistent over time among individuals engaging in aerobic exercise, participants in the resistance training condition demonstrated a significant increase in panic symptoms in response to the CO2 challenge task. However, it is important to note that, although not statistically significant, resistance training participants did demonstrate a trend toward lower panic symptomology in response to biological challenge relative to those in the control condition. Thus, a single bout of resistance training or aerobic exercise both represent effective means of reducing fears of anxietyrelated sensations, though aerobic exercise appears to have some advantages in that it leaves participants less vulnerable to responding fearfully to arousal-inducing stimuli. Although aerobic exercise and resistance training exhibited relatively large effects on AS, neither form of exercise exerted observable effects on DT or DI. Conceptual differences between AS, DI, and DT may help to explain this pattern of results. Although AS is theorized to reflect fears of somatic sensations experienced during anxious arousal, DT and DI reflect reactions to a broader array of negative affective states and physiological sensations (Mitchell, Riccardi, Keough, Timpano, & Schmidt, 2013). Modern inhibitory learning models posit that exposure therapy is maximized when the fear network is activated so that expectancies for the fear-eliciting stimuli can be violated and new, secondary learning can occur (Craske et al., 2008). Based on this model, aerobic exercise and resistance training may be effective in reducing AS and CO2 reactivity because exercise elicits the specific sensations feared by individuals with high AS or experienced during a CO 2 inhalation task in a presumably healthy, non-threatening context, and thus facilitates learning of competing, non-threat associations for arousal sensations. In contrast, exercise interventions may not elicit the broader range of negative emotions and sensations associated with DT and DI, and thereby diminish the likelihood of exercise producing inhibitory learning to distressing emotions or physical discomfort. The results of this study indicated that neither form of exercise generated significant


9

reductions in state anxiety at 5 min postexercise. This finding appears to conflict with the results of a several previous studies, which have indicated that a single bout of aerobic exercise is associated with significant reductions in state anxiety (e.g., Raglin & Wilson, 1996). However, some research suggests that the anxiolytic effect of aerobic exercise is slightly delayed. For example, Cox, Thomas, and Davis (2000) found reductions in state anxiety were observable at 30-min postaerobic exercise but not at 5 min post-exercise. In contrast, the lack of change in state anxiety among the resistance training condition is largely consistent with previous research, which has indicated that a single bout of resistance training has either negligible impact on state anxiety (e.g., Raglin et al., 1993) or the impact is delayed 30 min or more (e.g., Bartholomew & Linder, 1998; Bibeau, Moore, Mitchell, Cargas-Tonsing, & Bartholomew, 2010). Thus, the absence of an observable effect of aerobic exercise or resistance training on state anxiety may be attributable to the relatively short interval between exercise termination and anxiety assessment. Positive effects of acute aerobic exercise and resistance training on AS and attenuation of reactivity to stimuli that may induce panic has important implications for anxiety treatment. Given that high AS and CO2 reactivity represent vulnerabilities for the development and maintenance of panic attacks, anxiety disorders, mood disorders, and substance use disorders (e.g., Schmidt et al., 2006), and exercise reduces AS and CO2 reactivity, it is possible that a single session of exercise may decrease risk for various forms of psychopathology. Further, previous research has indicated that six sessions of aerobic exercise over a 2-week period may generate slightly larger effect sizes than those noted here (e.g., Broman-Fulks et al., 2004h2p ¼ :60 vs. present study h2p ¼ :52) and a larger percentage of treatment responders (62% vs. 24– 26% in this study). Thus, repeated engagement in aerobic exercise may serve to further reduce psychopathology risk. The present findings may be useful to include in psychoeducation when clinicians are working toward implementation of stand-alone or adjunctive exercise interventions with clients. Research suggests that changing client lifestyles to include regular exercise is a challenging endeavor, and


10


adherence to regular exercise regimens is generally low (Dishman, 1991). However, knowledge that the benefits of exercise for individuals with AS-related psychopathology begin immediately following the initial session and appear to continue for as long as the individual maintains regular exercise engagement may help to increase client willingness to begin and adhere to a new exercise regimen. Finally, given the cumulative research supporting the efficacy of physical exercise interventions for anxiety and certain anxiety risk factors, clinicians should consider integrating exercise into standard CBT protocols or recommending exercise as a stand-alone intervention for anxious individuals who encounter barriers (e.g., lack of access, financial constraints and stigma concerns) to efficacious psychotherapy programs. Although this study has several notable strengths, including a randomized controlled design and measures of multiple cognitive vulnerability factors, several potential limitations and directions for future research are worthy of discussion. First, the sample comprised a non-selected group of young adults, and thus the extent to which the present findings extend to at-risk or clinical samples is unclear. Although the range of scores on each of the anxiety vulnerability measures extended into clinical realm (e.g., Taylor et al., 2007) and approximately 12% of the sample met criteria for an anxiety disorder according to a structured interview, it will be important for future research to replicate these findings among anxiety vulnerable and clinical samples. Second, the intensity of the aerobic exercise and resistance training interventions were relatively homogenous and in the moderate range. Although research suggests that mild to moderate intensity exercise may be most beneficial for reducing anxiety (e.g., Bibeau et al., 2010; O’Connor, Bryant, Veltri, & Gebhardt, 1993; Tsutsumi et al., 1998), future studies would benefit from investigating the full range of exercise intensity on anxiety vulnerability factors to optimize treatment recommendations for at-risk or clinical populations. Additional research is also warranted to determine whether resistance training exercises that engage larger muscle groups and generate larger increases in physiological arousal (e.g., squats/leg presses) may be more beneficial for affecting AS and other vulnerability factors.


Given increasing evidence supporting exercise interventions for anxiety and mood disorders, comparisons of the efficacy of aerobic exercise and resistance training with other well-established treatments for anxiety vulnerable populations (e.g. CBT) in varying dosages would help to determine when peak benefits are obtained. In addition, longitudinal exercise intervention studies of greater duration (i.e., . 2 weeks) are necessary to evaluate changes in anxiety vulnerability measures over longer periods of time, and long-term followup studies would help to determine the durability of effects once exercise interventions are discontinued. Finally, although exercise has been shown to reliably reduce AS and CO2 reactivity, additional research is needed to determine the extent to which exercise-induced reductions in anxiety vulnerability factors translate into actual decreased risk of developing anxiety pathology.

Disclosure statement The authors have declared that no conflict of interest exists.

References American College of Sports Medicine (2000). ACSM’s guidelines for exercise testing and prescription (6th ed.). Baltimore, MD: Lippincott Williams and Wilkins. Asmundson, G.J.G., Fetzner, M.G., DeBoer, L.B., Powers, M.B., Otto, M.W., & Smits, J.A.J. (2013). Let’s get physical: A contemporary review of the anxiolytic effects of exercise for anxiety and its disorders. Depression and Anxiety, 30, 362– 373. doi:10.1002/da.22043 Bartholomew, J.B., & Linder, D.E. (1998). State anxiety following resistance exercise: The role of gender and intensity. Journal of Behavioral Medicine, 21, 205– 219. doi:10.1023/A:1018732 025340 Bibeau, W.S., Moore, J.B., Mitchell, N.G., VargasTonsing, T., & Bartholomew, J.B. (2010). Effects of acute resistance training of different intensities and rest periods on anxiety and affect. Journal of Strength and Conditioning Research, 24, 2184 – 2191. doi:10.1519/JSC. 0b013e3181ae794b Broman-Fulks, J.J., Berman, M.E., Rabian, B., & Webster, M.J. (2004). Effects of aerobic exercise on anxiety sensitivity. Behaviour Research and Therapy, 42, 125– 136. doi:10.1016/S0005-7967 (03)00103-7 Broman-Fulks, J.J., & Storey, K.M. (2008). Evaluation of a brief aerobic exercise interven-


2015

tion for high anxiety sensitivity. Anxiety, Stress, & Coping, 17, 17– 28. Broocks, A., Bandelow, B., Pekrun, G., George, A., Meyer, T., Bartmann, U., . . . , & Ruether, E. (1998). Comparison of aerobic exercise, clomipramine, and placebo in the treatment of panic disorder. American Journal of Psychiatry, 155, 603– 609. doi:10.1176/ajp.155.5.603 Brown, R.A., Abrantes, A.M., Strong, D.R., Mancebo, M.C., Menard, J., Rasmussen, S.A., & Greenberg, B.D. (2007). A pilot study of moderate-intensity aerobic exercise for obsessive compulsive disorder. The Journal of Nervous and Mental Disease, 195, 514– 520. doi:10.1097/01.nmd.0000253730.31610.6c Cardinal, B.J., Esters, J., & Cardinal, M.K. (1996). Evaluation of the revised physical activity readiness questionnaire in older adults. Medicine & Science in Sports & Exercise, 28, 468 – 472. doi:10.1097/00005768-19960400000011 Cox, R.H., Thomas, T.R., & Davis, J.E. (2000). Delayed anxiolytic effect associated with an acute bout of aerobic exercise. Journal of Exercise Physiology, 3, 59 – 66. Craske, M.G., Kircanski, K., Zelikowsky, M., Mystkowski, J., Chowdhury, N, & Baker, A. (2008). Optimizing inhibitory learning during exposure therapy. Behaviour Research and Therapy, 46, 5 – 27. doi:10.1016/j.brat.2007.10. 003 Dishman, R.K. (1991). Increasing and maintaining exercise and physical activity. Behavior Therapy, 22, 345– 378. doi:10.1016/S0005-7894 (05)80371-5 Foa, E., & Kozak, M.J. (1986). Emotional processing of fear: Exposure to corrective information. Psychological Bulletin, 99, 20– 35. doi:10.1037/0033-2909.99.1.20 Fremont, J., & Craighead, L.W. (1987). Aerobic exercise and cognitive therapy in the treatment of dysphoric moods. Cognitive Therapy and Research, 11, 241 – 251. doi:10.1007/ BF01183268 Gallagher, M.W., Payne, L.A., White, K.S., Shear, K.M., Woods, S.W., Gorman, J.M., & Barlow, D.H. (2013). Mechanisms of change in cognitive behavioral therapy for panic disorder: The unique effects of self-efficacy and anxiety sensitivity. Behaviour Research and Therapy, 51, 767– 777. doi:10.1016/j.brat.2013.09.001 Gaudlitz, K., Plaq, J., Dimeo, F., & Strohle, A. (2015). Aerobic exercise training facilitates the effectiveness of cognitive behavioral therapy in panic disorder. Depression & Anxiety, 32, 221– 228. Hale, B.S., & Raglin, J.S. (2002). State anxiety responses to acute resistance training and step aerobic exercise across eight weeks of training. Journal of Sports Medicine and Physical Fitness, 42, 108– 112. Herring, M.P., Jacob, M.L., Suveg, C., Dishman, R., & O’Connor, P.J. (2012). Feasibility of exercise training for the short-term treatment of generalized anxiety disorder: A randomized


11

controlled trial. Psychotherapy and Psychosomatics, 81, 21 – 28. doi:10.1159/000327898 Hoffman, S.G., & Smits, J.A.J. (2008). Cognitivebehavioral therapy for adult anxiety disorders: A meta-analysis of randomized placebo-controlled trials. The Journal of Clinical Psychiatry, 69, 621–632. doi:10.4088/JCP.v69n0415 Jacobson, N.S., & Truax, P. (1991). Clinical significance: A statistical approach to defining meaningful change in psychotherapy research. Journal of Consulting and Clinical Psychology, 59, 12 –19. Keough, M.E., Riccardi, C.J., Timpano, K.R., Mitchell, M.A., & Schmidt, N.B. (2010). Anxiety symptomatology: The association with distress tolerance and anxiety sensitivity. Behavior Therapy, 41, 567– 574. doi:10.1016/j. beth.2010.04.002 Kessler, K.S., Berglund, P., Demler, O., Jin, R., Merikangas, K.R., & Walters, E.E. (2005). Lifetime prevalence and age-of-onset distributions of DSM-IV disorders in the National Comorbidity Survey Replication. Archives of General Psychiatry, 62, 593– 602. doi:10.1001/ archpsyc.62.6.593 Liebowitz, M.R., Gorman, J.M., Fyer, A.J., Dillon, D.J., & Klein, D.F. (1984). Effects of naloxone on patients with panic attacks. American Journal of Psychiatry, 141, 995– 997. doi:10. 1176/ajp.141.8.995 Manger, T.A., & Motta, R.W. (2005). The impact of an exercise program on posttraumatic stress disorder, anxiety, and depression. International Journal of Emergency Mental Health, 7, 49 – 57. Marshall, W.L. (1985). The effects of variable exposure in flooding therapy. Behavior Therapy, 16, 117 – 135. doi:10.1016/S0005-7894(85) 80040-X Merom, D., Phongsavan, P., Wagner, R., Chey, T., Marnane, C., Steel, Z., . . . & Bauman, A. (2008). Promoting walking as an adjunct intervention to group cognitive behavioral therapy for anxiety disorders – A pilot group randomized trial. Journal of Anxiety Disorders, 22, 959– 968. doi:10.1016/j.janxdis. 2007.09.010 Mitchell, M.A., Riccardi, C.J., Keough, M.E., Timpano, K.R., & Schmidt, N.B. (2013). Understanding the associations among anxiety sensitivity, distress tolerance, and discomfort intolerance: A comparison of three models. Journal of Anxiety Disorders, 27, 147–154. doi:10.1016/j.janxdis.2012.12.003 Mohr, D.C., Ho, J., Duffecy, J., Baron, K.G., Lehman, K.A., Jin, L., & Reifler, D. (2010). Perceived barriers to psychological treatments and their relationship to depression. Journal of Clinical Psychology, 66, 394– 409. National Institute of Mental Health (2001). Mental disorders in America [online]. www.nimh.nih. gov O’Connor, P.J., Bryant, C.X., Veltri, J.P., & Gebhardt, S.M. (1993). State anxiety and ambulatory blood pressure following resistance exercise in females. Medicine & Science in Sports


12


& Exercise, 25, 516– 521. doi:10.1249/00005768199311000-00016 O’Connor, P.J., Herring, M.P., & Caravalho, A. (2010). Mental health benefits of strength training in adults. American Journal of Lifestyle Medicine, 4, 377 – 396. doi:10.1177/ 1559827610368771 Raglin, J.S., Turner, P.E., & Eksten, F. (1993). State anxiety and blood pressure following 30 min of leg ergometry or weight training. Medicine & Science in Sports & Exercise, 25, 1044 – 1048. doi:10.1249/00005768-19930900000012 Raglin, J.S., & Wilson, M. (1996). State anxiety following 20 minutes of bicycle ergometer exercise at selected intensities. International Journal of Sports Medicine, 17, 467 – 471. doi:10.1055/s-2007-972880 Reiss, S. (1991). Expectancy model of fear. Clinical Psychology Review, 11, 141– 153. Schmidt, N.B., Lerew, D.R., & Jackson, R.J. (1997). The role of anxiety sensitivity in the pathogenesis of panic: Prospective evaluation of spontaneous panic attacks during acute stress. Journal of Abnormal Psychology, 106, 355– 364. doi:10.1037/0021-843X.106.3.355 Schmidt, N.B., Maner, J.K., & Zvolensky, M.J. (2007). Reactivity to challenge with carbon dioxide as a prospective predictor of panic attacks. Psychiatry Research, 151, 173– 176. doi:10.1016/j.psychres.2006.11.006 Schmidt, N.B., Richey, J.A., Cromer, K.R., & Buckner, J.D. (2007). Discomfort intolerance: Evaluation of a potential risk factor for anxiety psychopathology. Behavior Therapy, 38, 247–255. doi:10.1016/j.beth.2006.08.004 Schmidt, N.B., Richey, J.A., & Fitzpatrick, K.K. (2006). Discomfort intolerance: Development of a construct and measure relevant to panic disorder. Journal of Anxiety Disorders, 20, 263–280. doi:10.1016/j.janxdis.2005.02.002 Schmidt, N.B., Trakowski, J.H., & Staab, J.P. (1997). Extinction of panicogenic effects of a 35% CO2 challenge in patients with panic disorder. Journal of Abnormal Psychology, 106, 630–638. doi:10.1037/0021-843X.106.4.630 Schmidt, N.B., & Zvolensky, M.J. (2007). Anxiety sensitivity and CO2 challenge reactivity as unique and interactive prospective predictors of anxiety pathology. Depression and Anxiety, 24, 527– 536. doi:10.1002/da.20267 Schmidt, N.B., Zvolensky, M.J., & Maner, J.K. (2006). Anxiety sensitivity: Prospective predic-


tion of panic attacks and axis 1 pathology. Journal of Psychiatric Research, 40, 691– 699. doi:10.1016/j.jpsychires.2006.07.009 Seim, R.W., Waller, S.A., & Spates, C.R. (2010). A preliminary investigation of continuous and intermittent exposures in the treatment of public speaking anxiety. International Journal of Behavioral Consultation and Therapy, 6, 84 – 94. doi:10.1037/h0100903 Simons, J.S., & Gaher, R.M. (2005). The Distress Tolerance Scale: Development and validation of a self-report measure. Motivation and Emotion, 29, 83 – 102. doi:10.1007/s11031-005-7955-3 Smits, J.A.J., Berry, A.C., Rosenfield, D., Powers, M.B., Behar, E., & Otto, M.W. (2008). Reducing anxiety sensitivity with exercise. Depression and Anxiety, 25, 689– 699. doi:10. 1002/da.20411 Smits, J.A.J., Meuret, A.E., Zvolensky, M.J., Rosenfield, D., & Seidel, A. (2009). The effects of acute exercise on co2 challenge reactivity. Journal of Psychiatric Research, 43, 446– 454. doi: 10.1016/j.jpsychires.2008.05.009 Spielberger, C.D., Gorsuch, R.L., Lushene, R.E., & Jacobs, G.A. (1983). State-trait anxiety inventory for adults. Palo Alto, CA: Consulting Psychologists Press. Stro¨hle, A., Graetz, B., Scheel, M., Wittmann, A., Feller, C., Heinz, A., & Dimeo, F. (2009). The acute antipanic and anxiolytic activity of aerobic exercise in patients with panic disorder and healthy control subjects. Journal of Psychiatric Research, 43, 1013–1017. doi:10. 1016/j.jpsychires.2009.02.004 Taylor, S., Zvolensky, M.J., Cox, B.J., Deacon, B., Heimberg, R.G., Ledley, D.R., . . . & Cardenas, S.J. (2007). Robust dimensions of anxiety sensitivity: Development and initial validation of the Anxiety Sensitivity Index-3. Psychological Assessment, 19, 176– 188. doi:10.1037/10403590.19.2.176 Tsutsumi, T., Don, B.M., Zaichkowsky, L.D., Takenaka, K., Oka, K., & Ohno, T. (1998). Comparison of high and moderate intensity of strength training on mood and anxiety in older adults. Perceptual and Motor Skills, 87, 1003– 1011. doi:10.2466/pms.1998.87.3.1003 Wang, P.S., Lane, M., Olfson, M., Pincus, H.A., Wells, K.B., & Kessler, R.C. (2005). Twelvemonth use of mental health services in the United States. Archives of General Psychiatry, 62, 629– 640. doi:10.1001/archpsyc.62.6.629

The Acute Effects of a Single Bout of Moderate-intensity Aerobic Exercise on Cognitive Functions in Healthy Adult Males.

The influence of a single bout of aerobic exercise on short-interval intracortical excitability.

Effects of a single bout of lower-body aerobic exercise on muscle activation and performance during subsequent lower- and upper-body resistance exercise workouts.

The immediate effects of a single bout of aerobic exercise on oral glucose tolerance across the glucose tolerance continuum.

Effect of combined aerobic and resistance training versus aerobic training on arterial stiffness.

About the article: Effect of combined aerobic and resistance training versus aerobic training on arterial stiffness.

Effects of aerobic training, resistance training, or combined resistance-aerobic training on the left ventricular myocardium in a rat model.

Influence of single bout of aerobic exercise on aortic pulse pressure.

Effects of an acute bout of aerobic exercise on cardiovascular and subjective responses during subsequent cognitive work.

Effect of a single bout of resistance exercise on arterial stiffness following a high-fat meal.

Effects of cognitive training with and without aerobic exercise on cognitively demanding everyday activities.

A Single Bout of Moderate Aerobic Exercise Improves Motor Skill Acquisition.

Effects of a Single Bout of Resistance Exercise in Different Volumes on Endothelium Adaptations in Healthy Animals.

Resistance training as a preconditioning strategy for enhancing aerobic exercise training outcomes in COPD.

Effects of combined training vs aerobic training on cognitive functions in COPD: a randomized controlled trial.

Impact of a single bout of aerobic exercise on regional brain perfusion and activation responses in healthy young adults.

Cycle training modulates satellite cell and transcriptional responses to a bout of resistance exercise.

How much will older adults exercise? A feasibility study of aerobic training combined with resistance training.

Delineating the effects of aerobic training versus aerobic capacity on satellite cell behaviour in humans.

Online cognitive training in healthy older adults: a preliminary study on the effects of single versus multi-domain training.

A Single Bout of Aerobic Exercise Reduces Anxiety Sensitivity But Not Intolerance of Uncertainty or Distress Tolerance: A Randomized Controlled Trial.

Cognitive Vulnerabilities for Depression and Anxiety in Childhood: Specificity of Anxiety Sensitivity and Rumination.

A single bout of resistance exercise can enhance episodic memory performance.

Caffeine attenuates acute growth hormone response to a single bout of resistance exercise.