858 Behavioural Sciences
Acute Exercise Increases Sex Differences in Amateur Athletes’ Risk Taking
Authors
S. Pighin1, 2, L. Savadori3, N. Bonini3, L. Andreozzi3, A. Savoldelli1, F. Schena1, 4
Affiliations
1
Key words ▶ physical exercise ● ▶ athletes ● ▶ decision making ● ▶ risk taking ● ▶ sex differences ●
Abstract
University of Verona, Research Center “Sport, Mountain and Health”, Trento, Italy Center for Experimental Research in Management and Economics, DCP, University IUAV of Venice, Venice, Italy 3 Department of Economics and Management, University of Trento, Trento, Italy 4 Neurological and Motor Science, University of Verona, Verona, Italy
▼
The research presented here investigates the interaction between acute exercise, biological sex and risk-taking behavior. The study involved 20 amateur athletes (19–33 years old), 10 males and 10 females, who were asked to undergo subsequent experimental sessions designed to com-
Introduction
▼
accepted after revision January 13, 2015 Bibliography DOI http://dx.doi.org/ 10.1055/s-0034-1398677 Published online: June 19, 2015 Int J Sports Med 2015; 36: 858–863 © Georg Thieme Verlag KG Stuttgart · New York ISSN 0172-4622 Correspondence Stefania Pighin, Phd Research Center “Sport, Mountain and Health” University of Verona Via Matteo del Ben 5/B, 38068 Trento Italy [email protected]
A substantial body of literature has investigated how physiological responses to acute exercise affect human behavior and cognition for a recent meta-analysis see [14]. Whereas the general issue of whether acute exercise has a beneficial or a detrimental effect on cognitive performances is still debated, there is substantial agreement that the effect of acute exercise on cognitive performance is strictly dependent on the nature of the cognitive task involved. Acute exercise seems to have a considerable positive effect on motor skills, reaction times and academic achievements [58] but negative effects on reasoning and verbal skills [24], on memory [25, 63] and on executive functions or frontal-lobe dependent measures [12, 13, 19, 20, 49, 59]. The cognitive task type is one of the primary moderators of the effect of acute exercise on cognition, along with the exercise intensity, the time of the cognitive test administration and the individual fitness level [14]. Interestingly, very few studies have investigated the effect of acute exercise on complex cognitive functions [14] and, to the best of our knowledge, no research has previously examined risk-taking behavior during an exercise session. Physical exercise is assumed to influence the cerebral systems associated with pleasure and mood regulation, increasing dopamine activation in critical sub-cortical brain regions [21, 47]. Among other
Pighin S et al. Acute Exercise & Risk Taking … Int J Sports Med 2015; 36: 858–863
pare their risky behaviors on the Balloon Analogue Risk Task (BART) [34] at rest and while exercising at moderate intensity (60 % of their maximal aerobic power). Results showed that physical exercise affected male and female participants differently: Whereas males became more risk seeking, females became more risk averse during exercise.
things, dopamine is recognized as a factor affecting risk-taking behaviors due to the activation of brain regions that are associated with novelty seeking and reward processing [22, 46, 61]. Neurobiological evidence suggests that acute exercise may affect risk propensity due to the resulting increase in dopamine production [19], which has been associated with an increase in risk taking [22, 61]. Therefore, we would expect to observe increased risk-taking behavior during exercise. Additional insights regarding the effect of exercise on risk taking can be found in the literature on acute stress. Indeed, the link between a single session of acute exercise and acute stress is well recognized [6]: the physiological changes induced by exercise (e. g., increased heart rate, increased respiratory rate, increased blood pressure, sweating, etc.) are observed under physically stressful conditions (as well as in states of high arousal). During moments of exercise and/ or acute stress, levels of adrenaline and noradrenaline increase in blood plasma and produce similar effects in the central nervous system [15]. The few existing studies relating acute stress to decision making indicate that acute stress can temporarily alter individual decisional behavior, particularly when decisions involve weighing risks vs. rewards [39, 42–45, 52]. Acute stress elicits automatic responses incorporating little cognitive reflection and is associated with a predominantly negative effect on decisional pro-
Downloaded by: National University of Singapore. Copyrighted material.
2
cesses for a review see [53]. Risk taking is a special case within decision-making behavior. Different definitions of risk taking exist and lead to differing approaches to the study of risk taking [48]. One preferred laboratory approach uses incentivized tasks to elicit individual risk preferences and to assess risk attitudes relevant in real-world settings by ascertaining behavioral responses to a real opportunity to win a certain amount of money see [9]. The Balloon Analogue Risk Task (BART) [34], for example, is a standard incentivized task that models real-world risk behavior in the context of balancing potential reward and harm [31, 34] in a dynamic learning environment (individuals receive an immediate feedback as in many real-world choices). Several psychometric works have suggested that the BART has reasonable measurement properties, including construct validity and test-retest reliability [32, 62], and that it is a valid and strong predictor of risk-taking behavior in different real-world risky domains. In this task, participants pump, repeatedly, a virtual balloon without knowing when it will explode. Each pump increases the potential reward but also the probability of explosion, which, if it occurs, wipes out all potential gains for that trial. Balloon explosion probabilities are drawn from a uniform distribution, and participants must learn explosion probabilities through trial-and-error. Previous research has supported the validity of this task and demonstrated a strong relationship with a wide range of maladaptive risky behaviors occurring outside the laboratory. An increased risk taking on the BART, for example, was found to be significantly related to drug and alcohol use, gambling, smoking, aggression, stealing and unprotected sexual behaviors [1, 33, 35]. In general, evidence indicates that males are more likely to engage in risky behavior see [8], such as alcohol and drug abuse [28, 51], risky investment decisions [16, 29, 54] and fatal car accidents [40]. Laboratory tasks using monetary gambles have also indicated that males are greater risk takers than females for a review see [34], and risk-taking behavior on the BART proves no exception see, e. g., [34]. In an attempt to explain sex differences in risk-taking behavior, an evolutionary account has been proposed. The parental investment theory [60] implies that men compete with one another over mating opportunities, suggesting that sex differences in risk-taking may be the product of male’s high degree of competition during mating [23]. Risk-taking among men can signal particular traits to women and to other men [2]. Risky behaviors among men, for example, have the potential of displaying to potential mates characteristics such as social dominance, confidence, ambition, skill and mental acuity, all of which are highly desired by women seeking a romantic partner [5, 36, 50]. Males therefore would demonstrate a pattern of greater risk-taking behavior compared to females, especially after anger induction [17, 18] because this trait has been historically preferred during mating competition. In summary, both stress and the sex of the participant appear to impact risk-taking behavior independently. However, there is evidence that sex differences and stress might affect risk taking jointly, as well. When the effect of stress on risk taking has been measured, differences between the sexes have been observed. Stress has been shown to increase risk taking in males and decrease risk taking in females [37]. This result was recently supported by brain imaging evidence: Stress has been shown to have opposite effects on brain activation and behavior for males and females [38]. Specifically, under stress, evidence has shown that males have an increased activation of the dorsal striatum and of the anterior insula, whereas females have a decreased
activation of the same areas. These areas are assumed to be related to decisional and reward processing, and their differential activation seemed to lead to different behaviors: Under stress, males were more sensitive to rewards while females were less sensitive [38]. Lighthall and colleagues [37] referred to evolutionary principles to explain this result. While the fight-orflight response [11] is considered the primary physiological response to stress for both males and females due to its self-survival relevance, some authors suggested the females’ stress responses could be marked by a pattern termed “tend-tobefriend”, focused on maximizing the survival of self and offspring. Such response would involve protection behaviors, the reduction of neuroendocrine responses that may compromise one’s own and the offspring’s health, and affiliating behaviors in order to reduce risks [55]. In line with Taylor and colleagues’ theory [55], the pressure imposed by natural selection seems to be reflected in different behavioral responses to stress in males and females. Males’ tendency to be more risk seeking under stress in laboratory conditions would be analogous to the “fight” response showed by our ancestors in competitive situations. In contrast, females’ tendency to be more risk averse under stress in laboratory conditions would be analogous to the beneficial, conservative and protective “tend-to-befriend” response showed by our female ancestors. Sex differences in stress responses may be rooted in differential neuroendocrine mechanisms: acute stress increases testosterone in males, which is a good predictor of aggressive responses in stressful situations [26], while it increases oxytocin in females, which seems to have a calming effect [10, 41]. Despite the fact that such differences in neuroendocrine responses could reflect differential selection pressure and reproductive behaviors, the interaction between stress, biological sex and risk taking is still under investigation. The premise underlying the present study was that physiological changes in response to physical exercise may influence risktaking behaviors, having different effects in males and females. The goal of the present research was thus to examine the effect of acute physical exercise on risk-taking behavior in males and females. Our prediction is that acute exercise increases sex differences in risk taking: we expect acute exercise to increase risk taking in males and decrease risk taking in females. To test for this prediction the BART [34] was chosen as the dependent measure for (at least) 2 reasons. First, performances on the BART represent a reliable indication of individuals’ attitude toward risky behaviors, as they correlate with several behaviors related to addiction, safety and health [1, 32, 35]. Second, previous studies have shown greater risk-taking behavior in males and smaller risk-taking behavior in females under stress on the BART [37].
Materials & Method
▼
A sample of 20 amateur athletes volunteered to participate in the study: 10 males (mean age = 25.7 ± 3.9) and 10 females (mean age = 21.2 ± 1.83), who regularly practice sport at the amateur level, with a comparable degree of sports experience. Participants were recruited by contacting local sport associations and teams. They were invited to take part in a research project on the effect of exercise on decision making. All volunteers were required to fill out a questionnaire concerning their activity (e. g., number of weekly training sessions, duration of training, number of seasonal competitions, etc.). Participants with a comparable degree of sports experience were selected to take part in Pighin S et al. Acute Exercise & Risk Taking … Int J Sports Med 2015; 36: 858–863
Downloaded by: National University of Singapore. Copyrighted material.
Behavioural Sciences 859
the study. Participation criteria focused on: 1) type of sport (endurance sports: running, cycling and cross-country skiing); 2) the number of years of experience (between 5 and 7 years); 3) the number of weekly trainings (3 training sessions per week); 4) the duration of the training sessions (at least 2 h); 5) the number of season competitions (at least 5 competitions per season). Male and female samples significantly differed in their mean age: Males were older than females. Only amateur athletes holding a valid certificate of health status to practice competitive sports were eligible for the study. The study and the informed consent procedure were approved by the Research Ethics Committee of the University of Trento, in accordance with the international standards [27]. All participants were enrolled after written informed consent. All participants took part in 3 research phases, which were separated by a 7-day interval1. Phase 1 was aimed at familiarizing participants with the laboratory, the cognitive test designed to measure risk taking (i. e., the BART), and to estimate individual maximal aerobic power through a submaximal cycle ergometer test. Subjects underwent a three-step test of 80, 120 and 160 watts [3]. During this test, we monitored heart rate (HR) (using a Polar Electro Oy, Kempele, Finland) and oxygen uptake (VO2) (using a Quark b2, Cosmed s. r. l., Rome, Italy). Using the agepredicted maximal heart rate [45], due to the known linear relationship between HR and VO2, maximal oxygen consumption of each subject was estimated [56]. Then, using the ratio of VO2 to power during moderate effort, we calculated 60 % of the VO2 max (individual maximum aerobic capacity) and the corresponding power output necessary for Phase 2. Phase 2 resembled Phase 1 with respect to physical exercise: participants were required to warm up for 5 min on the cycle ergometer, gradually increasing exertion intensity until they reached 60 % of their individual VO2 maximum (measured in phase 1). When the required intensity was reached, participants continued to ride for 50 min. After the first 45 min (5 min of warming up and 40 min of exercise at the required intensity), participants were asked to perform the risk-taking task, while exercising. Phase 3 corresponded to the control session, at rest. In order to keep the 2 sessions exactly comparable, participants were required to sit on the cycle ergometer for 45 min without pedaling and then to perform the risk-taking task. Participants were simply instructed to wait and to feel free to think about whatever they preferred. The order of phases 2 and 3 was counterbalanced among participants. Laboratory room conditions were kept constant in all 3 phases, with an oxygen concentration of 20.9 %, a room temperature of 21 °C and absence of wind. 2 researchers were constantly present in the laboratory room during both the rest and the exercise sessions: a female researcher administered the BART and a male researcher recorded the physiological measurements. The task that participants were asked to perform was the BART [34]. In the game, participants have to inflate a series of 30 virtual balloons on a computer screen, accumulating money (i. e., 0.01 for each pump) each time they pump up the balloon. The objective of the task is to get the largest amount of money possible while avoiding balloon explosions. The probability of explosion of each balloon increased with the number of pumps and the explosion of the balloon determined the loss of the money accumulated in that balloon. Participants were free to 1
The data reported are part of a larger study aimed at examining the effect of exercise and oxygen depletion on athletes’ cognitive performance.
Pighin S et al. Acute Exercise & Risk Taking … Int J Sports Med 2015; 36: 858–863
choose when to stop pumping up balloons. When participants were satisfied with the amount of money collected in a given balloon, they could stop pumping and transfer the accumulated money to a “bank”. At the conclusion of the task, participants were given the amount of money earned. The mean payment was € 11.4. The task was displayed on a computer screen placed in front of the ergometer. The size of the computer screen, the distance between the participant and screen itself, and the placement of the response buttons on the handlebars were pretested in order to facilitate the visualization and the execution of the task. In order to check the effectiveness of the experimental manipulation, 3 physiological parameters were collected during each experimental session: heart rate (HR, using a Polar Electro Oy, Kempele, Finland), oxygen arterial saturation (SaO2, using a portable pulsoximeter from Intermed SAT-500), and blood lactate concentration (Biosen C-Line Sport Analyser EKF Diagnostics, Magdeburg, Germany). While HR was recorded in 5-s intervals during the whole experimental session, SaO2 and blood lactate levels were measured at 3 points in time: At the beginning of the physical exercise (approximately 10 min after entrance in the laboratory room), 10 min after the beginning of the exercise, and 30 min after the beginning of the exercise. In order to prevent a possible health risk for the participants, HR and SaO2 were continuously monitored by the (male) experimenter mentioned previously. At the end of each experimental session, participants were required to answer a subjective feeling questionnaire (see ● ▶ Table 1, previously used by 42–43), and the Positive and Negative Affect Schedule (PANAS – [57]).
Results
▼
Manipulation checks
Participants’ mean heart rate, oxygen arterial saturation and blood lactate levels are reported in ● ▶ Table 2. As predicted, participants’ physiological parameters significantly changed among experimental sessions. Participants demonstrated significantly higher HRs in the exercise session [mean = 152.2] with respect to the rest session [mean = 74.5; respectively, t(19) = − 32.2, p
Acute Exercise Increases Sex Differences in Amateur Athletes’ Risk Taking
Authors
S. Pighin1, 2, L. Savadori3, N. Bonini3, L. Andreozzi3, A. Savoldelli1, F. Schena1, 4
Affiliations
1
Key words ▶ physical exercise ● ▶ athletes ● ▶ decision making ● ▶ risk taking ● ▶ sex differences ●
Abstract
University of Verona, Research Center “Sport, Mountain and Health”, Trento, Italy Center for Experimental Research in Management and Economics, DCP, University IUAV of Venice, Venice, Italy 3 Department of Economics and Management, University of Trento, Trento, Italy 4 Neurological and Motor Science, University of Verona, Verona, Italy
▼
The research presented here investigates the interaction between acute exercise, biological sex and risk-taking behavior. The study involved 20 amateur athletes (19–33 years old), 10 males and 10 females, who were asked to undergo subsequent experimental sessions designed to com-
Introduction
▼
accepted after revision January 13, 2015 Bibliography DOI http://dx.doi.org/ 10.1055/s-0034-1398677 Published online: June 19, 2015 Int J Sports Med 2015; 36: 858–863 © Georg Thieme Verlag KG Stuttgart · New York ISSN 0172-4622 Correspondence Stefania Pighin, Phd Research Center “Sport, Mountain and Health” University of Verona Via Matteo del Ben 5/B, 38068 Trento Italy [email protected]
A substantial body of literature has investigated how physiological responses to acute exercise affect human behavior and cognition for a recent meta-analysis see [14]. Whereas the general issue of whether acute exercise has a beneficial or a detrimental effect on cognitive performances is still debated, there is substantial agreement that the effect of acute exercise on cognitive performance is strictly dependent on the nature of the cognitive task involved. Acute exercise seems to have a considerable positive effect on motor skills, reaction times and academic achievements [58] but negative effects on reasoning and verbal skills [24], on memory [25, 63] and on executive functions or frontal-lobe dependent measures [12, 13, 19, 20, 49, 59]. The cognitive task type is one of the primary moderators of the effect of acute exercise on cognition, along with the exercise intensity, the time of the cognitive test administration and the individual fitness level [14]. Interestingly, very few studies have investigated the effect of acute exercise on complex cognitive functions [14] and, to the best of our knowledge, no research has previously examined risk-taking behavior during an exercise session. Physical exercise is assumed to influence the cerebral systems associated with pleasure and mood regulation, increasing dopamine activation in critical sub-cortical brain regions [21, 47]. Among other
Pighin S et al. Acute Exercise & Risk Taking … Int J Sports Med 2015; 36: 858–863
pare their risky behaviors on the Balloon Analogue Risk Task (BART) [34] at rest and while exercising at moderate intensity (60 % of their maximal aerobic power). Results showed that physical exercise affected male and female participants differently: Whereas males became more risk seeking, females became more risk averse during exercise.
things, dopamine is recognized as a factor affecting risk-taking behaviors due to the activation of brain regions that are associated with novelty seeking and reward processing [22, 46, 61]. Neurobiological evidence suggests that acute exercise may affect risk propensity due to the resulting increase in dopamine production [19], which has been associated with an increase in risk taking [22, 61]. Therefore, we would expect to observe increased risk-taking behavior during exercise. Additional insights regarding the effect of exercise on risk taking can be found in the literature on acute stress. Indeed, the link between a single session of acute exercise and acute stress is well recognized [6]: the physiological changes induced by exercise (e. g., increased heart rate, increased respiratory rate, increased blood pressure, sweating, etc.) are observed under physically stressful conditions (as well as in states of high arousal). During moments of exercise and/ or acute stress, levels of adrenaline and noradrenaline increase in blood plasma and produce similar effects in the central nervous system [15]. The few existing studies relating acute stress to decision making indicate that acute stress can temporarily alter individual decisional behavior, particularly when decisions involve weighing risks vs. rewards [39, 42–45, 52]. Acute stress elicits automatic responses incorporating little cognitive reflection and is associated with a predominantly negative effect on decisional pro-
Downloaded by: National University of Singapore. Copyrighted material.
2
cesses for a review see [53]. Risk taking is a special case within decision-making behavior. Different definitions of risk taking exist and lead to differing approaches to the study of risk taking [48]. One preferred laboratory approach uses incentivized tasks to elicit individual risk preferences and to assess risk attitudes relevant in real-world settings by ascertaining behavioral responses to a real opportunity to win a certain amount of money see [9]. The Balloon Analogue Risk Task (BART) [34], for example, is a standard incentivized task that models real-world risk behavior in the context of balancing potential reward and harm [31, 34] in a dynamic learning environment (individuals receive an immediate feedback as in many real-world choices). Several psychometric works have suggested that the BART has reasonable measurement properties, including construct validity and test-retest reliability [32, 62], and that it is a valid and strong predictor of risk-taking behavior in different real-world risky domains. In this task, participants pump, repeatedly, a virtual balloon without knowing when it will explode. Each pump increases the potential reward but also the probability of explosion, which, if it occurs, wipes out all potential gains for that trial. Balloon explosion probabilities are drawn from a uniform distribution, and participants must learn explosion probabilities through trial-and-error. Previous research has supported the validity of this task and demonstrated a strong relationship with a wide range of maladaptive risky behaviors occurring outside the laboratory. An increased risk taking on the BART, for example, was found to be significantly related to drug and alcohol use, gambling, smoking, aggression, stealing and unprotected sexual behaviors [1, 33, 35]. In general, evidence indicates that males are more likely to engage in risky behavior see [8], such as alcohol and drug abuse [28, 51], risky investment decisions [16, 29, 54] and fatal car accidents [40]. Laboratory tasks using monetary gambles have also indicated that males are greater risk takers than females for a review see [34], and risk-taking behavior on the BART proves no exception see, e. g., [34]. In an attempt to explain sex differences in risk-taking behavior, an evolutionary account has been proposed. The parental investment theory [60] implies that men compete with one another over mating opportunities, suggesting that sex differences in risk-taking may be the product of male’s high degree of competition during mating [23]. Risk-taking among men can signal particular traits to women and to other men [2]. Risky behaviors among men, for example, have the potential of displaying to potential mates characteristics such as social dominance, confidence, ambition, skill and mental acuity, all of which are highly desired by women seeking a romantic partner [5, 36, 50]. Males therefore would demonstrate a pattern of greater risk-taking behavior compared to females, especially after anger induction [17, 18] because this trait has been historically preferred during mating competition. In summary, both stress and the sex of the participant appear to impact risk-taking behavior independently. However, there is evidence that sex differences and stress might affect risk taking jointly, as well. When the effect of stress on risk taking has been measured, differences between the sexes have been observed. Stress has been shown to increase risk taking in males and decrease risk taking in females [37]. This result was recently supported by brain imaging evidence: Stress has been shown to have opposite effects on brain activation and behavior for males and females [38]. Specifically, under stress, evidence has shown that males have an increased activation of the dorsal striatum and of the anterior insula, whereas females have a decreased
activation of the same areas. These areas are assumed to be related to decisional and reward processing, and their differential activation seemed to lead to different behaviors: Under stress, males were more sensitive to rewards while females were less sensitive [38]. Lighthall and colleagues [37] referred to evolutionary principles to explain this result. While the fight-orflight response [11] is considered the primary physiological response to stress for both males and females due to its self-survival relevance, some authors suggested the females’ stress responses could be marked by a pattern termed “tend-tobefriend”, focused on maximizing the survival of self and offspring. Such response would involve protection behaviors, the reduction of neuroendocrine responses that may compromise one’s own and the offspring’s health, and affiliating behaviors in order to reduce risks [55]. In line with Taylor and colleagues’ theory [55], the pressure imposed by natural selection seems to be reflected in different behavioral responses to stress in males and females. Males’ tendency to be more risk seeking under stress in laboratory conditions would be analogous to the “fight” response showed by our ancestors in competitive situations. In contrast, females’ tendency to be more risk averse under stress in laboratory conditions would be analogous to the beneficial, conservative and protective “tend-to-befriend” response showed by our female ancestors. Sex differences in stress responses may be rooted in differential neuroendocrine mechanisms: acute stress increases testosterone in males, which is a good predictor of aggressive responses in stressful situations [26], while it increases oxytocin in females, which seems to have a calming effect [10, 41]. Despite the fact that such differences in neuroendocrine responses could reflect differential selection pressure and reproductive behaviors, the interaction between stress, biological sex and risk taking is still under investigation. The premise underlying the present study was that physiological changes in response to physical exercise may influence risktaking behaviors, having different effects in males and females. The goal of the present research was thus to examine the effect of acute physical exercise on risk-taking behavior in males and females. Our prediction is that acute exercise increases sex differences in risk taking: we expect acute exercise to increase risk taking in males and decrease risk taking in females. To test for this prediction the BART [34] was chosen as the dependent measure for (at least) 2 reasons. First, performances on the BART represent a reliable indication of individuals’ attitude toward risky behaviors, as they correlate with several behaviors related to addiction, safety and health [1, 32, 35]. Second, previous studies have shown greater risk-taking behavior in males and smaller risk-taking behavior in females under stress on the BART [37].
Materials & Method
▼
A sample of 20 amateur athletes volunteered to participate in the study: 10 males (mean age = 25.7 ± 3.9) and 10 females (mean age = 21.2 ± 1.83), who regularly practice sport at the amateur level, with a comparable degree of sports experience. Participants were recruited by contacting local sport associations and teams. They were invited to take part in a research project on the effect of exercise on decision making. All volunteers were required to fill out a questionnaire concerning their activity (e. g., number of weekly training sessions, duration of training, number of seasonal competitions, etc.). Participants with a comparable degree of sports experience were selected to take part in Pighin S et al. Acute Exercise & Risk Taking … Int J Sports Med 2015; 36: 858–863
Downloaded by: National University of Singapore. Copyrighted material.
Behavioural Sciences 859
the study. Participation criteria focused on: 1) type of sport (endurance sports: running, cycling and cross-country skiing); 2) the number of years of experience (between 5 and 7 years); 3) the number of weekly trainings (3 training sessions per week); 4) the duration of the training sessions (at least 2 h); 5) the number of season competitions (at least 5 competitions per season). Male and female samples significantly differed in their mean age: Males were older than females. Only amateur athletes holding a valid certificate of health status to practice competitive sports were eligible for the study. The study and the informed consent procedure were approved by the Research Ethics Committee of the University of Trento, in accordance with the international standards [27]. All participants were enrolled after written informed consent. All participants took part in 3 research phases, which were separated by a 7-day interval1. Phase 1 was aimed at familiarizing participants with the laboratory, the cognitive test designed to measure risk taking (i. e., the BART), and to estimate individual maximal aerobic power through a submaximal cycle ergometer test. Subjects underwent a three-step test of 80, 120 and 160 watts [3]. During this test, we monitored heart rate (HR) (using a Polar Electro Oy, Kempele, Finland) and oxygen uptake (VO2) (using a Quark b2, Cosmed s. r. l., Rome, Italy). Using the agepredicted maximal heart rate [45], due to the known linear relationship between HR and VO2, maximal oxygen consumption of each subject was estimated [56]. Then, using the ratio of VO2 to power during moderate effort, we calculated 60 % of the VO2 max (individual maximum aerobic capacity) and the corresponding power output necessary for Phase 2. Phase 2 resembled Phase 1 with respect to physical exercise: participants were required to warm up for 5 min on the cycle ergometer, gradually increasing exertion intensity until they reached 60 % of their individual VO2 maximum (measured in phase 1). When the required intensity was reached, participants continued to ride for 50 min. After the first 45 min (5 min of warming up and 40 min of exercise at the required intensity), participants were asked to perform the risk-taking task, while exercising. Phase 3 corresponded to the control session, at rest. In order to keep the 2 sessions exactly comparable, participants were required to sit on the cycle ergometer for 45 min without pedaling and then to perform the risk-taking task. Participants were simply instructed to wait and to feel free to think about whatever they preferred. The order of phases 2 and 3 was counterbalanced among participants. Laboratory room conditions were kept constant in all 3 phases, with an oxygen concentration of 20.9 %, a room temperature of 21 °C and absence of wind. 2 researchers were constantly present in the laboratory room during both the rest and the exercise sessions: a female researcher administered the BART and a male researcher recorded the physiological measurements. The task that participants were asked to perform was the BART [34]. In the game, participants have to inflate a series of 30 virtual balloons on a computer screen, accumulating money (i. e., 0.01 for each pump) each time they pump up the balloon. The objective of the task is to get the largest amount of money possible while avoiding balloon explosions. The probability of explosion of each balloon increased with the number of pumps and the explosion of the balloon determined the loss of the money accumulated in that balloon. Participants were free to 1
The data reported are part of a larger study aimed at examining the effect of exercise and oxygen depletion on athletes’ cognitive performance.
Pighin S et al. Acute Exercise & Risk Taking … Int J Sports Med 2015; 36: 858–863
choose when to stop pumping up balloons. When participants were satisfied with the amount of money collected in a given balloon, they could stop pumping and transfer the accumulated money to a “bank”. At the conclusion of the task, participants were given the amount of money earned. The mean payment was € 11.4. The task was displayed on a computer screen placed in front of the ergometer. The size of the computer screen, the distance between the participant and screen itself, and the placement of the response buttons on the handlebars were pretested in order to facilitate the visualization and the execution of the task. In order to check the effectiveness of the experimental manipulation, 3 physiological parameters were collected during each experimental session: heart rate (HR, using a Polar Electro Oy, Kempele, Finland), oxygen arterial saturation (SaO2, using a portable pulsoximeter from Intermed SAT-500), and blood lactate concentration (Biosen C-Line Sport Analyser EKF Diagnostics, Magdeburg, Germany). While HR was recorded in 5-s intervals during the whole experimental session, SaO2 and blood lactate levels were measured at 3 points in time: At the beginning of the physical exercise (approximately 10 min after entrance in the laboratory room), 10 min after the beginning of the exercise, and 30 min after the beginning of the exercise. In order to prevent a possible health risk for the participants, HR and SaO2 were continuously monitored by the (male) experimenter mentioned previously. At the end of each experimental session, participants were required to answer a subjective feeling questionnaire (see ● ▶ Table 1, previously used by 42–43), and the Positive and Negative Affect Schedule (PANAS – [57]).
Results
▼
Manipulation checks
Participants’ mean heart rate, oxygen arterial saturation and blood lactate levels are reported in ● ▶ Table 2. As predicted, participants’ physiological parameters significantly changed among experimental sessions. Participants demonstrated significantly higher HRs in the exercise session [mean = 152.2] with respect to the rest session [mean = 74.5; respectively, t(19) = − 32.2, p
