433
Fat Storage in Athletes: Metabolic and Hormonal Responses to Swimming and Running M G. Flynn, D. L. Costill, J. P. Kirwan, J. B. Mitchell, .1. A. Hournard, W. J. Fink, J. D. Beltz andL. J. D'Acquisto Human Performance Laboratory, Ball State University, Muncie, IN 47306
M G. Flynn, D. L. Costill, I P. Kirwan, I B. Mitchell, J. A. Houmard, W. I Fink, I D. Beltz and L. J. D'Acquisto, Fat Storage in Athletes: Metabolic and Hormonal Responses to Swimming and Running. Tnt J Sports Med,Vol 1 1,No6,pp433—440, 1990.
Accepted after revision: February 19, 1990
Despite similar rates of energy expenditure during training, it has been suggested that swimmers store greater amounts of body fat than runners. To investigate these discrepancies, eight male swimmers (5) and runners (R) were monitored during 45 mm of swimming or running (75% VO2max), respectively, and six triathietes were monitored during swimming (ST) and running (RT). Each group was also monitored during two hours of recovery. Venous blood samples were obtained before exercise, immediately after exercise (0 mm) and at 15, 30, 60 and 120 mm of recovery. These samples were analyzed for glucose, lactate, glycerol, free fatty acids (FFA), insulin, glucagon, norepinephrine (NE) and epinephrine (E). Expired gases and heart rates (HR) were obtained during exercise and also during re-
Introduclion
Competitive swimmers are reported to have greater relative body fat stores than competitive runners (16, 19, 31, 34). This difference is difficult to explain since the caloric expenditure during training for competitive swimmers
covery. The caloric cost of recovery was similar, but the RER results suggested increased fat oxidation during recovery for the S and the ST. Serum glucose was greater (P
Fat Storage in Athletes: Metabolic and Hormonal Responses to Swimming and Running M G. Flynn, D. L. Costill, J. P. Kirwan, J. B. Mitchell, .1. A. Hournard, W. J. Fink, J. D. Beltz andL. J. D'Acquisto Human Performance Laboratory, Ball State University, Muncie, IN 47306
M G. Flynn, D. L. Costill, I P. Kirwan, I B. Mitchell, J. A. Houmard, W. I Fink, I D. Beltz and L. J. D'Acquisto, Fat Storage in Athletes: Metabolic and Hormonal Responses to Swimming and Running. Tnt J Sports Med,Vol 1 1,No6,pp433—440, 1990.
Accepted after revision: February 19, 1990
Despite similar rates of energy expenditure during training, it has been suggested that swimmers store greater amounts of body fat than runners. To investigate these discrepancies, eight male swimmers (5) and runners (R) were monitored during 45 mm of swimming or running (75% VO2max), respectively, and six triathietes were monitored during swimming (ST) and running (RT). Each group was also monitored during two hours of recovery. Venous blood samples were obtained before exercise, immediately after exercise (0 mm) and at 15, 30, 60 and 120 mm of recovery. These samples were analyzed for glucose, lactate, glycerol, free fatty acids (FFA), insulin, glucagon, norepinephrine (NE) and epinephrine (E). Expired gases and heart rates (HR) were obtained during exercise and also during re-
Introduclion
Competitive swimmers are reported to have greater relative body fat stores than competitive runners (16, 19, 31, 34). This difference is difficult to explain since the caloric expenditure during training for competitive swimmers
covery. The caloric cost of recovery was similar, but the RER results suggested increased fat oxidation during recovery for the S and the ST. Serum glucose was greater (P
