Gender Differences in Carbohydrate Loading
J Appl Physiol 91: 225–230, 2001.
Gender differences in carbohydrate loading are related to energy intake
MARK A. TARNOPOLSKY,1,2 CAROL ZAWADA,2 LINDSAY B. RICHMOND,2 SHERRY CARTER,1 JANE SHEARER,3 TERRY GRAHAM,3 AND STUART M. PHILLIPS2 1 Departments of Medicine (Neurology and Rehabilitation) and 2Kinesiology, McMaster University, Hamilton, Ontario L8N 3Z5; and 3Human Biology and Nutrition, University of Guelph, Guelph, Ontario, Canada N1G ZW1
Received 5 July 2000; accepted in final form 6 April 2001
Tarnopolsky, Mark A., Carol Zawada, Lindsay B. Richmond, Sherry Carter, Jane Shearer, Terry Graham, and Stuart M. Phillips. Gender differences in carbohydrate loading are related to energy intake. J Appl Physiol 91: 225–230, 2001.—We demonstrated that female endurance athletes did not increase their muscle glycogen concentration after an increase in the dietary carbohydrate intake (58 3 74%), whereas men did (Tarnopolsky MA, SA Atkinson, SM Phillips, and JD McDougall, J Appl Physiol 78: 1360–1368, 1995). This may have been related to a lower energy or carbohydrate intake by the women or due to an inherent gender difference in glycogen storage capacity. We examined whether well-trained men (n 6) and women (n 6) increased muscle glycogen concentration after an increase in both the relative (58 3 75%) and absolute energy and carbohydrate intake and whether potential gender differences were related to muscle hexokinase enzyme activity. Subjects were randomly allocated to three diets [Hab, habitual; CHO, high carbohydrate (75%); and CHO E, extra energy CHO (1 34%)] for a 4-day period before a muscle biopsy for analysis of total and pro- and macroglycogen and hexokinase activity. Total glycogen concentration was higher for the men on the CHO and CHO E trials compared with Hab (P 0.05), whereas women increased only on the CHO E trial compared with Hab (P 0.05). There were no gender differences in the proportion of pro- and macroglycogen or hexokinase activity. A low
Gender differences in carbohydrate loading are related to energy intake
MARK A. TARNOPOLSKY,1,2 CAROL ZAWADA,2 LINDSAY B. RICHMOND,2 SHERRY CARTER,1 JANE SHEARER,3 TERRY GRAHAM,3 AND STUART M. PHILLIPS2 1 Departments of Medicine (Neurology and Rehabilitation) and 2Kinesiology, McMaster University, Hamilton, Ontario L8N 3Z5; and 3Human Biology and Nutrition, University of Guelph, Guelph, Ontario, Canada N1G ZW1
Received 5 July 2000; accepted in final form 6 April 2001
Tarnopolsky, Mark A., Carol Zawada, Lindsay B. Richmond, Sherry Carter, Jane Shearer, Terry Graham, and Stuart M. Phillips. Gender differences in carbohydrate loading are related to energy intake. J Appl Physiol 91: 225–230, 2001.—We demonstrated that female endurance athletes did not increase their muscle glycogen concentration after an increase in the dietary carbohydrate intake (58 3 74%), whereas men did (Tarnopolsky MA, SA Atkinson, SM Phillips, and JD McDougall, J Appl Physiol 78: 1360–1368, 1995). This may have been related to a lower energy or carbohydrate intake by the women or due to an inherent gender difference in glycogen storage capacity. We examined whether well-trained men (n 6) and women (n 6) increased muscle glycogen concentration after an increase in both the relative (58 3 75%) and absolute energy and carbohydrate intake and whether potential gender differences were related to muscle hexokinase enzyme activity. Subjects were randomly allocated to three diets [Hab, habitual; CHO, high carbohydrate (75%); and CHO E, extra energy CHO (1 34%)] for a 4-day period before a muscle biopsy for analysis of total and pro- and macroglycogen and hexokinase activity. Total glycogen concentration was higher for the men on the CHO and CHO E trials compared with Hab (P 0.05), whereas women increased only on the CHO E trial compared with Hab (P 0.05). There were no gender differences in the proportion of pro- and macroglycogen or hexokinase activity. A low
References: 1. Adamo KB and Graham TE. Comparison of traditional measurements with macroglycogen and proglycogen analysis of muscle glycogen. J Appl Physiol 84: 908–913, 1998. 2. Adamo KB, Tarnopolsky MA, and Graham TE. Dietary carbohydrate and postexercise synthesis of proglycogen and macroglycogen in human skeletal muscle. Am J Physiol Endocrinol Metab 275: E229–E234, 1998. 3. Bergstrom J, Hermansen L, Hultman E, and Saltin B. Diet, muscle glycogen and physical performance. Acta Physiol Scand 71: 140–150, 1967. 4. Burke LM and Hawley JA. Carbohydrate and exercise. Curr Opin Clin Nutr Metab Care 2: 515–520, 1999. 5. Ellis GS, Lanza-Jacoby S, Gow A, and Kendrick ZV. Effects of estradiol on lipoprotein lipase activity and lipid availability in exercised male rats. J Appl Physiol 77: 209–215, 1994. 6. Friedlander AL, Casazza GA, Horning MA, Huie MJ, Piacentini MF, Trimmer JK, and Brooks GA. Training-induced alterations of carbohydrate metabolism in women: women respond differently from men. J Appl Physiol 85: 1175–1186, 1998. 7. Gauthier JM, Theriault R, Theriault G, Gelinas Y, and Simoneau JA. Electrical stimulation-induced changes in skeletal muscle enzymes of men and women. Med Sci Sports Exerc 24: 1252–1256, 1992. 8. Green HJ, Fraser IG, and Ranney DA. Male and female differences in enzyme activities of energy metabolism in vastus lateralis muscle. J Neurol Sci 65: 323–331, 1984. 9. Hansen PA, McCarthy TJ, Pasia EN, Spina RJ, and Gulve EA. Effects of ovariectomy and exercise training on muscle GLUT-4 content and glucose metabolism in rats. J Appl Physiol 80: 1605–1611, 1996. 10. Horton TJ, Pagliassotti MJ, Hobbs K, and Hill JO. Fuel metabolism in men and women during and after long-duration exercise. J Appl Physiol 85: 1823–1832, 1998.