Jacobs, I., Moroz, D., Tikuisis, P., & Vallerand, A. (2000). Muscle glycogen in females after exercise at 9 and 21 degrees Celsius. Medicine and Science in Sports and Exercise, 32(5), Supplement abstract 1684.

Female Ss (N = 13), divided into two groups, were used to compare the magnitude of change in skeletal muscle glycogen concentrations after light and moderate intensity exercises in both cold and comfortable temperatures. Groups were matched for submaximal exercise intensity corresponding to 4 mmol lactate threshold. On two occasions, Ss rested for 30 minutes at 9 or 21 degrees Celsius, at the end of which a biopsy of the vastus lateralis was taken. Light exercise consisted of 30 minutes at 30% of the 4 mmol lactate threshold while moderate exercise was 30 minutes at 60%. Ss performed at the same power output for both trials. Another biopsy was taken after each exercise.

Oxygen uptake was significantly higher (12%) in the cold condition, but not in the moderate condition. Muscle glycogen decreased significantly in the moderate condition but not in the cold. Temperature did not affect the magnitude of the change in muscle glycogen.

Females had a more pronounced lipid metabolism than males in extended exercise.

Implication. Females fuel aerobic exercise differently to males.

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