Influence of the menstrual cycle on exercise performance

March 5, 2011 - PRLog -- Exercise performance is directly related to your body’s internal environment (homeostasis). There is evidence to suggest that the hormonal changes causing the menstrual cycle and affecting homeostasis will also affect physical performance in exercise.
Studies such as that of Hackney, Nicklas and Sharp (2001) found through biopsies in the Vastus Lateralis muscle that repletion of fuels (glycogen) within muscles during the latter Luteal Phase of the menstrual cycle was 12% higher than in the follicular phase. The more available the fuel for muscular contractions, the more likely that exercise performance will be increased.
When you exercise your breathing rate increases. This can be for two reasons which are not mutually exclusive. Either your body needs oxygen for fuel (aerobic respiration) or the carbondioxide byproduct are leading to increased acidity in your muscles which need increase expiration of gasses to normalise blood pH. Loeppkey, Scotto, Charlton, Gates, Icenogle and Roach (2000) found in their study that women normally have an increased rate of ventilation (inspiration/ expiration) than men due to higher levels of acidity within the blood which is further increase by progesterone in the Luteal phase of the menstrual cycle. Consistently elevated expiration of carbon dioxide creates a pH imbalance towards hyper alkalinity. The more alkali the blood, the more oxygen is available for absorption, further perpetuating performance in aerobic activities.
It could be suggested then that the most successful exercise performances for women could exist in those who are experiencing the Luteal Phase of their menstrual cycle i.e. days 14-28.
For more information about exercise, health and women’s fitness visit www.merseysidebootcamp.co.uk or www.pbfit.co.uk/blog

Steve Cooper
PB Fitness
Rainhill Bootcamp

References:

Loeppkey, J., Scotto, P., Charlton, G., Gates, L., Icenogle, M., Roach, R. (2000) Ventilation is greater in women than men, but the increase during acute altutude hypoxia is the same. Respiration Physiology 125;3;225-237.
Swedan, N. (2001) Women’s Sports Medicine and Rehabilitation. USA: Aspen Publishers Inc.