Nutrition, Exercise, & the Menstrual Cycle
While the menstrual cycle causes multiple physiological changes in the female, its influence on exercise performance or need for appropriate dietary changes to meet hormonal needs is still being explored.
In a recent study a significant number of female competitive endurance athletes reported their performance was altered by their menstrual cycle. Worst performance was reported by 30% of females analyzed, and worst fitness by 47%, during menses. The best perceived performance and fitness was noted in the early follicular phase (immediately following menses). Very few (8%) reported confidence or knowledge in correlating training with their menstrual cycle.
The menstrual cycle is controlled by the hypothalamus-pituitary-ovarian axis. The average cycle in a healthy woman is roughly 21-35 days in length. The cycle involves follicular development, ovulation, growth of the endometrium, and menses (excretion of the endometrium) if implantation does not occur.
The cycle is divided into two phases, follicular (development of the follicle) and luteal (formation of the corpus luteum). Estrogen and progesterone are the main contributors to the menstrual cycle and reproductive function.
During menses (the start of the cycle), estrogen and progesterone are at their lowest. As the cycle progresses into the early follicular phase estrogen levels begin to rise. At ovulation (late follicular phase), estrogen levels drop, followed by both progesterone and estrogen rising. In the luteal phase, if implantation does not occur, both estrogen and progesterone drop.
It is generally believed that estrogen improves exercise performance while progesterone acts antagonistically.
Early Follicular Phase
In the early follicular phase when estrogen is high, women generally experience an increase in positivity and alertness due to increased serotonin and brain serotonin receptors.
Energy levels are higher while appetite is decreased. Muscle recovery and adaptation from intense training is at its peak due to estrogen’s antioxidant capacity.
Glycogen storage capacity, however, is lower during this phase. Therefore, there is an increased need for carbohydrates during training. It is particularly important to consume protein and carbohydrates as soon as possible after a workout.
Due to increased energy and focus, adaptation to high intensity and strength training is improved. Cognition and coordination peak during this phase.
Late Follicular Phase
Rising progesterone levels in the late follicular phase causes increased feelings of emotion and empathy, rise in body temperature, increased heart rate, increased insulin sensitivity, and increased fatigue.
Oxidative capacity may be improved during this phase so focusing on high intensity aerobic exercise may be beneficial. This is also a great time to focus on improving flexibility.
While there generally is a higher pain threshold during this phase, higher progesterone levels can make recovery slower.
A higher intake of carbohydrates continues to be necessary due to poor muscle glycogen storage. Consumption of complex carbohydrates and protein to help with cravings and mood disturbances is helpful.
Luteal Phase
In the luteal phase, there is a rise in prostaglandins associated with the drop in estrogen and progesterone. This leads to increased inflammation and premenstrual symptoms. Increased inflammation may reduce recovery ability.
Appetite, fatigue, and mood changes are often increased. Sleep can be disrupted. Increased levels of stress can worsen premenstrual symptoms.
There is an increased expression of vasopressin which results in water and sodium retention and an increase in blood pressure. A reduction in plasma volume, cardiac output, and perspiration are noted.
Glycogen storage capacity is at its peak, thus there is reduced reliance on muscle glycogen during exercise and an increase in free fatty acid availability.
An increase in insulin resistance and protein catabolism is also seen during this phase. Therefore, protein and amino acid needs are increased during and around exercise.
Basal metabolic rate may be 5-10% increased.
Fats should be the primary fuel source, but complex carbohydrates and protein will help stabilize blood sugar levels. Fluid and electrolyte intake should be maximized.
Exercise-related injuries can be higher during the luteal phase, possibly due to greater postural sway and passive knee motion.
Eating less processed foods, and more anti-inflammatory, antioxidant foods will help with menstrual symptoms and inflammation.
Due to increased oxidative capacity, better moderate intensity endurance performance is seen during this phase. To decrease stress and PMS, include activities such as yoga and Pilates.
Menstrual
A sustained inflammatory response due to low hormone levels is seen during the menstrual phase. Exercise will continue to help with inflammation, mood, and PMS.
Recovery may be longer and neuromuscular control may be lower. Include muscle activation exercises in warmup. Maximum training benefit may come from strength training and HIIT. The ability to perform mental rotation tasks is improved.
The amount of white blood cells in the blood is lowest during this phase, increasing susceptibility to infection. Sleep and rest are key.
Focus on anti-inflammatory, antioxidant foods to help with menstrual symptoms. Increase carbohydrate consumption prior to long endurance effort and consume iron-rich foods along vitamin C.
Overall Nutritional Considerations for Women
· Loss of iron stores from menstruation
· Women tend to use fat more for energy metabolism during exercise than men
· There is data to indicate that females may have decreased absorption, utilization, and breakdown of consumed protein. Consequently, women have a higher need for protein, especially peri- and post-menopause. To learn more about the importance of protein for exercise and weight management: