Mastering the Menstrual Cycle as a Female Athlete

Thankfully, there has been increased research on how a woman's menstrual cycle impacts athletic performance and nutritional needs. As athletes and coaches, discussion around this topic needs to become more normalized so women everywhere can take control of their cycle and understand what is happening to their bodies throughout the month. 

The menstrual cycle has two phases - the follicular and luteal phases - and lasts between 26 to 35 days.Shifting hormone levels trigger the shift between phases (12, 16, 24). Follicle-stimulating hormone (FSH) produced in the brain signals an egg to mature within the ovaries. A cascade of events leads your ovaries to increase estrogen and progesterone production while decreasing FSH about a week into your cycle. Nearing halfway through your cycle, as estrogen levels increase, luteinizing hormone (LH) increases dramatically. This steep increase triggers a mature egg to leave the ovaries, which is known as ovulation and marks the end of the follicular phase and the beginning of the luteal phase. High progesterone and estrogen levels characterize the luteal phase to prepare for potential pregnancy, also known as fertilization (12, 16, 24). Fertilization is when the sperm and egg meet. The peak in hormones during this phase causes premenstrual syndrome (PMS) symptoms. If no pregnancy occurs, then progesterone and estrogen levels fall again. The fall in progesterone and estrogen triggers your lining to shed - your “time of the month” - and you are back to square one. (12, 16, 24) For this article, low-hormone days refer to your period and the days following. The high-hormone days refer to just before your period. 

Fluctuating hormones during your cycle can impact how you feel and perform. The good news is your hormones are on your side while you're on your period. If you don't get pregnant, your hormones rapidly decrease, and your body shifts to a more relaxed, steady state for a few days. During this time, women's physiology is almost like men's (24). Research shows low-hormone days, while you're on your period, can help with developing long-term strength and force production. Women feel less pain and can recover faster during this time of their cycle. On the other hand, the high-hormone days will make exercise and training feel harder. High-hormone days also make you feel hotter, can cause stomach problems, and make you feel moody, which can make your performance worse (6, 24, 28). It is more challenging for women to create and maintain muscle during this time of the month, too. This time of the month is great for focusing on cardiovascular training. Studies suggest that women's aerobic capacity (VO2 max) and lactate threshold stay consistent throughout the month. (24, 27 ,28). So although you may feel crummy at times, your endurance abilities remain consistent. As women get closer to menopause, they lose more muscle and power-producing abilities because our hormones are conducive to it. Changes in strength and power are due to a steady decrease in estrogen production during the years leading up to menopause (24).

The shift in our hormones makes maintaining strength and power more important as we age. Movements that involve large muscle groups (squats, pull-ups, bench press, etc.) are great for improving strength. Explosive movements (box jumps, hang-cleans, ball slams, etc.) are ideal for enhancing power production. Research suggests that high-intensity interval training (HIIT) and plyometrics (power training) are most appropriate to train during the follicular phase, during your period and the time following it. Muscle contractions are more forceful and fatigue-resistant during this time of the menstrual cycle. Enhanced muscle performance is due to lower amounts of estrogen, which is much higher during the luteal phase just before your period. (19, 28). Constant changes in hormones make women more susceptible to injuries during certain times of the month. Developing core stability and glute strength can help avoid lower-body injuries that women are more prone to (13, 14, 21, 28). Focusing on core stability is commonly associated with crunches and abs, yet they are not synonymous. Core exercises like planks, hollow body holds, etc., help create a stiff posture for the torso, which is ideal. Your glutes keep your pelvis and knee in an optimal position when jumping and running. It also assists the abdominal muscles and back in maintaining an upright posture. Hip extensions and lunges are good for improving strength and lower body stability. Injury prevention through training can help any woman stick to high levels of activity for longer!

You guessed it, a woman's hormone profile also impacts her nutrition and hydration needs. During higher-hormones times of your cycle, when it's more challenging to make and maintain muscle - thank you estrogen - it's imperative to consume protein (18). Women should consume protein high in leucine or branched-chain amino acids (BCAAs) right before and within 30 minutes after training. (24). You may notice your cravings change throughout the month too. Cravings are influenced by estrogen, which decreases your body's ability to burn carbs. Since estrogen increases as you get closer to your period, you may crave sweets. Estrogen's influence makes eating more carbs before your period important (8, 9, 24). Bloating is commonly associated with PMS. Our body's water content is influenced by estrogen and progesterone, making the body hold onto water more (25). 

Women have different hydration needs than men; this is again due to hormone influences on sodium and water changes and temperature changes (26, 28). Hydration should be an essential part of performance fueling before, during, and after training sessions and races/events. Hydration is a necessary part of proper body functioning, including blood movement throughout the body. When choosing sports drinks, sodium works best when it has glucose to help it out. Sodium is absorbed more efficiently and timely when it's paired with glucose. Drinking according to thirst is a good place to start; a woman's hormone profile can impact this efficiency. Drinking to thirst can work if it's a high-hormone day leading up to your period or if you're taking progesterone-based birth control (20, 22, 23, 24, 25). Drinking too much water can also lead to hyponatremia, also known as water intoxication. Potential hyponatremia and dehydration make monitoring your hydration levels more critical, especially as an athlete who trains for long periods and in hot temperatures. The recommendation is between .10 to .15 ounces of water per pound of body weight per hour. Athletes should lean toward the higher end of the advice for hotter temperatures. Drinking on a schedule is a better option if you have multiple training sessions a day or perform in a new environment (heat, altitude, etc.) (22, 24). In doubt, pee strips (urinalysis) are a cheap and effective way to monitor hydration, training stress, and recovery (3, 10, 15, 22, 24).

Hard work is only part of the process if you want to kick your athletics up a notch. Female athletes are 2 to8 times more likely to suffer knee injuries than males (2, 13, 14). Our changing hormones impact our connective tissues making them less supportive and more relaxed during certain times of our cycle, leading to higher injury risk. Less supportive tissue is especially true during ovulation when estrogen increases (1, 4, 21, 28). A woman's center of gravity and broader hips also contribute to injury risk (5). Addressing stability and mobility can help reduce these risks. There's a misconception about flexibility's role; being flexible isn't enough to prevent injuries. Mobility, moving through motions without being limited by stiffness, is optimum (17).  Cooling down after a training session helps bring blood lactate levels back to resting and prevents blood pooling in your legs. Easing out of exercise also helps get critical nutrients to your worked muscles to help with muscle repair. Active rest (easy walk or slow yoga), massage, and compression can help you recover faster. Active rest works by enhancing blood flow to bring nutrients to your muscles and breaking down adhesions or knots in your muscles (11, 29).

Female athletes should consider the following

• Period tracking is a great way to master your female anatomy. Apps are an excellent tool for this, including Ovia, MagicGirl, and Flo.
• Prioritize core stability and glute strength and maintain mobility as a part of your training regime to reduce your injury risk
• Include warm-ups, cool-downs, and active rest in your training
• Eat protein after you train to optimize muscle recovery.
• Hydrate with electrolyte mixtures that contain sodium and sugar (like Gnarly Hydrate), either on a schedule or by using pee strips.
• If you don’t have a regular period, it’s essential to talk to your doctor. Your menstrual cycle is a part of normal body function; without it, you’re placing yourself at risk.

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