Eating and Training with the Menstrual Cycle

Many people know and can appreciate that the menstrual cycle plays a huge role in women’s lives. Although, many people don’t know the extent that our hormones affect our daily moods, energy levels, tolerance with exercise, and nutrition needs. My goal is to give you a brief understanding of how our hormones fluctuate during the menstrual cycle and what that means for exercise and nutrition needs for women. I recently learned from Dr. Stacy Sims, an exercise physiologist and nutrition scientist, that most of the research on nutrition and exercise is done on males. Many studies in the literature today that do involve females have looked at the responses of females with diet/exercise during the first half of their cycle, when their hormones are most similar to men. This is something that, in my opinion, is very concerning as women and men are extremely different and should not be treated the same in regard to exercise and nutrition needs. Before we dig deeper into this, let’s discuss a basic overview of the menstrual cycle. 

Menstrual Cycle Overview: 

The menstrual cycle lasts about 24-32 days, and differs from woman to woman. It can be as short as 21 days and as long as 40 days. The cycle starts on day one of menstruation and about halfway through (~ day 14) is when ovulation occurs. We will discuss the cycle in phases. The first phase being the follicular phase and the second phase, occurring after ovulation, is the luteal phase. Our hormones fluctuate during these phases and therefore will affect our tolerance with exercise and nutrition needs. One little caveat here is that these hormone changes are apparent in women who have not gone through menopause and women who are not on an oral birth control.

Follicular Phase: 

During the first half of our cycle, from day one of menstruation to ovulation day (~days 14), our hormones are most similar to men. As you can see in the chart above during this phase, the follicular phase, our estrogen and progesterone are all relatively low and stagnant. Due to these lower levels in female hormones, the body can withstand much harder training efforts. Our body is able to access carbohydrates better to use as fuel. We also are able to build muscle with greater ease during this phase of the cycle. 

With that being said, we can bias our training to try to hit higher intensity workouts or lift greater loads during this period. It will allow us to better build up strength and aerobic capacity by pushing hard in this phase. Our nutrition needs don’t differ much in this phase, but it is crucial that we are getting enough carbohydrates for energy and protein for muscle building. Carbohydrate intake will differ for everyone based on size and activity level, but in regard to protein, it is recommended that we try to hit a goal of 1 gram of protein/lb body weight. 

Luteal Phase. 

During the luteal phase, the second half of our cycle, we see an increase in our estrogen and progesterone. These hormones affect every system in our body, which can affect our energy levels, stress levels, inflammation levels, and more. 

This increase in hormone levels puts our body into a catabolic state, meaning a state of the breakdown tissues. This can reduce our muscle-building capacity. It also makes it more challenging to access stored carbohydrates for fuel. With all that being said, we may not be able to tolerate pushing ourselves as much during high intensity training or lift as heavy during this phase, but we also need to increase our caloric intake, especially with carbohydrates in this phase in order to adequately fuel our body. Dr. Sims recommended an increase in protein intake to about 1.2 grams of protein per lb of body weight at this time as well. 

Conclusion

Knowing where women are during the menstrual cycle can give us a huge advantage for many reasons. It will explain why our energy levels might be off, why fatigue may set in faster during a HIIT workout, or it may even explain why we unexpectedly hit a PR during a lift. It can be extremely beneficial to first track the cycle and get familiar with the different phases. Second, be aware that we can push ourselves a little harder during a run or put a little more weight on the bar during a lift during the first half of our cycle, whereas, we may need to tone it down a bit during the second half of our cycle. Third, it is crucial to make sure we hit our caloric and nutritional needs throughout the cycle, but we should increase our carbohydrate and protein intake during the second phase of our cycle in order to make up for all of the breakdown that is occurring in our body at this time. 

Please don’t hesitate to reach out if you have any questions or concerns with any of the information in this article. If you would like to dive deeper into your nutrition needs, I recommend seeking out advice from a sports nutritionist or dietitian. If you would like further advice on exercise needs or if you are dealing with any nagging injuries, we would love to work with you here at Athletic Edge Physical Therapy. If you’d like an in-person or virtual consult, please reach out to us, we’d love to hear from you! Text or call: 858-371-2575, or e-mail us at: info@athleticedgept.com.