How your cycle impacts your exercise

If you menstruate, your physiology is different from those who don’t. ⁠So doesn’t it make sense that menstruating people would need to train differently to get to their fitness goals? The unfortunate truth is that up until recently, this fact has been largely ignored in fitness and health research - which is often done exclusively on non-menstruators to eliminate the variability of hormonal fluctuations initiated by the menstrual cycle.

What if I told you that your monthly hormone changes aren’t an obstacle but rather an opportunity. An opportunity to leverage the phases of your cycle to your advantage. See, if you can understand your hormones and the way they relate to your physiology, you can learn to work WITH your body instead of AGAINST it. 

First a quick reminder about the phases of the menstrual cycle. A new menstrual cycle starts with the first day of your period. This is the early follicular phase, and at this time both estrogen and progesterone are low. Estrogen levels start to climb by about day 3 of your period, and continue to rise until ovulation, when the follicular phase ends. Ovulation is triggered by a spike and then drop off in hormones. After this the luteal phase begins, in which estrogen again rises this time along with progesterone. When these hormones fall, your next period begins.

These natural fluctuations in hormones have the ability to drastically change your energy, your mood, and your exercise performance. That’s right, it is not just in your head that workouts feel more challenging during certain times of the month! Hormone changes affect the fuels that you burn (fat vs carbohydrate), your fluid distribution (which impacts your ability to sweat), your heat tolerance, your mood and more. Now I’m going to break it down for you in terms of what happens during each phase of the menstrual cycle and what this may mean for tweaking your exercise plans to feel your best. 

FOLLICULAR PHASE

The follicular phase encompasses your period and the days that follow until ovulation. While many people intuitively think their performance is going to decline while they are on their period, this is actually a prime time for exertion. Studies have shown that swimmers clock faster times on their period than during the premenstrual phase. If you think about it, your body has just realized that pregnancy didn’t occur - hence menstruation. This means that all your body's energy stores are available, as opposed to being stored away for a possible pregnancy. Estrogen and progesterone are both at their lowest during this phase, which actually is beneficial from an exercise stand point. You can put on muscle more easily and have your best force generation all month long. You will also feel less pain and recover faster during this phase. What does this mean? The follicular phase is when you should be planning your cardio, HIIT, and strength based workouts. If you’ve got a competition, time trial or max out day planned, this would be ideal timing.

OVULATION

Ovulation is a bit of a mixed bag. While the physiology of ovulation may allow some people to feel optimal energy, confidence and creativity around ovulation, others may feel the hormone changes in a way that hampers their exercise. This phase I recommend really tuning in to what your body is asking for. If you feel great then this is an amazing time to try a new activity you haven’t done before or challenge yourself in the gym. If you have cramping, breast tenderness or feel moody, then scale it back!

LUTEAL PHASE

The luteal phase is when many people will notice a dip in energy and motivation when it comes to their workout routine, especially as they approach the premenstrual phase (3-5 days before your expected period). The good news is that key performance metrics like your VO2 max and lactate threshold remain consistent throughout the menstrual cycle - so if you do have a key workout or competition planned that falls on your luteal phase, it doesn’t mean you CAN’T perform well. It also isn’t dangerous to exert yourself during your luteal phase - our physiology just makes it challenging to have our best performance. Studies have shown that reaction time, neuromuscular coordination and manual dexterity are all reduced during the luteal phase - no wonder you missed that shot in soccer! Blood sugar regulation, breathing rates and thermoregulation are also negatively impacted during this time which makes the same endurance exercise we did in our follicular phase feel more difficult. It’s harder to build muscle in this phase because the high amounts of estrogen and progesterone impair muscle protein synthesis. If you’re following a training program and can’t back off during this phase, you can mitigate some of these effects by really focusing on your hydration and consuming more carbohydrates. If you do have some flexibility in your training, this is a good time to scale back and focus on lower intensity, technique based work like yoga, Pilates or lower intensity strength training. 

Syncing your workouts with your cycle takes some practice but it is well worth it! Not only can it help you maximize your fitness gains, but I find it consistently improves enjoyment and consistency in any exercise routine!

References

Lebrun, C. M. “Effect of the Different Phases of the Menstrual Cycle and Oral Contraceptives on Athletic Performance.” Sports Medicine (Auckland, N.Z.) 16, no. 6 (December 1993): 400–430. https://doi.org/10.2165/00007256-199316060-00005.

McNulty, Kelly Lee, Kirsty Jayne Elliott-Sale, Eimear Dolan, Paul Alan Swinton, Paul Ansdell, Stuart Goodall, Kevin Thomas, and Kirsty Marie Hicks. “The Effects of Menstrual Cycle Phase on Exercise Performance in Eumenorrheic Women: A Systematic Review and Meta-Analysis.” Sports Medicine (Auckland, N.z.) 50, no. 10 (2020): 1813–27. https://doi.org/10.1007/s40279-020-01319-3

Stacey T. Sims. ROAR. Rodale, 2016.