Cycle syncing your workouts has been a super hot topic recently. There are a lot of different takes on the approach, and a lot are taken to an extreme. 

Today we are going to look at where the science currently sits on cycle syncing your workouts. 

Hormone cycles

Men have a circadian rhythm - 24 hour hormone cycle. They produce testosterone overnight, wake up with all their testosterone at the highest level in the morning. 

Women - have a 28 day hormone cycle - the menstrual cycle. Women have large cyclic fluctuations in sex hormones throughout the month. There are notably different phases in this cycle. We have the follicular phase - first 5-7 days of this is our period - low estrogen and progesterone. The ovulatory phase - high estrogen, low progesterone. The luteal phase - estrogen drops and progesterone increases throughout this stage. 

Obviously - the MC’s primary function is to support reproduction, however research has highlighted that the changing concentrations of estrogen and progesterone across the MC also impact other systems in the body including cardiovascular, respiratory, metabolic and neuromuscular - which can of course all impact exercise performance. 

Science on MC and exercise

As expected, the studies and research are limited. I considered a meta analysis which looked at a large number of studies on the MC and its impacts on women's performance. Data is conflicting, and there appears to be no clear consensus on how performance is affected by the phases of the MC. 

Results indicate performance might be “trivially reduced” during the early follicular phase of the MC (compared to other phases). However emphasis needs to be placed on trivial - further the studies considered were of poor quality, and the variation between the different studies. 

The key takeaway from this meta-analysis is that a personalised approach needs to be taken based on each individual's response to exercise performance across the MC.

I think as women - we know that there are differing energy levels during our cycle - we don’t need a study to tell us that - but everyone is different - and I think it is important to be flexible in your thinking around cycling. 

Personalised approach - what does this look like?

We talk about listening to your body a lot, and it is a skill that needs to be practiced. 

The trend of cycle syncing if nothing else has increased the body literacy of a lot of women which is a great outcome. It is important for women to be empowered and educated - to understand that their body is not the same every single month - and that is OK. That if you are feeling a specific way on a certain day - that perhaps this may be because of your cycle (although worth noting it could also be many other factors - stress, poor sleep, eating out or alcohol etc.). 

Issues we can see with cycle syncing:

Self fulfilling prophecy - if you tell yourself you will feel low energy and should only do light exercise during your period - this may become your truth. This is where training yourself to actually listen to your body on any given day is so so important. I know personally the first day or two of my cycle I have a bit of cramping and pain and generally feel a bit off. I will avoid cardio on those days, but I am still happy to weight train most of the time. I can always adjust the weights as needed.

Cycle syncing and muscle

• One of our key focus areas at Alimba is building muscle. We want our community to build strong healthy bodies for life, and one of the most important factors in this is building muscle. To build muscle - we need consistent programming and 1-3 heavy sets a week per muscle group. Now - we understand that this is not achievable every single week - but it is something to aim for. 
• A lot of these programs suggest walking and doing yoga or light pilates for the week of our period and maybe even the 5 days before our period. These are great forms of movement, but not the best for muscle growth. If we are missing out on about a third of the month without strength training - we are potentially hindering our progress with muscle growth.
• Muscle building workouts don’t have to be incredibly stressful - choose short, effective workouts that focus on control and isolating muscle groups, use support. 

Beyond exercise:

• Diet - 
• BMR - calories burnt at rest vary significantly during the menstrual cycle - according to one study, BMR decreased at menstruation and fell to its lowest point approximately 1 wk before ovulation subsequently rising until the beginning of the next menstrual period.
• Some other numbers I have seen are that during the phase where you are building up your uterine lining, your metabolic rate comes up and your protein needs can increase by about 12%. You therefore need more calories to support this. 
• Seed cycling is another interesting one - one study showed it was effective in improving hormone disturbances in women with PCOS - taking different seeds during the different cycle phases - particularly helping with progesterone. 
• Work - meetings etc. If you are really good at knowing when you may struggle in your cycle - you could try as much as possible to avoid big work meetings during these periods. Obviously this is not always possible but is just something to keep in mind if you have a very consistent predictable cycle and if you have some control over big work events.

Resources:

• McNulty KL, Elliott-Sale KJ, Dolan E, Swinton PA, Ansdell P, Goodall S, Thomas K, Hicks KM. The Effects of Menstrual Cycle Phase on Exercise Performance in Eumenorrheic Women: A Systematic Review and Meta-Analysis. Sports Med. 2020 Oct;50(10):1813-1827. doi: 10.1007/s40279-020-01319-3. PMID: 32661839; PMCID: PMC7497427.
• Solomon SJ, Kurzer MS, Calloway DH. Menstrual cycle and basal metabolic rate in women. Am J Clin Nutr. 1982 Oct;36(4):611-6. doi: 10.1093/ajcn/36.4.611. PMID: 7124662.
• Rasheed N, Ahmed A, Nosheen F, Imran A, Islam F, Noreen R, Chauhan A, Shah MA, Amer Ali Y. Effectiveness of combined seeds (pumpkin, sunflower, sesame, flaxseed): As adjacent therapy to treat polycystic ovary syndrome in females. Food Sci Nutr. 2023 Mar 25;11(6):3385-3393. doi: 10.1002/fsn3.3328. PMID: 37324929; PMCID: PMC10261760.
• https://www.drstacysims.com/blog/Cutting%20Through%20the%20Confusion%20of%20Cycle-Sync%20Style%20Training