What is cycle-synced fitness and do we need it?
Article #2 of Raising our voices, even louder! A women's health long-read content series
Welcome to 'Raising our voices, even louder' – a content series that takes a deep dive into core women's health topics.
Last month, I covered brain health, and I move now into fitness.
As many of these articles will begin, female sports science is an area that is chronically under-researched. As a result, we have limited female-centered data, meaning that much of the fitness advice, equipment, protocols, and kit have been created with the male body in mind.
This data gap leads to an increased risk of injury and suboptimal performance.
At the heart of these differences, of course, is the menstrual cycle. Anyone living with the monthly ups and downs will attest to the variances in their strength and agility. Some days, lifting the heavier weight or reaching that PB simply feels easier.
Thankfully, innovators and scientists are working to level the playing field and give women the insights they need.
We now have a new category emerging – cycle-synced fitness – which looks to examine these monthly changes and optimise our fitness performance around them.
And #cyclesyncing is not just a TikTok craze. Professional sports bodies like the French Institute of Sport and the US Women's Football (soccer) team have explored cycle tracking within their training.
But how far should we go with this cycle-synced approach? Do we have all the information we need yet to integrate it into our routine? Are there any downsides?
I've teamed up with Nancy Best, women's fitness expert and founder of Ladies Who Crunch to explore this topic in more detail.
Sex and sport
We know that in sports science and medicine, only six per cent of research in 2020 was conducted exclusively on females. This is not helped by an underrepresentation academically too - female first and last authorship on scientific publications is less than 25%.1
But, what are the differences between the sexes when it comes to sport?
“There's a famous quote from Dr Stacy Sims, the renounced exercise physiologist and nutrition scientist; 'Women are not small men', which sums this topic up succinctly. For decades, most of the research into sports performance has focused on male data and then extrapolated the conclusions for women.
From a nutritional perspective, the WHO's generic recommendation on daily caloric intake (2,500 for men and 2,000 for women), gives no nuance to the menstrual cycle and its impact on your basal metabolic rate. During women's luteal phase, the basal metabolic rate (the number of calories you burn as your body performs basic life-sustaining function) increases by an average of 100-300 calories per day. In other words, women's bodies need more fuel.
Furthermore, when women's oestrogen levels are higher during their menstrual cycle, studies have shown that carbohydrate oxidation can be reduced by between 5-16%. That means your body is not utilising carbohydrates for fuel as much as 'normal' - so if you're doing lots of high intensity exercise and just generally rushing around stressed, you're going to need extra carbs!
Most women don't adapt their lifestyle in any way to accommodate for any of this, which can really affect sports performance.
Physically, women are more at risk of developing osteoporosis than men because of hormonal changes during menopause directly affect bone density. After the age of 35, women's muscle mass decreases by between 3-8%, per decade. Without the same testosterone levels as men, strength training is essential for maintaining muscular-skeletal health. One study found that post-menopausal women who consistently lift weights recorded improved sleep and reduced menstrual symptoms.2”
What I'm hearing is that we all need to hit the weight room! What about injuries? Are there differences there, Nancy?
“This is a really 'hot topic' at the moment, with the spotlight on women's football. According to research, female athletes are two to eight times more likely to experience an ACL tear than males. Oestrogen levels also cause greater laxity in tendons and ligaments, which can make women more prone to injury across the board.
There's a careful balance to strike between educating women about the potential risks, without putting them off sport entirely! It comes back to the earlier point about the importance of building muscle mass, to help absorb the impact of exercise and protect your joints.”
All this points to cycle tracking being a useful companion to our exercise regimen. If we know where we are in the menstrual cycle, we can see trends and patterns in our performance.
Cycle-synced fitness
Ahead of the 2022 Women's Euros, England Lioness Nikita Parris revealed how cycle tracking was an important pillar of the team's training plan. But what is it?
“Cycle-synced fitness is a method of tailoring your training approach to the hormonal changes around menstruation. A useful analogy is the seasons:
- winter is your bleed
- spring is your follicular phase
- summer is your ovulation
- autumn is your luteal phase
Mapping your training to your menstrual cycle is predominantly tied to the changing oestrogen and progesterone levels. Oestrogen increases the anabolic response to exercise, meaning when levels are high, it's the ideal time to test for strength PBs. In contrast, as progesterone dominates in the luteal phase, inflammatory markers are up, so prioritising lower impact, restorative moment can help ease symptoms.”
I'm all for listening to our bodies, but I know this approach has its critics that claim it limits women. After all, we are more than just our hormones.
Plus, considering how little we know about our hormonal changes and menstrual cycles, can we make big claims around performance yet?
“Most women don't have a "standard" 28-day cycle and some women have a longer luteal phase than others.
My biggest concern with cycled-synced fitness is that we move into generic advice, which stops women truly listening to their own bodies and its signals.
This is why I advise my clients to keep their own track of symptoms, without following the prompts of an app. I created a simple document to help them know what to look out for, under three headings – 1) vaginal, 2) face and body, 3) mood and mind.”
The truth is the clinical evidence is still light on the ground here but there is plenty of anecdotal evidence to suggest its merits. Thankfully, we have innovators in this space, like Wild Ai and Jennis, who are working to give us the big data sets we need to understand female sports science better.
Peak performance
While we wait for the research gap to be closed, there are things we can all do at different life stages to optimise our health.
“Aside from reducing the risk of osteoporosis as mentioned above, promoting pelvic health is vital for women of all ages.
Pelvic floor strength is still shrouded in taboo and misunderstanding.
The statistics are shocking; one in ten women will need at least one pelvic floor surgical procedure in their lifetime, whilst one in three women experience urinary incontinence in the first year post-partum. Many women who have had a C-section don't know that they still need to do pelvic floor rehab after birth.
We need to empower women to learn how to strengthen the pelvic floor properly, not just for pregnancy, but from the moment we hit puberty. The NHS has announced that specialist pelvic health clinics will be rolled out across the UK. Great progress, but it's far too slow.”
A note on those pelvic health clinics: funding isn't where we want it to be and doesn't seem to go where we need it. Add in an upcoming General Election in the UK, and those of us here could be waiting a while for these provisions.
In the meantime, brands like MUTU System and Elvie have great tools to support your pelvic health at home.
Will weight remain heavy on our minds?
The good news is that some of the research we need is happening. We now have organisations and initiatives like the UK's Centre of Excellence for Women in Sport, Norway's The FENDURA research project and Stanford University runs the Female Athlete Science and Translational Research (FASTR) Program.
Plus, companies like Well HQ are embedding female sports science into professional coaching and physical education in schools.
I get very excited to think about the future of female fitness, where we've learnt to optimise and protect our bodies. We'll have sports bras that keep our breasts healthy and nutritional guidance that matches our genuine needs.
But can we shake off the age-old connection between weight and fitness? Will our newfound knowledge help us feel more comfortable in our own gorgeous skin?
“Despite the huge progress made in the fitness industry to focus on the holistic benefits of exercise, diet culture is still very prevalent. For so many women, exercise is a form of punishment, to 'burn off' a meal or 'torch cellulite'.
I'm hopeful that as the government tackles the mental health crisis in the UK, we'll see more resources available to help women connect to exercise beyond aesthetics.
At the moment, the Mood Glossary (a practical guide I created to help members of Ladies Who Crunch reflect on how they are feeling emotionally, to find the most appropriate class) feels very niche, but I hope that'll change.”
If this has got you thinking you need to up your fitness game, here's what Nancy says are the three things to focus on now:
1) Lift weights twice a week, at a minimum - the British Journal of Sports Medicine published findings that showed that muscle strengthening was associated with a 10% to 17% lower risk of death.
2) Focus on getting enough protein - according to one survey (referenced here), 50% of women aged between 18-50 don't know if they get enough protein. In my experience, when I explain to clients that the RDA for maintaining bone density and muscle mass is currently 0.8 grams of protein per kilo of body weight per day, they are shocked. Reaching that target requires planning and a broad understanding of the totals one can get from wholefood sources like meat, fish, lentils and pulses.
3) Discipline is more powerful than motivation - one of the biggest mistakes that I see in fitness is when women rely on 'feeling motivated', to either get started or keep a routine afloat. Motivation fluctuates. Discipline is about identity – what habits would you change, if you were to channel a certain identity? Ask yourself - what actions would you take, to be that person?
Anyone else Googling 'how to eat more protein'?
Ladies Who Crunch is an online fitness membership that delivers a structured training programme & a supportive, empowering female-only community.
Combining a monthly calendar of live workouts and inspirational content covering everything from nutrition guides to mental wellbeing hacks, alongside access to a growing library of over 400 unique on-demand workouts. Learn more here.
Sources
Nash Anderson, Diana Gai Robinson, Evert Verhagen, Kristina Fagher, Pascal Edouard, et all. (2023). 'Under-representation of women is alive and well in sport and exercise medicine: what it looks like and what we can do about it'. BMJ Open Sport Exerc Med. Available at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10186450/ (Accessed June 2024)
E. Berin, M. Hammar, H. Lindblom, L. Lindh-Åstrand,, A.-C. Spetz Holm. (2022). 'Effects of resistance training on quality of life in postmenopausal women with vasomotor symptoms'. Climacteric . Available at https://www.tandfonline.com/doi/full/10.1080/13697137.2021.1941849 (Accessed June 2024)