The Facts on Cycle Syncing and Exercise –
You’ve probably heard it — don’t lift heavy this week, go easy during that phase, plan your training around your cycle… but what if your muscles didn’t get the memo?

New research shows that women can build muscle just as effectively after strength training no matter where they are in their menstrual cycle.
The 2024 muscle protein synthesis study was an original research trial measuring how muscle responds at the cellular level to resistance exercise in different menstrual cycle phases.
- It directly measured muscle protein synthesis and protein breakdown after strength training during peak estrogen vs peak progesterone in 12 healthy young women.
- It looked at muscle adaptation, not how you feel over the course of the menstrual cycle.
- They were tested in late follicular and mid-luteal phases. They wanted to compare the two strongest hormonal contrast as well as testi the hypothesis that: High estrogen = more anabolic and High progesterone = less anabolic, So they picked phases where hormones are clearly different and easier to verify biologically.
- Each phase included: 6 days of controlled resistance exercise, muscle biopsies, stable isotope tracing (gold-standard MPS method). Phases were confirmed using: cycle tracking, hormone blood tests & urinary ovulation tests. Methodologically, this is a very strong design compared to older menstrual-cycle research.
Key result:
- There was no difference in how much muscle protein was built or broken down between menstrual cycle phases — the muscle responded the same no matter the phase.
- Therefore, Hormone shifts throughout the cycle does not reduce muscle-building or increase muscle breakdown (but we will look at what DOES).
⚠️ BUT — here’s where social media hasn’t caught up.
This study does NOT mean:
❌ Women should train exactly like men
❌ The menstrual cycle is irrelevant
❌ Female-specific coaching is unnecessary.
It ONLY examined:
Muscle protein synthesis response to resistance training.
That is one narrow piece of physiology.
It did not assess:
- fatigue perception
- glycogen use / carb access
- recovery speed
- thermoregulation
- mood or CNS readiness
- injury risk
And other studies show those things can vary across the cycle. For example, glycogen use during intense exercise may differ between phases. Recovery may be harder in the luteal phase as inflammation is higher.
You’re not “losing gains” because of where you are on your cycle. But training with your cycle may be stealing them. How?
Well, life already dictates training and riding windows (kids, work, sleep, weather etc). Waiting for the “right week” could mean not training at all – if the weather is bad, your kids are sick or you get asked to work extra shifts. And this is the worst thing for your strength!
Strength training (during all phases of the menstrual cycle) supports:
- Climbing power on the bike
- Injury prevention by strengthening connective tissues, supporting joints, improving balance, coordination and posture
- Improves endurance + Fatigue resistance on long rides
- Better immune function in women and overall health.
- Heart health
- Hormonal Balance: Helps regulate insulin, cortisol, and estrogen
- bone density
- Metabolism & body composition
- Confidence & Mental Health: Releases endorphins, reduces stress/anxiety, and improves cognitive function and encourages Empowerment & resilience.
Strength training is essential for women and is beneficial for mountain biking, mumlife and everyday tasks- regardless of where you are in your cycle.
Cycle Awareness, Not Cycle Restrictions.
Cycle syncing is amazing, WHEN DONE RIGHT. Cycle syncing isn’t about avoiding certain types of training on certain weeks – it’s about reframing how to listen to your body.
It doesn’t mean we’re going back to training like”small men.” We train with science, not outdated assumptions.
Remember, this study looked at muscle adaptation, not how you feel.
FACT. Your Energy, motivation, cramps, sleep and stress still fluctuate due to your cycle. And by listening to these cues – You can adapt your training, recovery and nutrient needs to what your cycle is telling you.
For example, let’s say it’s your late follicular phase. You are feeling your best. You have heaps of energy and are feeling mentally strong. But your kids have a nasty colds and they have stay home from school for a few days. You skip training and riding for a few days until they recover. You miss your “window” to train hard and hit those technical features on the trails because during this time, you enter your luteal phase. Should you still train hard? or Should you focus on taking it easy because you’re no longer in the follicular phase?
The answer is no.
Cycle awareness means still training hard. But knowing, that it might hurt more if you’re in your luteal phase. It means going into your session with more food in your belly, and eating more in the hours post session. It means going to bed a little earlier and doing a little bit more self care to avoid burn out, injury, or getting run down. But you can still lift heavy, and ride hard. You just need a little more planning and recovery.
You don’t change your identity as an athlete — you adjust how you approach training based on what your body is telling you at that time.
It’s not strict “cycle syncing.”
It’s informed flexibility.
Example 2:
Let’s say there’s a hard ride planned on the weekend or you’ve planned hard interval sessions.
Cycle awareness looks like:
- Eating more carbs beforehand
- Bringing extra fuel on the ride
- Expecting it to feel harder
- Keeping the session, but adjusting expectations.
NOT:
– Cancelling training automatically
– Thinking you can’t perform or thinking you won’t build muscle afterwards.
It’s okay to:
- Lift heavy when you feel good
- Go lighter when you don’t.
- Training without guilt or worrying that you’re not going to “gain” if you train in the “wrong?” Phase.
Tracking patterns over months:
- noticing when sleep dips
- when motivation drops
- when strength feels easiest
- when hunger increasesand making the necessary adjustments – WITH OUT THE GUILT!
What cycle awareness is NOT
- Not avoiding certain weeks.
- Not fear-based training.
- Not believing you only make gains in one phase.
- Not rigid rules
- Not “all or nothing’ thinking.
It’s simply:
Listening + adjusting + staying consistent. You don’t need a perfect phase. You need consistency, confidence, and a plan that works for your life.
Why Training Feels Different at Different Times.
The hormones that dictate our menstrual cycle affect every system in the body, with symptoms that extend far beyond just the reproductive system. No doubt you’ve experienced this – things like appetite changes (hello cravings!)motivation, mood, energy and body temperature are regular ups and downs for menstruating women.
The menstrual cycle influences:
- How much energy we have and how much we can utilise,
- Cardiovascular performance
- Muscle strength
- Vulnerability to injury
- Immunity
- Metabolism
- Appetite
- Core temperature
- Pain tolerance
- Emotional disposition
- Digestion
- Dietary needs
- Cognition and memory.
And even though scientific evidence doesn’t consistently show big differences in actual athletic performance, it does show that women feel different at different phases across the menstrual cycle. These things are not in your head! These are real physiological changes that happen throughout the menstrual cycle, and impact even the most experienced elite athletes at times.
We also know we’re different from men. Different physiology. So we need a different strategy.
The saying “no rest days” or “beast mode” IS JUST NOT compatible with women’s physiology. We NEED more sleep than men, different recovery strategies, and more down time for hormonal balance. And it’s harder for us to build muscle compared to men – so we still need to train differently, especially as we age.
Body Literacy: Learning to Read the Signs
The good news is that the more we understand our own cycle and the impact it has on our mood, energy, appetite, thirst etc – the better we get at listening to our body and adapting our training (if we need to). This is called body literacy. It’s literally the ability to read your body’s signs and symptoms as if it were talking to you. And, no matter what sort of riding you’re into and what level you are, all women can benefit from understanding their cycle.
And it’s not just physical or performance based. Those benefits extend to mental, metabolic, immune and emotional health too.
It’s super important for understanding what’s going on in your body at a deeper level too – things like ovulation, fertility, period problems, inflammation, perimenopause, avoiding burnout and even preserving your emotional health too.
To do this properly – you’ll need to track your cycle + symptoms to see your pattern so you can start listening.
The average cycle is 21-35 days. The menstrual cycle is made up of four unique phases.
- Menstruation (shedding of the uterine lining) Week 1 days 1-7,
- The follicular phase Weeks 1-2, days 1 – 14 (follicle development and estrogen rise),
- Ovulation (egg release), 1-2 days anywhere from day 7-14
- The Luteal phase, Weeks 3-4 days 8 to 32 (preparation for potential pregnancy, building of the uterine lining).
As already mentioned – each phase influences our energy, strength, vulnerability to injury, immunity, cardiovascular system, metabolism, appetite, core temperature, pain tolerance, our mental and cognitive health, and also our digestion in unique ways. For example, in the follicular phase inflammation is lower and you recover better. YOu also access energy better and overall you adapt better to training. You’re more resilient and may even feel stronger and perform better.
Once you sit up and take notice of your cycle, you will start to see a pattern, and realise, it’s not that subtle at all. In fact it can be very very loud!

Listening to your cycle. (aka the real cycle syncing)
- Lifting weights increases muscle building in women, all month long. However, You may feel stronger in the follicular phase because you have more energy available to you, and your mental resilience is higher here.
- This muscle-building response is the same no matter where someone is in their menstrual cycle.
- Being in the follicular phase (higher estrogen) or the luteal phase (higher progesterone) does not change how much muscle protein is built after resistance exercise.
- The menstrual cycle phase also does not affect muscle protein breakdown after exercise. What does affect muscle protein breakdown is what you do after exercise to recover.
Bottom line:
Your menstrual cycle phase does not change how your muscles respond to resistance training in terms of muscle building. However, your cycle phase does directly impact energy, strength, and endurance for exercise due to fluctuating hormone levels.
Energy is generally highest during the mid-follicular phase and around ovulation due to low progesterone, while the luteal phase (pre-period) often brings lower energy, higher fatigue, and reduced motivation.
Stick around for part 2 – where I am going to share more insights on how to understand your cycle, how to track your cycle, understanding contraception’s impact on hormones and performance, & how to know if you’re in perimenopause.
In the meantime, if you’re looking for coaching and more guidance on hormones, wellness and performance, then you’re in the right place. I meet women where they are: You don’t have to be an elite athlete to coach with me.
I’ve found in MTB:
- some women want performance
- some women just want fun
- some want community
- and some want guidance.
So whatever your goals are and no matter where you’re starting from, I’m here for you. MTB mamas is community-driven, evidence-based and human first. Not rigid. Book a session in now.
You’ve got this,
Ali x x
reference: https://pubmed.ncbi.nlm.nih.gov/39630025/





