Simple 5 Point Guide To Smarter Exercise During The Monthly Cycle
Written by Dan Raynham, The Fitness Scientists
Dan Raynham is a leading innovator of biohacking, peak fitness, and age reversal. He is the founder of The Fitness Scientists, the world's only measurable wellbeing system. His latest passion project, "The Biohacking Handbook," is a TV show that aims to democratize peak health, combining his background in science and the arts.
Traditional fitness advice for women is broken. Here is one way we can start to fix it. Guys, imagine being told to 'just train' when your body's biochemical landscape is shifting like the tides, estrogen surges, progesterone dips, and serotonin takes a nosedive. For millions of women, this isn't a hypothetical scenario, it's their monthly reality. Yet, the intersection of exercise and the menstrual cycle remains a woefully understudied and overlooked topic. As a late-blooming ally, I'm ashamed it took me this long to grasp the obvious, which should be basic knowledge, taught in schools worldwide. So, I'm breaking my silence with a simple, 5-point guide, not just for women to reclaim their fitness, but for men to become the allies they should always have been. Simple and factual with science citations as usual, which is the only way in my book! This isn't about periodization training, that's still up in the air, evidence-wise. This is a gentle guide, a starting point. Remember: no citations and it might be an opinion piece! [1]
The original textbooks were written by men
Let's face it, guys, if you are biologically born a bloke, you just train. But if you have periods, your body has a lot more going on biochemically, and it can be a real challenge. The thing is, men wrote most of the medical textbooks and fitness traditions years ago, and let's just say some of it's not exactly helpful for this cause.
Enough's enough with the fitness fads and influencers peddling unproven ideas about training and the menstrual cycle. Let's cut through this potentially harmful content and focus on what actually works. Simple, proven, straightforward, and easy to remember, that's the key to getting results. [3] [4] [5] [6]
Brief primer on the biology of periods
The menstrual cycle is a complex interplay of hormones, primarily estrogen and progesterone. In the follicular phase (days 1-14), estrogen levels rise, promoting follicular growth and increasing serotonin. At ovulation (around day 14), estrogen peaks and progesterone starts to rise. In the luteal phase (days 15-28), progesterone dominates, affecting thermoregulation, sleep, and mood, while estrogen declines. This shift can lead to symptoms like bloating, fatigue, and mood changes. Estrogen and progesterone levels drop during menstruation, triggering uterine shedding. [7]
5 key points for training during the menstrual cycle
First half of your cycle: Estrogen's dominant, so you're good to go for better workouts.
Mid-cycle, pre-ovulation: Estrogen surge = muscle-building heaven! Train hard, you've got the energy.
At ovulation: Progesterone's in charge, serotonin takes a hit, and energy levels plummet. It's tough, but try to adapt.
Second half: Energy's generally lower, but progesterone's got flexibility on your side.
Period: Estrogen and progesterone drop, and energy's at rock bottom. Listen to your body. [7] [12]
Most studies focus on athletes, where performance often isn't affected, but this guide is for everyday people, acknowledging the potential impact on your training and how tough it can be. More research may unlock useful tools for both everyday fitness enthusiasts and elite athletes.
What are these hormones?
Sometimes, breaking down complexities to biology, evolution, or maths can help me navigate the world with more calmness. Here's a breakdown of the biochemicals at play:
Estrogen (a steroid hormone produced by the ovaries) regulates female reproductive health and mood. Steroid hormones are lipid-soluble, derived from cholesterol, and can diffuse through cell membranes, directly influencing gene expression.
Progesterone (a steroid hormone produced by the ovaries) prepares the uterus for pregnancy and has calming effects on the nervous system.
Serotonin (neurotransmitter, produced by the brain and gut) regulates mood, appetite, and sleep. Neurotransmitters are chemical messengers that transmit signals between neurons or to muscles/glands, facilitating rapid communication. Unlike steroid hormones, they're typically water-soluble and bind to receptors on cell surfaces, triggering responses.
These biochemicals interact throughout the menstrual cycle, influencing energy, mood, and physiology, often impacting daily life. [7]
Everyone is different
Everyone's unique, and factors like fitness level, lifestyle, and individual physiology play a big role. Generally, the fitter you are, the easier it might be to adapt to your cycle's ebbs and flows. The key is tuning into your body's signals and working with your cycle, not against it. If you're feeling drained and high-impact exercise feels like a chore, don't force it. Try low-intensity activities instead. Or, simply take a rest day, it's often the best thing you can do. On the flip side, harness the energy and strength boosts, like the pre-ovulation muscle-building window, to push yourself and make progress. Experiment, find what works for you. Modern research has shown that the length and severity of menstruation is way more varied than previously known. [8] [9] [10]
Time to acknowledge and make a difference
Learning these basics and applying them can make a big difference. Let's be honest and upfront about this, so we can all train more effectively, together. And if some guy in the gym or trainer gives you inconsiderate grief, just tell 'em, "I'm high on progesterone and low on serotonin. You might want to get on board with the science bro!” [11]
Science to empower
Empowerment comes from understanding knowing how your body works and leveraging that knowledge to take control of your fitness and wellbeing. This guide isn't a fitness plan, nutrition bible, or psychology manual, it's a primer on the basics that should be taught in schools. By understanding the fundamentals of your menstrual cycle and how it impacts your energy, mood, and physiology, you can start to make informed choices about your body. It's about stripping away the mystery and misinformation, and getting back to basics. From there, you can optimize workouts, anticipate challenges, and develop a kinder, more compassionate relationship with your body. That's not just smarter exercise, that's taking charge of your health. Remember, if there are no citations, it might just be an opinion piece!
In summary
First half of the cycle – Full on.
Midway – Train hard.
Ovulation – Sudden energy drop, it is getting hard to train now.
Second half – Energy is lower, try your best or mix it up.
Period – Energy rock bottom listen to body do what you can or rest.
I have received no sponsorship or payment for this article. There are no conflicts of interest.
Let's connect
Got questions or need more references about training with the menstrual cycle, biohacking or just wanting to boost your fitness? I'm here to help - whether it's for you or your organisation. At The Fitness Scientists, we cut through the noise with science-backed methods for a clear path to better health.
Phone: +44 7957 297872
Photos © 2026 Dan Raynham
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Dan Raynham, The Fitness Scientists
Dan Raynham is a science-driven biohacker who believes that everyone should have access to optimal health. As a child, he suffered poor health, and didn't start exercising until his 30s. Now, at 51, he is an elite athlete who outperforms teens to 20s and professional athletes. Over the course of 20 years, he has honed a ground-breaking system that activates the body into peak fitness and age reversal. It works at a cell and molecular level in an incredible display of biochemistry. An ardent supporter of science-led, compassionate health and mythbusting, his company, The Fitness Scientists, offers the first and only data-driven wellbeing plan in the world.
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