Dr Nick Fuller
Leading Obesity Expert at the University of Sydney and founder of Interval Weight Loss.
It’s normal to feel energetic and motivated for a workout some days, while on others, you might struggle to get moving.
For women, there’s a clear physiological reason for this. While men’s hormone levels shift slowly over their lifetime, women experience daily fluctuations in sex hormones.
Researchers are still exploring the full effects of the menstrual cycle on exercise. However, it’s clear that hormonal changes throughout the cycle can influence metabolism, energy, and recovery, especially for women engaged in endurance training.
Knowing how hormone levels rise and fall during the cycle can help women tailor their workouts, improving performance and supporting weight loss or fitness goals.
The typical menstrual cycle lasts around 28 days and can be divided into two main stages: the follicular phase and the luteal phase.
The follicular phase runs from day 1 to 14, starting on the first day of menstruation. During this period, oestrogen levels steadily rise while progesterone remains relatively constant. Metabolically, women are more similar to men during this phase, which means workouts feel easier and recovery tends to be faster. This effect becomes even more noticeable in the latter part of the follicular phase.
Around day 12, oestrogen and luteinising hormone spike, triggering ovulation. Energy levels and strength often peak at this time, making it ideal for pushing yourself harder in training.
For women aiming to build fitness or lose weight, the end of the follicular phase is the best time to introduce new exercises or increase workout intensity.
The luteal phase marks the second half of the menstrual cycle.
During this stage, progesterone levels reach their peak. This can increase your resting heart rate, reduce aerobic performance, and make it harder to tolerate heat. Workouts may feel more challenging, and fatigue can set in sooner.
Metabolically, the body relies more on fat as fuel because high oestrogen and progesterone levels suppress gluconeogenesis, the process of producing sugar from protein and fat. While this might sound promising for fat burning, it makes glucose less accessible, so exercise can feel tougher than usual.
For this phase, it’s best to prioritise lower-intensity cardio, strength training, and active recovery activities like walking, yoga, or stretching. Progesterone also contributes to muscle breakdown, slowing recovery and limiting strength gains.
Hormonal shifts during the luteal phase can cause fluid retention, bloating, and premenstrual symptoms like headaches or fatigue, making exercise feel even harder. Your metabolism also rises by around 5–10% from its lowest point before ovulation, and appetite often increases. Low-intensity workouts paired with well-timed nutrition can help manage this.
Eating carbohydrates and protein within a few hours of exercise can boost energy and support recovery. Try snacks like fruit with nut butter, wholegrain bread with fruit spread, or yoghurt. Include foods naturally rich in healthy fats and sugars, such as avocado, nuts, seeds, and fruit, which satisfy cravings in a natural way.
Your energy and cravings might shift across your cycle, but that doesn’t mean you’re off track. Discover why occasional bloating isn’t real weight gain in: How To Know If You're Bloated Or Gaining Weight.
When menstruation begins, hormone levels reset, and many women notice a boost in energy, mood, and motivation. Using this phase strategically can help you optimise workouts and nutrition, making it easier to achieve your fitness and health goals without pushing your body too hard.
Start tracking your cycle by noting the first and last days of your period and counting the days between two consecutive cycles to determine your average cycle length. Digital apps can simplify this process, sending reminders and highlighting different phases. This allows you to plan exercise intensity, rest days, and nutrition in line with your body’s natural rhythms.
Over time, tracking your cycle can help you identify patterns in energy, cravings, and recovery, enabling smarter training decisions and better overall results.
Being aware of the hormonal changes throughout your menstrual cycle allows women to plan workouts and nutrition more effectively. Adjusting intensity during the luteal phase and taking advantage of higher energy during the follicular phase help optimise performance, recovery, and weight management.
Tracking your cycle provides insight into when to push harder and when to prioritise lower-intensity activity and recovery. Coupled with balanced nutrition, this approach supports consistent progress toward health, fitness, and weight-loss goals.
Ultimately, listening to your body and aligning exercise and eating patterns with your menstrual cycle can make your fitness journey more effective and sustainable.
If your fitness routine feels harder to stick to at different points in your cycle, you’re definitely not the only one. Weight loss often hits plateaus for many people. Learn strategies to push past those blocks in Weight Loss Plateau Solutions That Work.
Dr Nick Fuller is the founder of Interval Weight Loss and is a leading obesity expert at the University of Sydney with a Ph.D. in Obesity Treatment. Dr Fuller is also the author of three best-selling books and his work been published in top ranked journals in the medical field, including JAMA, Lancet and American Journal of Clinical Nutrition.