Why High Intensity Efforts are Harder in the Luteal Phase - And How to Train Smarter

If you’ve ever felt like your high-intensity workouts are harder during certain times of the month, you’re not imagining it. The luteal phase of the menstrual cycle—the time between ovulation and your period—brings hormonal shifts that make it harder to access carbohydrates for fuel which are vital to perform intense, short efforts. For young female athletes and active women who still have regular cycles, this can impact training performance, particularly in sports that rely on explosive power, sprinting, or endurance.

But don’t worry! With the right strategies, you can still perform at your best. Let’s break down why this happens and how you can adjust your nutrition and training to stay strong throughout your cycle.

Why Is It Harder to Use Carbs for Energy in the Luteal Phase?

1. Hormones Shift Your Fuel Preference

After ovulation, progesterone rises, and oestrogen remains elevated. These hormones influence metabolism, encouraging the body to burn more fat for fuel instead of carbohydrates (Hackney, 2020). While fat oxidation is great for steady-state endurance exercise, it can be a challenge for activities that require quick energy bursts, like sprinting, lifting weights, or high-intensity interval training (HIIT).

2. Reduced Glycogen Storage & Utilisation

Oestrogen and progesterone together reduce the ability to store and access muscle glycogen (Oosthuyse & Bosch, 2010). This means that if you’re used to tapping into stored carbs for energy during workouts, you might feel like you’re running out of steam faster.

3. Slightly Lower Insulin Sensitivity

During the luteal phase, muscles become less responsive to insulin, meaning that glucose uptake into muscle cells is slightly slower (Campbell et al., 2001). This doesn’t mean you should avoid carbs, but it does suggest that pre-exercise carbohydrate intake becomes even more important to ensure you have accessible energy.

4. Increased Energy Expenditure

Your resting metabolic rate (RMR) increases slightly during the luteal phase—by about 2-10% (Davidsen et al., 2007). While this might not seem like much, it can contribute to higher calorie and carbohydrate demands, especially if you’re training intensely.

How to Support High-Intensity Exercise in the Luteal Phase

Understanding these metabolic changes means you can make small but powerful adjustments to your nutrition and training to maintain performance.

1. Prioritise Pre-Exercise Carbohydrates

Since glycogen availability is lower, fuelling before workouts becomes crucial. Some great pre-exercise snack options include:

• A banana with honey

• A small smoothie with fruit and yogurt

• A slice of whole-grain toast with jam

• A handful of dried fruit and a protein source

These options provide fast-digesting carbs that can give your muscles the quick energy they need.

2. Time Your Carbohydrate Intake Strategically

Since insulin sensitivity is lower, try consuming carbohydrates 1-2 hours before training rather than immediately before. Post-workout, pairing carbs with protein (like Greek yogurt with berries or eggs with toast) helps replenish glycogen stores efficiently.

3. Adjust Workout Intensity When Needed

While you can still train hard in the luteal phase, some women notice their explosiveness or endurance drops slightly. If this happens:

• Prioritise strength training with slightly longer rest periods

• Use moderate weights with slightly lower rep ranges

• Incorporate steady-state cardio rather than relying only on HIIT

That said, every athlete is different—if you feel good, there’s no need to hold back!

4. Ensure You’re Getting Enough Calories

Since metabolic rate is slightly higher, under-fuelling can make fatigue worse. Make sure you’re eating enough throughout the day, especially if you’re training multiple times a week.

5. Consider Electrolyte Balance

Progesterone influences fluid balance, and some women experience increased sodium loss in the luteal phase. Adding a pinch of salt to meals or using electrolyte drinks can help maintain hydration levels, especially for endurance athletes.

Final Thoughts

Your menstrual cycle isn’t a barrier to high performance—it’s a tool you can work with. Understanding how hormones shift fuel availability can help you adjust your nutrition and training to stay strong and energised all month long.

By timing your carbs strategically, ensuring enough calorie intake, and adjusting training when needed, you can continue performing at your best, even during the luteal phase.

References

• Campbell, S. E., Angus, D. J., & Febbraio, M. A. (2001). Glucose kinetics and exercise performance during phases of the menstrual cycle. Journal of Applied Physiology, 90(1), 385-390.

• Davidsen, L., Vistisen, B., & Astrup, A. (2007). Impact of the menstrual cycle on determinants of energy balance. Human Reproduction, 22(9), 2254-2263.

• Hackney, A. C. (2020). The female athlete: Effect of menstrual status on maximal oxygen uptake. International Journal of Sports Medicine, 41(4), 256-262.

• Oosthuyse, T., & Bosch, A. N. (2010). The effect of the menstrual cycle on exercise metabolism: Implications for exercise performance in eumenorrheic women. Sports Medicine, 40(3), 207-227.