Do Menstrual Cycle Hormones Impact Performance?

Most female athletes are aware that their menstrual cycle influences how they feel. Some days training flows easily. Other days, the exact same session can feel unexpectedly harder. Energy may fluctuate. Heat may feel less tolerable. Recovery may feel different.

These experiences raise an important question: do hormonal fluctuations actually affect performance, or do they simply change how training feels?

To answer that, we first need to understand what is happening physiologically across the menstrual cycle.

The Menstual Cycle

"Natural Menstrual Cycle"

In a natural menstrual cycle, the brain and ovaries communicate continuously. Signals from the brain stimulate the ovaries to produce the two primary female sex hormones: oestrogen and progesterone. The levels of these hormones rise and fall in a predictable pattern across the cycle.

A textbook cycle is often described as lasting 28 days, although in reality there is significant variation between individuals, particularly in athletes.

The cycle can be broadly divided into three phases:

The early follicular phase begins with menstruation and includes the first few days that follow. During this time, both oestrogen and progesterone are at their lowest levels.

As the cycle progresses toward ovulation, oestrogen rises steadily while progesterone remains low. Ovulation marks the release of an egg from the ovary. The timing of ovulation varies between individuals, but it often occurs around the midpoint of the cycle.

After ovulation, the luteal phase begins. During this phase, progesterone and oestrogen levels rise. Toward the end of the cycle, both hormones fall again, which triggers the next menstrual period.

Hormonal Contraceptives

Hormonal contraceptives change this natural hormonal pattern.

With combined hormonal contraception, such as the oral contraceptive pill, hormone levels remain relatively stable because hormones are supplied externally. During the placebo week, hormone levels drop briefly, which causes a withdrawal bleed.

With progesterone-only methods, such as the implant or Mirena, progesterone levels remain elevated due to the continuous release of exogenous hormone.

As a result, the hormonal fluctuations seen in a natural cycle are largely suppressed.

Do Oestrogen and Progesterone Affect Exercise Physiology?

Substrate Use

Oestrogen and progesterone influence several physiological systems that are relevant to exercise, particularly metabolism and temperature regulation.

Oestrogen has several protective and supportive effects within the body. It plays an important role in bone health and supports muscle repair.

During submaximal endurance exercise, when oestrogen levels are higher, the body tends to rely more on fat as a fuel source and less on carbohydrate. This is often described as a glycogen-sparing effect.

In practical terms, this means the body may conserve carbohydrate stores slightly more effectively.

Progesterone has somewhat opposing effects. It is associated with increased protein breakdown. During the luteal phase, when progesterone is elevated, protein requirements may be slightly higher.

Thermoregulation

Oestrogen and progesterone also influence how the body regulates temperature.

Oestrogen promotes earlier onset of sweating and thirst. This allows the body to begin cooling sooner during exercise.

Progesterone has the opposite effect. It increases resting core body temperature and slightly delays the onset of sweating..

Training Status Matters

Context is important. 

Many of the metabolic differences observed across the menstrual cycle are significantly reduced when athletes are trained and fuelled. 

Carbohydrate intake before and during exercise overrides most hormone-related differences in fuel use. And as exercise intensity increases, carbohydrate becomes the dominant fuel source regardless of hormonal status.

Similarly, trained athletes develop highly effective thermoregulatory systems. Regular training and heat acclimation improve sweating responses and reduce the impact of hormonal fluctuations.

In other words, training adaptations and fuelling strategies have a far greater influence on performance than hormonal phase alone.

Take Home

Female sex hormones do influence exercise physiology. These effects are real and measurable. But they are modest.

There is no strong evidence to suggest that hormonal fluctuations across the menstrual cycle meaningfully impair performance in most athletes.

Oestrogen and progesterone often exert opposing effects, and their influence is further reduced by appropriate training and fuelling.

This does not mean the menstrual cycle should be ignored.

Athletes should be encouraged to track their cycles and pay attention to consistent patterns in how they feel and perform. If reliable, repeatable trends emerge, training can be adjusted accordingly.

But hormone phase alone should not dictate training decisions. Understanding the menstrual cycle provides useful context, but it is only one piece of a much larger performance picture.

The fundamental principles of training and performance still apply. Athletes should fuel appropriately, ensure adequate protein intake, and train in a way that is specific to their event, goals, and individual physiology rather than hormone levels alone.

Reference

1. Oosthuyse T, Bosch AN. The effect of the menstrual cycle on exercise metabolism: implications for exercise performance in eumenorrhoeic women. Sports Med. 2010;40(3):207–27.
2. Hackney AC. Menstrual Cycle Hormonal Changes and Energy Substrate Metabolism in Exercising Women: A Perspective. International Journal of Environmental Research and Public Health. 2021
3. Wenner, M.M., Stachenfeld, N.S. (2017). Sex Hormones and Environmental Factors Affecting Exercise. In: Hackney, A. (eds) Sex Hormones, Exercise and Women. Springer, Cham.