How to biohack your period for triathlon performance

In this month’s women’s training column, we learn how to biohack our periods to optimise triathlon training and recovery

how to biohack your period for athletic performance

We debuted our women’s training column back in November 2020 with advice on how best to maximise performance throughout the month (issue 383).


This month, we go one step further in outlining the best nutrition strategies to pair with this training during specific points of the menstrual hormone cycle.

A powerful natural process 

One of the largest physiological differences between the sexes is the constant, predictable fluctuation of female hormones caused by the menstruation cycle. Historically, this has been linked to mood swings and food cravings, which are usually accompanied by rolled eyes and the excuse that ‘it’s just that time of the month’.

But what if periods aren’t something to be feared and blamed? What if we instead simply viewed periods as a byproduct of a powerful natural process that, with the right research, could be tapped into and used to increase energy, strengthen our bodies, and build us into the best athletes we can be?

If the hormonal changes women experience could actually be harnessed and optimised to release a higher level of athletic performance, could the menstrual cycle create a gateway into an exclusively female training aid?

It’s important to note that every woman’s hormone cycle is different. That’s in terms of duration, intensity, and regularity. Some women experience PCOS, endometriosis, fatigue, or fertility issues, while others have no period at all.

Here, we’re looking at how those with regular menstruation cycles can take a deeper dive into the nuts and bolts of their hormone cycle, considering what type of exercise is best to do at what cyclical stage, and how a targeted diet along each point could further help to optimise athletic performance.

Follow your hormones 

Credit: Unsplash / Annika Gordon
Credit: Unsplash / Annika Gordon

During the menstrual cycle, the hormones oestrogen and progesterone increase and decrease at different stages. Taking a closer look at the movements of hormones in the body could provide an insight into the best times to train and fuel our bodies with different nutrients.

The first three to seven days of the menstrual cycle start with the shedding of the uterine lining which results in a period, during this time levels of oestrogen and progesterone are at their lowest.

Produced in the ovaries, adrenal glands and fat tissues, oestrogen is a hormone that helps to maintain and develop the reproductive system and develop some organs such as the breasts.

Aside from the menstrual cycle, levels of oestrogen in the body can also be affected by various factors such as diet, weight, age, and exercise. Women typically have higher levels of this hormone than men.

Oestrogen levels start to increase at the start of the menstrual cycle and peak at the point of ovulation at around day 14, at this time progesterone levels are low. This first half of the menstrual cycle is called the follicular phase.

Progesterone is another hormone that’s in flux during the menstrual cycle. It sends signals to the uterus to start preparing the body for pregnancy. This is when the womb lining becomes thicker and prepares for an egg.

After ovulation, we enter the second stage of the hormone cycle which sees an increase in progesterone and a decrease in oestrogen. This is the luteal phase and approximately occurs during days 15 to 28.

Towards the end of this phase, both oestrogen and progesterone will begin to fall, once again existing at their lowest at the start of the period.

Time to hit the gym 

Credit: Unsplash / Bruce Mars
Credit: Unsplash / Bruce Mars

As oestrogen rises in the body during the follicular phase of menstruation, the body should have a higher pain threshold and be more adaptable to intense training such as hard efforts on the track and seeing strength gains in the gym (study 2).

Of course, this won’t be the case for everyone as some women will find PMS (premenstrual syndrome) pain inhibits training, so it’s important to find what works for you. For those that can train though, now is when the body is most primed to build muscle and will store the least fat.

You’re also more sensitive to insulin during the follicular phase, with the body finding carbohydrate the easiest food group to metabolise into fuel during this time. Taking a carb-rich snack before and after sessions in this two-week period will boost energy levels and help speed up recovery (study 2).

Since the body thrives on high-quality carbs at this stage, ensure you’re consuming plenty of wholegrains, potatoes, pasta and rice. The body’s capacity to replenish glycogen stores is also at its best during this period, so hydrating with a carbohydrate electrolyte drink during training should do wonders in helping you recover from a session (study 1).

If you tend to bleed heavily during menstruation, consider stocking up on iron-rich foods and vitamin C, which has been shown to aid iron absorption.

Studies found a 30mg increase in iron can improve aerobic performance in female endurance athletes (study 1). Iron-rich foods include dark leafy greens like spinach and kale, as well as oranges, strawberries, beans, lentils, and poultry.

Switch to healthy fats 

Credit: Unsplash / Jason Briscoe
Credit: Unsplash / Jason Briscoe

During the luteal phase of the hormone cycle (typically days 15 to 28), the body has a higher level of progesterone running through it and oestrogen levels begin to fall. It’s at this point that the body starts to metabolise energy more efficiently from fat sources as opposed to carbs (study 2).

At this point, energy levels are likely to feel lower, core body temperature is higher, and the heart is working harder for the same efforts. It could now be a good idea to back off the intensity and switch over to steady, low-impact, endurance training that will boost endorphin and serotonin levels.

The body now metabolises fat more efficiently than carbohydrates, so you’ll requires a higher amount of healthy fat to fuel and recover from endurance sessions during this phase of the cycle (study 2).

To remain energised, the best foods to consume during this time should include healthy fats (avocados, nuts, fatty fish like salmon, as well as meats like pork and beef), some proteins, and less starchy carbohydrates.

Healthy food sources:

Carbs: Pasta, potato, rice, wholemeal bread, fruits.
Protein: Meat, fish, milk, tofu, eggs, pulses.
Fat: Avocado, coconut oil, chia seeds, nuts, fish.
Calcium: Milk, yoghurt, cheese, kale, edamame.
Iron: Liver, beef, chicken, tuna, nuts, dried fruit, tofu, spinach.
Vit C: Oranges, strawberries, cherries, peppers.
Vit B12: Beef, chicken, eggs, shellfish, cheese, nutritional yeast.

Midway through the luteal phase, progesterone levels will peak and this has been linked to an increased rate of protein metabolism when at rest and when exercising, so it’s a good idea to increase protein consumption during this time to maintain muscle mass (study 2).

As a guide, a study of female triathletes showed an average protein requirement of 1.63g/kg/day. During the luteal phase, sweat rate is also increased and the body is less able to efficiently absorb sports electrolytes drinks.

To compensate, athletes should up their fluid intake during this time and prioritise optimising hydration strategies if racing (study 1). As energy expenditure is increased by 2.5-11% during the luteal phase, some women might experience increased overall hunger and cravings to salty and sweet food (study 2).

Be sure to listen to your body during these times and up your food consumption to help your body continue performing at its best.

Track your cycle

Credit: Unsplash / Daria Nepriakhina
Credit: Unsplash / Daria Nepriakhina

This all sounds great, but what if you don’t know which stage of your hormone cycle you’re in? That’s where period-tracking apps come in.

Apps like Wild AI or Jennis (see details below) provide a great platform where you can log your period each month and educate yourself on the stages of your cycle and the best way to fuel and move your body during these times.

Wild AI is a free app that uses the personal data you input to calculate your optimal training, nutrition and recovery strategies. By selecting your menstruation status, the app uses this data, along with PMS symptoms, sleep time, training sessions, and resting heart rate to educate you on what’s going on in your body. Upgrading for £3.75/month unlocks coaches and training and nutrition plans.


Jennis is a period tracking app created by world champion heptathlete, Jessica Ennis-Hill and physiologist Dr Emma Ross. The app (£9.99/ month) aligns your workouts to your menstrual cycle, offering personalised training plans with a variety of exercises, along with insights into hormones and mood to help you train smarter and feel stronger. The personalised workouts are also designed to help reduce PMS pain. 

Some fitness tracking apps have also cottoned onto the trend, with brands like Garmin having a cycle plotter section in their Garmin Active App. [Check out issue 383 to learn about the best types and intensities of training you should do to align with your menstruation cycle.]

Along with a balanced diet and targeted foods, it’s important to also ensure you’re consuming enough key vitamins and minerals for health and performance. Women in particular should ensure they’re consuming adequate quantities of iron, calcium, vitamin C and vitamin B12.

It might seem wacky to be so in sync with your period and hormones, but there’s no need to shy away from harnessing the natural strength and endurance opportunities that come with the female hormone cycle.

In a world still so dominated by male sporting performance, why not take an empowered decision to optimise our own natural athletic potential as women?


1. Impact of nutrition-based interventions on athletic performance during menstrual cycle phases: a review. Macy M. Helm, Graham R. McGinnis and Arpita Basu.

2. Sex differences and considerations for female specific nutritional strategies: a narrative review. Kealey J. Wohlgemuth, Luke R. Arieta, et al.


Top image credit: Jeremy Stewart for Unsplash