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How your menstrual cycle can impact your training and fitness

With quite a few of my people clients asking me, and writing programs specifically around this, I thought I need to cover some of the basics in this week’s blog. 

Have you ever wondered why some weeks you’re feeling super motivated in the gym, getting personal bests every training session, and completely smashing your fitness goals; while other weeks, all you want to do is crawl out of bed mid-afternoon with the sole purpose of ingesting the entire contents of your freezer’s pizza and ice-cream drawer, while binge-watching a series on Netflix?

Although this cliché is often trivialized as ‘just girl problems’, for some, the mental, metabolic and hormonal fluctuations that occur throughout the menstrual cycle can be quite debilitating. We are all too familiar with the impact of the menstrual cycle on everyday living, and now, emerging evidence suggests that dependent on the stage of the cycle, training and sporting performance can also be greatly affected.

The basics

A woman's menstrual cycle is made up of four phases phases; the menstrualfollicularovulation, and luteal phases, which is often broken down more broadly into just the follicular and luteal phases.

First comes the menstrual phase, when a woman gets her period and her levels of the hormones estrogen and progesterone drop. This typically lasts 3-7 days but can vary between individuals.

This also kicks off the follicular phase, which begins on day one of your period and continues until ovulation, a total of about 16 days. During this phase, the pituitary gland releases follicle stimulating hormone (FSH).

During the ovulation phase, luteinizing hormone (LH) is released in response to the follicular phase’s rising estrogen levels. Wondering if you’re ovulating? One sign is a slight rise in body temperature, which happens around day 14 of your cycle.

Finally, we enter the luteal phase. This is where we see a rise in progesterone and a slight bump in estrogen levels, followed by a drop in both hormones and the restart of the cycle (barring pregnancy). The luteal phase is when we experience those *lovely* PMS symptoms, like bloating, headache, weight changes, food cravings, and trouble sleeping. This phase lasts 11-17 days.

How we can work these phases into our exercise routines

For endurance workouts

In a study of sedentary women, pre-exercise heart rate was higher and peak heart rate lower during the luteal and menstrual phases, respectively.1 In this same study, VO2 max and other measures of endurance were significantly lower in the follicular and menstrual phases.1

Try to save your higher-intensity workouts until the luteal phase is over, as this is when your heart is working slightly harder than normal; you'll reach a higher heart rate more quickly, especially when training in warmer temperatures. If you exercise according to heart rate zones, expect higher heart rates to be more of a challenge to reach during your menstrual phase. You might also see decreased endurance here, so if you're training for (or racing) an endurance event, try to opt for shorter workouts during your menstrual phase.

For strength workouts

While fluctuations of steroid hormones occur during the menstrual cycle, they have not been found to have a significant impact on muscle fatigue and strength. Carry on as normal! Of course, though the science shows no significant impact on your ability to perform these sports at any phase in your cycle, only you know how your body is feeling. Consider taking a step back and opting for more recovery if you’re feeling the symptoms of PMS such as fatigue, irritability, and mood changes.

So, to keep it simple: 

  • During days 1-14: opt for full body strength and hypertrophy training combined with days of longer duration aerobic training 40-60 minutes at 120-130 BPM. 
  • Luteal phase days 14-28: Focus on metabolic conditioning. Intervals of weights/ erg movements like rowing watt bike etc. Add in some super low intensity stuff like walking for 40 minutes.
Guide for Female Hormones

Hydration and your cycle

Something that's not normally mentioned is Fluid status, this will change throughout your cycle and can have an impact on your ability to exercise, especially in the heat. During the mid-luteal phase, there is a marked decrease in time to exhaustion, which is believed to be a result of increased body temperature, so pay extra attention to your water intake those days.

Increases in fluid retention can be a secondary effect of estrogen and progesterone, peaking from ovulation through the first half of the luteal phase. This fluid redistributes throughout your body during the luteal phase, creating a drop in plasma volume, which can compromise the amount of oxygen delivered to the muscles. This drop reduces sweat rate, and since sweat helps the body cool down, it can also result in an increase in body temperature. Due to these changes, women should be more aware of their hydration and fluid intake during the mid-luteal phase, especially if in hot and humid environments.

Changes in macronutrient needs

The way our bodies metabolize macronutrients, particularly carbohydrates and protein, can change through our cycle.

Carbs

In a fasted state, women were found to perform better in the follicular phase than the luteal phase. Female athletes preparing for an endurance event in their luteal phase should make sure they're eating adequate carbs during the event to meet increased needs.

Protein

Protein catabolism, the breakdown of muscles and other protein stores for cellular processes, has also been shown to beak with progesterone levels in the luteal phase, increasing protein needs during this part of a woman's cycle. Consider upping your protein intake during your luteal phase, especially if in a bigger or higher intensity training cycle.

When and how to optimize training around your cycle

For women whose performance is based on muscle output or VO2max, extra time planning your competition schedule around your cycle probably isn’t necessary. But women who participate in endurance exercise should consider adapting your competition schedule around your cycles. The shifts in fluid, body temperature, and metabolism can make it more challenging for women to undertake big training efforts and ensure adequate recovery in the luteal phase.

Start by tracking your cycle! Doing so can help you understand when your body enters each phase, any resulting symptoms, and how to adjust accordingly. We recognize that every woman's cycle is different, and a multitude of factors can play a role including the use of oral contraceptives, eating disorders, and medical conditions such as polycystic ovary syndrome (PCOS) or uterine fibroids.

Food journaling can also be helpful to assess for adequate macronutrients and fueling, especially when needs are higher. Performing sweat tests during your cycle can also be a tool to note any significant changes in fluid requirements to ensure adequate hydration and replenishing between sessions.

The bottom line

If you enjoy exercising and what to optimise your workouts, ensure that you’re taking a closer look at your body changes throughout your cycle can be an incredibly helpful tool. When we understand what’s going on the inside,we can set ourselves up for success in reaching our health and fitness goals. 

#trainsmart

Menstrual Phases