Strength Training vs. The Menstrual Cycle: What Do We Know?

By Angie Hurley, CSCS, Cat(c)

It’s no secret. During a woman’s reproductive years, her hormones can sometimes make her feel like a completely different person physically, mentally and emotionally, from week to week. Despite this fact, the way in which women’s hormones affect strength training, and vice versa, has not been very closely examined. 

Some of the reasons why most strength research uses male subjects include: 

  • Fewer females in the weight room leading to fewer female participants. Until the last decade or two, the weight room was dominated by men.
  • Fewer female researchers in exercise science academia
  • Female hormonal fluctuations have greater variability compared to than that of males making research more complex and more expensive

The Main Players AKA Your Hormones

To maximize training, key hormones to consider during the menstrual cycle include growth hormone, estrogen, testosterone, progesterone, and relaxin.

With a little planning, you can work with, not against, your body to get the best training out of yourself. Greater understanding of your hormones can help you ensure that you avoid being sidelined! Let’s learn a little more about the MVPs:

Growth Hormone:

  • Stimulates muscle building and repair
  • Releases stored fat
  • Increases insulin sensitivity
  • Peaks during sleep
  • Increases with strength training.

Estrogen:

  • The female sex hormone. (Although men have estrogen too!)
  • Regulates bone growth, bone remodeling, and the menstrual cycle.
  • Regulated with strength training.

Testosterone:

  • The male sex hormone (10-20x lower in women than in men)
  • Increases muscle mass and strength
  • Burns “non-functional” body fat
  • Stimulates sex drive
  • Stimulated by long-term strength training.

Progesterone:

  • Regulates menstruation
  • Prepares body for pregnancy
  • Prepares uterine lining for egg implantation
  • Strength training in high volumes at high intensities decreases progesterone and can distort the menstrual cycle
  • Strength training in short duration and high intensity or moderate volume and moderate intensity regulates progesterone production. 

The Plot AKA Your Uterus Thins, then Thickens

Despite the cycle being illustrated in most course textbooks as a neat little Day 1 through 35 schedule, we know that some women experience strict regularity, while others experience extreme variability:

  • One study found the variability of cycle length in a sample of 141 women varied from 22 to 36 days (Fehrig et al, 2006).
  • 1 in 5 women experiences heavier than average bleeding.
  • As high as 8% of women experience Premenstrual Dysphoric Disorder (PMDD) which causes severe fatigue, irritability, anxiety, and depression leading into menstruation.

Phases

If you know which phase you’re at, implementing a few strategies can help match your training to how you feel in each phase!

Follicular Phase: Day 1 – 14

  • Starts on the first day of bleeding
  • Days 1 – 7 : estrogen rises and iron is low leading to increased levels of fatigue and some aches
  • Discomfort in first half depends on level of cramping and blood loss
  • Increased pain tolerance, endurance, use of carbs as fuel
  • Increased serum growth hormone
  • Boosted energy, elevated mood, feeling more courageous

Exercise Prescription?

Build it!

The second half of the follicular phase may be primetime to build your strength training.

Studies have shown that maximum velocity force generation capacity is higher during this phase. The first days may be marked by fatigue and aches due to rising estrogen and low iron, but the second half of this 14 day time frame is a great time to build to a high training peak!

Ovulation: Day 14

  • The egg is released from the ovary
  • Estrogen is peaking, progesterone starts elevating, testosterone has a small bump in levels
  • Relaxin, a hormone produced by the ovaries, starts to rise making ligaments more relaxed (higher laxity)
  • Body temperature begins to rise
  • Increasing metabolic rate and strength

Exercise Prescription?

An “eggsellent time” (Thomas King, 2019) to hit a personal best!

Not those eggs! Although, your does metabolism does increase during ovulation…

With the combination of the previous phase being a great building period, the bump in testosterone, and low fatigue, ovulation is meant for PBs. However, this is also a time to pay attention to great form. The peaking estrogen (specifically estradiol) and rising relaxin levels may contribute to higher injury risks. Studies looking at the higher incidence of ACL (knee ligament) injuries in women, noted that significant more laxity is present in the ovulation phase than the follicular phase, and ACL injuries occur 4-8 times more in this phase. 

Luteal phase: Day 14 – 28

  • Estrogen decreases, progesterone continues to increase
  • Body temperature is greater than average
  • Increased fat metabolism with low insulin sensitivity and decreased use of stored glycogen
  • Increased water retention leading to bloating
  • Lower levels of serotonin, which may lead to depressed mood and irritability

Exercise Prescription?

Work on improving technique, building muscular and cardiovascular endurance, and fat loss (if desired) due to the metabolic state.

During the luteal phase, moderate volume and moderate intensity bouts mixed with shorter during and higher intensity bouts may help to regulate progesterone.

Premenstrual syndrome may occur during this phase which can mean bloating, fatigue, irritability, depressed mood, and tender breasts.

Exercise may help regulate the drop of serotonin decreasing the PMS symptoms of depressed mood and irritability.  High volume of high intensity exercise will decrease progesterone which may distort or disrupt the menstrual cycle. Moderate volume, moderate intensity, and shorter duration, higher intensity bouts of exercise regulates progesterone secretion and can aid with irregular periods.

The Exceptions

Menopause

With such little knowledge regarding the interaction of strength training and menstruation, even less is known about menopause and strength training. The most frequently researched outcome is bone health, with strength training during menopause helping to maintain good bone density, thus helping to prevent osteoporosis during this time.

Female Athletic Triad

The Female Athlete Triad is a condition that may occur in highly physically active girls and women. It involves low energy availability, with or without disordered eating, as well as menstrual dysfunction and low bone mineral density.

In extreme training and/or in reduced nutrition, a female athletes’ body fat percentage may be so low that they may lack enough cholesterol to produce estrogen. Lowered estrogen levels can block egg production and the menstrual cycle can be delayed or paused (amenorrhea). The decreased estrogen levels also affect bone rebuilding and can lead to an increased risk of osteoporosis.

Summary

To positively influence your workouts, understanding your hormonal fluctuations is key. Some of the negative effects of the menstrual cycle may be regulated with exercise, with dedicated exercise leading to long-term changes in hormone levels. This means that, for the best results, you should be dedicated to moving and making it a habit. To harness your cycle, track the process, pay attention to the way you feel, and, if comfortable, communicate with your strength coach.

Interested in Strength Coaching to help you set that PB? Get in touch!

~Angie 🏋🏽‍♀️

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