Can Too Much Exercise Be A Bad Thing?

As with most things in life, moderation is key. Moderate exercise can improve cardiovascular health, help regulate blood sugar and blood pressure, strengthen bones and muscles, help us maintain body weight, and improve flexibility and coordination in everyday life. In excess, however, for some women who are trying to conceive, exercise can put extra stress on the body, and in turn, fertility. 

Your fertility journey is unique and your current exercise routine might be proving beneficial. However, when the hypothalamic-adrenal-pituitary (HPA) axis (the system that manages your stress) is taxed from everyday life, undereating, stressful jobs and/or family, daily toxic burdens, etc., a stressful exercise routine may be doing more harm than good. This is what I like to call “no place for a baby” mode. 

Continue reading to understand how the HPA-axis is connected to your fertility, how our modern lifestyles impact reproductive hormones, how to tell if you are exercising too much, and other ways to get the benefits of exercise without locking your body into “no place for a baby” mode.

The HPA-Axis And Its Connection To Fertility

The hypothalamic-pituitary-adrenal axis (HPA axis) is a neuroendocrine system made up of three parts – the hypothalamus, the pituitary gland, and the adrenal glands. Together, these glands control the body’s response to stress by regulating many physiologic processes like digestion, metabolism, mood, the immune system, and reproductive health. This axis goes back and forth between two modes:

1. the sympathetic nervous system, often referred to as the “fight-or-flight” mode (or as I like to call it in my Fueling Fertility program “no place for baby” mode) and

2. the parasympathetic nervous system, often referred to as the “rest-and-digest” mode (aka “welcome baby” mode).

When the body is put under excess stress from one or multiple sources (including too much exercise), the HPA axis assumes we’re in danger, down-regulating our reproductive hormones and activating “no place for baby” mode. In pre-modern times, this would’ve been an evolutionary advantage – running from a tiger is no time to stop for sex and definitely not a safe place for babies! We can be thankful that rogue tigers aren’t a stressor for most of us today, however, we have replaced the tiger with chronic, low-grade stressors in today’s non-stop, always on-the-go lifestyle, which triggers the same response. This can be a frustrating delay in your fertility journey.

Modern Day “fight-or-flight” Mode

Excessive exercise looks different for everyone. Whether your workouts take an hour or several hours, are daily or every other day, the key component of overtraining is lack of adequate rest and presence of other chronic, low-grade stressors. These stressors could be as sneaky as weekly dinners with your (pushy) in-laws, eating a nutrient-poor diet because you’re too busy to sit and eat decent meals, not getting enough sleep, feeling overwhelmed at work, stressing about stop-and-go traffic on your daily commute, swiping through your social media feed and comparing yourself to everyone and their mom 24/7… you get the picture.

Together, this trifecta of overexertion, perfectionism, lack of recovery, and external pressures constantly activates our fight-or-flight response which is largely governed by two little organs called the adrenals. This leaves our bodies continually trying to adapt to the stress when they can only handle so much.

To keep up with the modern day “fight-or-flight” mode, the brain tells the adrenals to pump out cortisol 24/7 to deal with this constant stressed state. You might feel like superwoman during this time — kicking butt in your job, working late nights, waking up early to work out and on top of your social game. After years or decades of this overdemand on the body and overproduction of cortisol to keep up, the adrenals just can’t keep up any longer and cortisol production eventually burns out.  

This is when you may begin to feel the difference. Instead of feeling like you got a good handle on everything, you may begin to wonder why you just can’t get up at 5am for that workout anymore, or why recovery is taking longer than before, or why you don’t feel rested even after a full night of sleep. Low cortisol levels may now be to blame.

While the adrenals were once thought to get “fatigued” we now know this is not actually what happens, but instead can be along a spectrum of either overworked or underworked.

The spectrum below is a representation of what can happen when you (a) have stress-induced hypercortisol (high levels) and eventually (b) chronic stress-induced hypocortisol (low levels). This IS NOT the same as a serious medical condition of high cortisol called Cushing’s Disease or a state of low cortisol called Addison’s. Instead, these two sides of the spectrum are a state of adaptive cortisol as a result of modern day “fight-or-flight” mode, AKA “no place for a baby” mode.

How Can You Tell If You Are Exercising Too Much?

TAKE A LOOK AT THOSE ADRENALS

Adrenal insufficiency is typically characterized by low levels of cortisol,1 which can manifest as: 

• Feelings of fatigue
• Sleep troubles (falling or staying asleep)
• Feeling tired but wired at night
• Waking up tired, no matter how long you sleep
• Feeling like you cannot function without your morning cup of coffee
• Feeling like your energy crashes mid-afternoon
• Loss of sexual desire
• Depression and/or anxiety 
• Feeling like you’re always waiting for the other shoe to drop
• Sugar, caffeine, and/or carb cravings
• Morning nausea
• Brain fog
• Decreased concentration
• Digestive issues
• Stubborn weight gain around the midsection
• Irregular menstrual cycles
• Weakened immune system 
• Muscle weakness

If caught early on, adrenal insufficiency can be reversed fairly easily. However, symptoms are not usually recognized as adrenal insufficiency until 90% of the adrenal cortex (the area of the adrenal glands that releases cortisol) has been affected,2 at which point more serious health conditions could be at play, such as diabetes, high blood pressure, high cholesterol, and autoimmune conditions. If you’re chronically stressed, fatigued, or burned out, it’s time to check on your cortisol levels via a salivary four-point cortisol test (my favorite is the DUTCH test, which also takes a deep dive into your main fertility hormones).

Low cortisol is extremely common in athletes, likely due to overexercising, but it’s also associated with (2):

• Perfectionism
• History of severe physical or emotional trauma
• Prolonged stress
• Jobs in which the individual feels powerless
• Shift work
• Hypothyroidism
• Diet high in refined flours and sugars
• Long term low-carb diets

LOW ESTROGEN

In addition to wearing down the adrenal glands, excessive exercise can also affect the hypothalamus, a structure in the brain that links your nervous system and your hormones.

When the HPA axis is working correctly, the hypothalamus releases gonadotropin-releasing hormone (GnRH), which stimulates the pituitary gland to release follicle-stimulating hormone (FSH) and luteinizing hormone (LH). These hormones are essential for follicle growth, ovulation, and preparation of the uterus for implantation. When a follicle is stimulated by FSH, it releases estrogen, which supports follicle maturation and stimulates growth of blood vessels and storage of nutrients in the uterus in preparation for pregnancy should it occur in that cycle.

Under excess stress from exercise, however, secretion of GnRH is suppressed, leading to decreased production of FSH, LH, and estrogen.3 Because estrogen is needed for follicle maturation, low levels of estrogen can reduce fertility. 

What does low estrogen look like? Symptoms include:

• sleep troubles
• headaches or migraines
• mood swings
• depression and/or anxiety
• a period that is less than 3 days long
• frequent UTIs
• painful sex
• low libido
• not ovulating or having cycles
• hot flashes or night sweats

If this sounds like you, take a good look at the often overlooked stressors around you. Are you in modern day “no place for a baby” mode? Estrogen is a goldilocks hormone; we want it just right, otherwise you won’t be feeling like your best self and your fertility may suffer. 

AMENORRHEA

While amenorrhea, the lack of a menstrual period, is an obvious symptom of low estrogen, many women with low levels of estrogen show no symptoms. In one study of exercising women, researchers found that as many as 50% of women who exercise 2 hours/week have subtle changes in their menstrual cycles, such as anovulation (meaning a menstrual period occurs but no egg is released) or luteal phase defects (which is when the luteal phase is too short, usually indicating the woman has low levels of progesterone)(4).

In case you need a refresher, the menstrual cycle is broken into two phases: the follicular phase and the luteal phase. The follicular phase is the first half (pre-ovulation), during which an egg follicle grows and matures under the influence of estrogen. The luteal phase is the second half (post-ovulation), during which the uterine lining thickens to prepare for implantation under the influence of progesterone. 

What is important to note about these subtle menstrual changes is that they are subclinical, meaning that the menstrual cycles seem normal based on appearance and length, that is of course unless you are practicing the Fertility Awareness Method.

You might be thinking, “I exercise. Does that mean I’m at risk for subfertility?” Not necessarily! Subtle changes in your menstrual cycle, like anovulation and luteal phase defects, can impact your hormones and therefore your fertility, however, they are easily addressed with changes in diet and lifestyle 

• Red flags that you may be exercising too much:
•  I often feel really exhausted; I might describe myself as “burned out,” “crispy,” or “fried”
• My hormones are all over the place, and my cycles are really irregular
• I have little (or no) sex-drive
• I often feel stressed or overwhelmed; I’ve been under stress for weeks (or months or years)
• I feel cold all of the time; I have to wear sweaters even when nobody else is

If you relate to the above, it might be a good time to re-evaluate if your current exercise routine is still serving your fertility. If you’re feeling concerned, intrigued, or have been TTC for over a year and still aren’t pregnant, join us over in the Fueling Fertility Tribe to find your root causes of subfertility and improve pregnancy rates. 

Exercise vs. Movement

Purposeful, high-intensity, sweat-inducing exercise can be a great contributor to a healthy lifestyle; but in certain circumstances, it can also wear on your HPA axis, reducing cortisol and estrogen, and adding frustration to your fertility journey.

During times of excess stress, try to keep in mind that sometimes movement is more beneficial to your health than exercise. This doesn’t just mean taking the stairs instead of the elevator, but making time in your day to move and breathe with purpose at a lower intensity:

• Walking: Walking is a simple and often overlooked form of low-stress movement. It improves circulation, strengthens muscles, improves sleep, and can be done from practically anywhere! If you can, try getting outside for your walk rather than using a treadmill. The fresh air and vitamin D help increase energy levels and improve mood.
• Yoga: Gentle yoga is a great way to improve your strength, balance, and flexibility. Because yoga incorporates elements of meditation, it can help relieve stress and improve sleep.
• Cycling: Nicola J. Renaldi, PhD and author of No Period. Now What? recommends that TTC women engage in exercises that keep their heart rate below 130 bpm. Cycling at a moderate intensity can help you get your sweat on without the joint stress that comes with other aerobic activities like running.
• Swimming: Swimming requires the use of nearly all your muscle groups, providing a great whole-body workout without straining your joints. It can also be done at a range of intensities, allowing you to find what works best for you.

There’s plenty of ways to get in a good workout – gardening and/or yard work is my favorite way to get some movement (and also my vitamin D for the day)! Housework counts too! I highly recommend getting an Oura ring. Not only will it pick up on these other types of movement, but it will also tell you when your body is in need of some recovery time!

The types of movements listed above are in no way an exhaustive list of “fertility-friendly” forms of exercise. What works for your fertility and your hormones, and what relieves your stress might be different from someone else’s. Remember, there is no one-size-fits-all approach to exercise or fertility. In my Fueling Fertility Tribe, you are able to find out if you are indeed in “no place for a baby” mode and how to get out of it.

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