The Impact of Hormonal Birth Control on Exercise

As fitness professionals we need to be aware of the deleterious effect hormones, that are often unknown or undiscussed, may have on a client’s workout. The majority of personal trainers cultivate friendships, even a closeness, with long-standing clients. Some sessions end up with just as much talking and sharing as weight training. No matter how close we may feel to these individuals, there are often unspoken boundaries when it comes to certain topics. Birth control can fall into this category; once we fully understand the possible effects hormonal contraception can have on a woman’s ability to exercise, how do we broach the topic if we suspect that impact is manifesting?

 

Acknowledging a Hormonal Hindrance

We already know that hormones like testosterone play a role in how we exercise, grow muscles and age. But there are more hormones at play that we typically don’t think about. Progesterone is a hormone found in pregnant women as well as a multitude of birth control devices. A normal part of a woman’s menstrual cycle, progesterone typically does not cause any problems. As with most generalities, though, there are exceptions to this.

A personal trainer and seasoned veteran of both aerobic and resistance training exercises shared her personal journey of discovery. She noticed serious changes in her workouts when she began using either the patch or the ring as methods of birth control. Unusual and significant fatigue seemed to overtake her while engaging in HIIT or circuit training. Her heart rate and respiration skyrocketed; while she was accustomed to experiencing an RPE of 5 or 6 during these times, she found herself closer to an RPE of 9.

In an effort to conceive, the young woman discontinued all birth control, only to find that her former level of energy instantly returned. However, within the first month of her pregnancy, the exhaustion and labored breathing commenced. After researching the phenomenon, she realized what may be responsible for these changes was progesterone. If a trainer notices any new or suspect shift in a highly conditioned client, hormonal fluctuations may be the culprit.

The Science/Action of Progesterone

During a woman’s premenstrual phase, progesterone stimulates respiration through a variety of peripheral chemoreceptors. This leads to greater energy consumption by respiratory muscles that would otherwise be utilized for different muscular activities. Studies have proven how hormonal fluctuations have the potential to alter a female’s airways as well as the inflammatory responses of her lungs. As hormones rise and fall during a typical cycle, new blood vessels in the lungs form and disappear, affecting the lungs’ ability to take in oxygen.

Immediately following ovulation and during the premenstrual phase of the female cycle, pulse rates do tend to elevate. An uptick in circulating blood volume brought on by the thermogenic action of progesterone could be the reason for this increase.

The female hormone progesterone works as an antagonist, countering some of the effects of estrogen, another hormone of significance in a woman’s cycle. In theory, one might expect endurance to be greater in the latter part of a menstrual cycle, when estrogen levels enable the body to utilize fat as an energy source while sparing carbohydrates. However, many women experience a significant decrease in athletic performance during this time of the month. Scientists have noted that elevated levels of progesterone may actually act against the estrogen in women who are more sensitive to their bodies’ subtle shifts. It is believed that this comes about due to an increase in core body temperature.

Sensitive Bodies Exhibit Powerful Reactions

Hormone-based birth control methods work in part by mimicking the effects of early pregnancy. As it happens, a surplus of progesterone is present in a woman’s body during the first trimester, in order to build and sustain a thick uterine lining for the newly formed zygote. Many women experience bouts of labored breathing during these early weeks. As mentioned earlier, progesterone increases the amount of air inhaled and exhaled, which brings on this sensation.

As effectively as these birth control methods work, medical professionals often fail to inform patients of potential hazards associated with use. According to reports by Drugs.com and MedlinePlus, tachycardia, the medical term for a rapid heart rate, can occur as a serious side effect of progesterone therapy. A faster than normal heart rate has the potential of increasing the pressure of the blood as it travels through the cardiovascular system. Hypertension can produce life-threatening results, such as a stroke or heart attack. Progesterone use has also been reported to elicit a pounding sensation of the heart.

Recognizing Dangerous Symptoms

Trainers are accustomed to working with clients who suffer from hypertension, COPD, and sometimes arrhythmias. We would never hesitate to inquire about such medical conditions prior to taking on such a client. We know how to recognize potentially dangerous symptoms and take appropriate action. However, when such symptoms occur in an apparently healthy female who has disclosed that she is free of any cardiorespiratory complications, we typically would not think to consider birth control methods as the root cause.

Asthma, too, can be a hormone-related health issue. Hormones travel through the bloodstream as messengers. In proper balance, they help the body communicate and thrive. However, when hormone levels rise excessively in an otherwise healthy and fit woman, either due to early pregnancy or progesterone therapy, even well-controlled asthma can quickly turn into a medical emergency. We must be prepared to take action. If a new client reveals that she has asthma, suggest she carry her rescue inhaler with her during the workout.

While cases of cardiorespiratory challenges due to progesterone are rare, a little knowledge keeps trainers on their toes. The more we can learn about uncommon situations, the better we can deliver successful services to all of our clients.

Amending the Initial Assessment

Going forward with new clients may be an easier assessment adjustment to make. Our initial intake involves inquiring about medical history and medication. To avoid sounding invasive, you might consider adding a short blurb about how hormonal contraception containing estrogen may cause increased respiration and heart rate, and exacerbate symptoms of asthma. A yes or no answer to whether or not a female client is currently taking such hormonal birth control will then certainly be warranted.

For established clients who you may noted exhibit more labored breathing or elevated heart rate than you expect for their level conditioning, you might share with them an article cited below or verbally mention how you have recently learned of this connection between hormonal therapies and exercise. Without out-right asking if she is on birth control, you can alert her to the potential side effects that she otherwise may not have recognized.

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References:

http://jeb.biologists.org/content/205/2/233

https://pdfs.semanticscholar.org/1eb0/805cc1559d531bc7f13d0f8424102ed20699.pdf

https://www.drugs.com/cdi/xulane.html

https://www.exerciseregister.org/blog/post/breaking%20through%20the%20taboo:%20the%20menstrual%20cycle%20and%20exercise%20performance/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5353821/

https://www.healthline.com/health/shortness-of-breath-early-pregnancy

https://www.health.harvard.edu/decision_guide/shortness-of-breath-in-pregnancy

https://www.plannedparenthood.org/learn/birth-control/birth-control-patch/what-are-disadvantages-patch

https://www.everydayhealth.com/progesterone/guide/

https://www.livestrong.com/article/524086-progesterone-heart-palpitations/