Remember the COVID workouts on social media that we were doing? These were mostly High-Intensity Interval Training (HIIT). In today’s fast-paced world, HIIT has gained popularity and is the ideal option for busy women, looking for a time efficient and effective way to boost their fitness. But with the increase in cortisol that HIIT causes, is it a suitable method of exercise for everyone, especially women who suffer with hormone conditions?

 

What is HIIT?

High-Intensity Interval Training (HIIT) is a type of training approach that includes short periods of intense or maximal effort exercise (typically around the 60-second mark), and short recovery periods.

Typically, HIIT involves repeated exercises that are performed in quick bursts with the aim of maximal work. This is followed by a short period of rest, or a low intensity exercise as recovery (any where between 10-20 seconds).

It is a challenging and time-efficient approach to fitness has become a game-changer for many, as it’s shown to boost metabolism, burn fat, weight loss and improve cardiovascular fitness. Remember the Joe Wicks workouts? These were HIIT based.

HIIT is not for the feint hearted!

Before we dive into the connection between HIIT and female hormones, we need to understand cortisol.

What is Cortisol?

If you’ve spent any time on social media recently or have a hormone condition, you’ve probably heard the word ‘cortisol’ mentioned quite a lot. Influencers tell us to avoid HIIT because it spikes our cortisol levels, but research seems to say otherwise. So what is the deal? Can we do HIIT, or should we avoid it?

Before we dive into the connection between HIIT and female hormones, we need to understand cortisol.

Cortisol is the scientific name for our stress hormone. Whenever we experience any form of stress, the body produces cortisol. It is our adrenal glands (located by our kidneys) that produce the hormone, but it is our pituitary gland (located at the base of our brains) that control if, when and how cortisol is made and released into the body.

It is important to know that cortisol isn’t a one trick pony, it plays a significant role in blood sugar control, metabolism, blood pressure regulation and more. It isn’t only produced by a near-miss in the car, or running late for an appointment, cortisol can affect by our emotional, mental and physical states. Our bodies are incredibly smart and are very sensitive to any changes in cortisol levels.

 

The Connection: How HIIT Impacts Female Hormones

The two primary players are estrogen and progesterone. These hormones are responsible for regulating the menstrual cycle, maintaining bone density, and supporting various aspects of health, including mood and metabolism.

How HIIT Impacts Female Hormones

What the influencers online won’t tell you, is cortisol is produced no matter what type of exercise we do. This is a completely normal response to our body undergoing any kind of physical challenge. The potential issue with HIIT and female hormones, is that it requires maximal effort with minimal recovery time. Meaning that throughout the whole exercise session, our cortisol levels are consistently firing and being pushed higher, potentially impacting the balance of other hormones.

The key hormones that are impacted by this cortisol increase is estrogen and progesterone.

If you didn’t know already, we’ll fill you in. Estrogen and progesterone are two major hormones that impact many aspects of our lives as women:

  • Regulating our menstrual cycle
  • Maintain our bone density and protect us from bone loss
  • Keep our pelvic floor muscles in good condition
  • Help us to produce eggs to get pregnant
  • Limits inflammation
  • Controls cholesterol levels
  • Helps our brain to communicate messages effectively, including the release of cortisol
  • And so much more.

 

On the note of estrogen, progesterone and our brains releasing cortisol, as you’ve probably guessed by now, they are all linked. 

You may have heard that the body likes routine and to be ‘relaxed’? This is absolutely correct. Prolonged periods of stress and a continuous hit of cortisol can result in hormonal-imbalance. 

In some cases, HIIT can be the root cause of this hormone imbalance, from a continuous cortisol release, causing our hormones (not only estrogen and progesterone) to suddenly be all up in the air and out of whack.

 

The increased cortisol and it’s impact on progesterone and estrogen doesn’t happen over night.

Our bodies are incredibly smart and will deploy many tactics to try and even out these hormone fluctuations. But with continuous HIIT and despite our bodies best efforts, of a sudden we begin noticing negative symptoms that are impacting our day-to-day lives and well-being.

You may notice feeling tired more than usual, changes to your menstrual cycle or acne worsening or beginning to arise (more on this later), but it isn’t just the female hormones that the effects of HIIT and cortisol may influence. 

It influences a whole plethora of hormones! Too many to name, but one worth a mention:

Testosterone imbalance – In women, testosterone plays critical role in maintaining muscle mass (slightly different to men), supporting our bone marrow produce red blood cells that transport oxygen, managing our metabolism, weight and so much more. With this out of balance, you may notice an impact with a reduced sex drive, irregular periods, infertility and trouble maintaining a stable weight.

On that note, let’s dive into the benefits and potential pitfalls of HIIT on your hormones:

 

Benefits of HIIT Training for Women

Let’s start with the positives!

Enhanced Insulin Sensitivity

It isn’t all doom and gloom. Over a 12 week+ period, HIIT will improve insulin sensitivity, which is excellent news for those with type 2 diabetes, insulin sensitivity and potentially Polycystic Ovary Syndrome (PCOS). When insulin sensitivity is enhanced, the body can better regulate glucose (sugar), which may have a positive impact on the balance of hormones such as insulin, estrogen and progesterone. In addition to this, research has shown that HIIT has a positive impact on your metabolic rate (meaning how efficient your body is at burning calories).

Mood

One of the great reasons for doing HIIT in our opinion! Regular HIIT workouts may improve mood and alleviate symptoms associated with hormonal fluctuations. There is a type of hormone called endorphins that are released whenever we feel stressed in order to calm us down and combat the cortisol. Remember the stress that HIIT puts the body under? Equally, we will get that feel-good endorphin boost! These feel-good hormones produced by the body post HIIT-session will enhance your mood and alleviate symptoms like mood swings, anxiety, and depression. There is nothing like that feeling after a maximal effort HIIT session!

 

Potential Pitfalls of HIIT Training for Women

Amenorrhea Risk – AKA losing your period

One of the primary concerns surrounding HIIT and female hormones is the potential of causing irregularities to your menstrual cycle, particularly losing your period. Particularly strenuous exercise routines without the right nutrition support can disrupt the delicate balance of our hormones, causing irregular periods or even missed cycles. Although HIIT’s association with amenorrhea is not entirely understood, it may be attributed to the increased stress hormone cortisol and testosterone, which can interfere with regular hormonal fluctuations as well as the hormones that keep your menstrual cycle going.

Cortisol and Hormonal Harmony

While HIIT will elevate cortisol levels, the relationship between cortisol and female hormones is pretty complex. Cortisol can indirectly influence the production of sex hormones like estrogen, progesterone and testosterone (yes, women have it too!).

In response, your body may prioritise managing persistent stress over its reproductive functions. For women with hormonal conditions like PCOS, this can exacerbate your symptoms.

Some symptoms of hormonal imbalance:

  • Unexplained fatigue
  • Feeling irritable
  • Anxiety or depression
  • Irregular periods
  • Acne
  • Hair loss or hair thinning
  • Decreased libido
  • And more…

This isn’t the case for everyone, however. For many women, HIIT doesn’t impact their health or well-being, and many women maintain hormonal balance. It is luck of the draw.

 

Minimising the Impact of HIIT Training on your Hormones

As with any form of exercise, it’s essential to prioritise safety and the long-term well-being of your body while reaping the rewards of HIIT. But with all that we have mentioned, you may be feeling a little confused as to whether HIIT is for you, or not.

Here are some guidelines to help ensure a balanced approach to HIIT training, with hormone balance at the forefront:

    1. Take an individualised approach

      It is crucial to  know the impact of HIIT on hormones varies from person to person, and what works for your friend likely will not work perfectly for you, and visa versa. Listen to your body and adapt your training accordingly. If you notice irregularities in your menstrual cycle or other symptoms of hormonal imbalance (such as unexplained bloating, puffiness, increased fatigue, feeling faint etc) you need to adjust the intensity and duration of your workouts.

    2. Tailor the work and rest time in your workout

      If you love HIIT, but are noticing some mild hormone imbalance symptoms, try adjusting the length of time that you are working, and the length of time you rest between exercises. The longer rest period and shorter work time will slightly lessen the cortisol response.

    3. Optimise your nutritional support

      Proper nutrition is key to hormone balance, whether you’re an athlete or a recreational exerciser. You need to ensure you’re consuming adequate nutrients to support your workouts and your hormones; are you eating enough carbohydrates and healthy fat sources?

    4. Make sure you are having adequate recovery

      HIIT places significant energy and demands on the body and requires a lot of effort. You need to give your body the time it needs to recover from the HIIT session. Remember that overtraining can lead to hormonal imbalances, so aim for at least 48 hours between intense workouts.

HIIT places significant energy and demands on the body and requires a lot of effort. You need to give your body the time it needs to recover from the HIIT session.

Remember that overtraining can lead to hormonal imbalances, so aim for at least 48 hours between intense workouts.

 

The Verdict: HIIT and Female Hormones

The impact of HIIT on female hormones can be confusing and is very individualised.

While some women may experience disruptions in their menstrual cycle or hormonal imbalances with sustained HIIT workouts, others will enjoy the benefits of enhanced metabolic health and mood boosters with no interruption to their health.

The key to a harmonious relationship between HIIT and your hormones really is a personalised approach and monitoring how these workouts impact you.

We aren’t telling you to avoid HIIT altogether, and we aren’t telling you to make this your sole exercise source. You know your health and your body best, so it is down to you to make the decision.

Try incorporating HIIT into your fitness routine, but be mindful of your body’s signals and adapt your training to align with your needs and goals. Remember that hormone balance is crucial for overall health, and maintaining it is a priority.

By striking the right balance between intensity and self-care, you can harness the incredible power of HIIT while safeguarding your hormonal well-being.

Frequently Asked Questions

Read more about this topic

How does high-intensity interval training (HIIT) affect cortisol levels in the body?
When we complete a High Intensity Interval Training (HIIT) workout, our cortisol levels rise and will peak toward the end of the workout. After 12-hours, your cortisol levels will be back to normal.
What are the hormonal benefits of incorporating HIIT into my fitness routine?
Research has shown that after 12-weeks of regular HIIT, your insulin sensitivity is likely to increase and your thyroid-stimulating hormones become more efficient. This means your body will become better at regulating itself.
Can HIIT workouts help regulate insulin levels and blood sugar?
Yes! Research shows that regular HIIT training will increase your insulin sensitivity and therefore it is likely that your blood sugar will be lower. These benefits are excellent for people with insulin resistance and type 2 diabetes.
Are there specific HIIT exercises that are better for balancing hormones?
There are no HIIT exercises, or exercises in particular that will balance your hormones.
What is the connection between HIIT and thyroid hormones?
You have two hormones called Thyroxine and Thyroid-Stimulating Hormone (TSH). Thyroxine is released by the thyroid, which TSH stimulates the thyroid to do. HIIT elevates your TSH and therefore allows Thyroxine to be released more. Overtime, this means your thyroid is likely to become more efficient.
How does HIIT impact estrogen and progesterone in women?
Regular HIIT workouts, without sufficient recovery or nutrition that supports your body and your workouts can result in decreased levels of estrogen and progesterone.
Does HIIT training have a different hormonal effect on men and women?
Yes. While both genders can benefit from HIIT, the hormonal responses are different. Research suggests that HIIT may lead to greater testosterone increases in men, potentially contributing to muscle growth, whereas women may experience muscle growth, but not as much. Women will experience changes in estrogen levels that can affect menstrual cycles.
Can HIIT workouts improve testosterone levels in men?
One of the body’s responses to a HIIT workout is a temporary increase in testosterone, this is the case for men and women. As men have a higher level of testosterone, it is likely that HIIT workouts will further increase his testosterone levels immediately after the workout. There is some research that suggests HIIT may be better at increasing testosterone levels than continuous training. However, it is important to remember that this is a short-term adaptation, and a male’s testosterone level will return to it’s baseline, the increased will not be continuous.
Are there any potential hormonal imbalances to watch out for when doing HIIT?
Yes, but the only way to know this is to look out for the symptoms of hormone imbalances. This depends on your specific hormones and how your body responds, but if you are concerned about hormone imbalance when completing HIIT workouts regularly, we suggest you keep a diary of when your sessions are, how hard you worked, and how you feel and any symptoms you are experiencing. We recommend you do this for at least 12-weeks.

To read more on hormonal imbalance and HIIT, read our blog here .
How often should I do HIIT to see hormonal benefits?
This depends on a number of factors, but as a blanket recommendation, you need to complete HIIT 3 times a week, for a minimum of 12-weeks to see hormonal benefits in your blood work.

References

Research further

References
Abassi, W., Ouerghi, N., Ghouili, H., Haouami, S. & Bouassida, A. (2020). Greater effects of high- compared with moderate-intensity interval training on thyroid hormones in overweight/obese adolescent girls. Hormone Molecular Biology and Clinical Investigation, 41(4), 20200031. https://doi.org/10.1515/hmbci-2020-0031

Santos, I. K. D., Nunes, F. A. S. D. S., Queiros, V. S., Cobucci, R. N., Dantas, P. B., Soares, G. M., … & Dantas, P. M. S. (2021). Effect of high-intensity interval training on metabolic parameters in women with polycystic ovary syndrome: A systematic review and meta-analysis of randomized controlled trials. Plos one, 16(1), e0245023.

Dote‐Montero, M., Carneiro‐Barrera, A., Martinez‐Vizcaino, V., Ruiz, J. R., & Amaro‐Gahete, F. J. (2021). Acute effect of HIIT on testosterone and cortisol levels in healthy individuals: A systematic review and meta‐analysis. Scandinavian journal of medicine & science in sports, 31(9), 1722-1744.

Irandoust, K., & Taheri, M. (2019). Effect of a high intensity interval training (HIIT) on serotonin and cortisol levels in obese women with sleep disorders. Women’s Health Bulletin, 6(1), 1-5.

Mohammadi, S., Monazzami, A. & alavimilani, S. Effects of eight-week high-intensity interval training on some metabolic, hormonal and cardiovascular indices in women with PCOS: a randomized controlled trail. BMC Sports Sci Med Rehabil 15, 47 (2023). https://doi.org/10.1186/s13102-023-00653-z

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