A big part of what we do at CrossFit Donelson can be categorized as high intensity interval training. HIIT, as it’s commonly known, is a very popular and effective form of exercise, and as such, garners a good bit of criticism from fitness influencers, some of whom even claim to be experts. One of the reasons some people warn against HIIT workouts is elevated cortisol levels. But is this an accurate criticism? And if so, is it even something to fear?
In order to get to the bottom of this, we first need to understand the overall hormonal impact of high intensity interval training, including many positive changes.
Can High Intensity Training Help Your Hormones?
The short answer is yes, HIIT workouts can not only be extremely beneficial to your muscles, bones, and cardiovascular system, but they can also increase growth hormone and testosterone levels, improve thyroid function, and produce more dopamine and serotonin.
These changes are the catalyst to muscle growth, fat loss, and improved mood and sleep quality. As a coach, I’ve seen all of these changes firsthand, with many of our gym members reporting that they feel stronger, look better, and generally feel happier when they regularly attend our classes. Who doesn’t want that?
That being said, one of the criticisms of high intensity training is that it can elevate cortisol levels. Is this true? And why would that be bad? First, let’s clarify what cortisol’s function is in the body.
What Is Cortisol?
Cortisol is a steroid hormone produced by the adrenal glands, and is usually referred to as the “stress hormone.” This is because, among other functions, it manages the body’s response to stress, both physical and emotional.
Even though it’s responsible for other essential bodily functions, such as maintaining blood pressure, regulating metabolism, and helping the immune system, it’s often viewed as a “negative” hormone because of its association with stress.
Do chronically elevated cortisol levels cause health issues? Yes… but do consistent HIIT workouts cause this condition? Based on my research, coaching, and personal experience in doing these workouts myself for over a decade, I don’t think so. Let’s dive deeper.
Effects of High Intensity Training on Cortisol Levels
During high intensity training, your body is placed under an intense physical stress (hence the name). Your heart, lungs, and skeletal muscles are strained, and in response, your cortisol levels rise acutely. While this might sound bad, it’s actually a good thing! This temporary spike in cortisol makes you focused and alert, reduces the inflammatory response, and most importantly, mobilizes energy in the form of glucose and fatty acids.
Much like your heart rate, blood pressure, and body temperature, this rise in cortisol is a short-term effect, and your body will significantly reduce all of these metrics within 30 to 60 minutes of completing your workout, ultimately returning you to baseline over the next several hours. This shouldn’t worry anyone in the slightest, because this is how the body adapts to stress and becomes stronger and healthier over time.
In the same way we strain muscle fibers and they respond by becoming bigger or stronger, our body can adapt to physical stress by lowering chronic cortisol levels over longer periods of time, which can lead to an improvement in all its functions I mentioned earlier, such as metabolism, blood pressure, brain health, immune strength, and fat loss.
Recovery is Crucial to Sustainable Progress
So if high intensity training is so beneficial to your hormones, why the bad rap? Because if you push yourself too hard for too long, your body can become chronically stressed, leading to consistently elevated cortisol levels. Which means the real question everyone should be asking is, “How exactly can I avoid this?”
First, there is a limit to each person’s capacity for training. Frequency, volume, and intensity are the three main dials that you can adjust to your individual tolerance. At CrossFit Donelson, we recommend 3-5 high intensity workouts each week, within the context of our hour-long classes.
Second, the importance of recovery should not be undervalued. This includes sleep, nutrition, low intensity movement, and stress management (both physical and mental). Honestly, anytime you aren’t working out could be considered some level of recovery. Train your body enough to create adaptation, but not too much, otherwise you’ll be moving towards sickness rather than fitness. Again, this is why we recommend 3-5 workouts per week for most people most of the time, which allows for 2-4 days of rest and recovery.
So, is it the high intensity training that causes chronically elevated cortisol? Not really. It’s the combination of overtraining and lack of recovery that leads to this undesirable outcome.
Long-Term Benefits of High Intensity Training
Now that we know the potential pitfalls and how to avoid them, we should mention the importance of high intensity training. In CrossFit, we say that intensity is the “independent variable most commonly associated with maximizing the rate of return of favorable adaptation to exercise.” In other words, high intensity training is the most effective and efficient method to produce desirable results.
These results include improved strength, stamina, endurance, flexibility, power, speed, coordination, agility, balance, and accuracy, as well as correlating health markers, such as muscle mass, body fat percentage, blood pressure, resting heart rate, triglycerides, and blood sugar level.
Our Training Program Can Support You
Since intensity is directly equal to power, we can gather data from our workouts to objectively measure our progress in the domain of fitness, which allows us to continue to dose the appropriate amount of intensity, which is relative to each person’s tolerance.
So how do you strike the right balance of training volume and intensity with necessary recovery? That’s what we’re here for! Our program is designed to challenge each person enough to gradually increase their fitness without overwhelming their body, and our coaches are experts in teaching movements and providing the best scaling or modifications for both beginners and advanced athletes.
Whether you’re an experienced veteran looking to take yourself to the next level, a beginner who wants to dip your toes into the shallow end of intensity, or someone who just wants to enjoy an active and healthy lifestyle, we are the right gym for you! Schedule your Free Consultation with one of our coaches so we can guide you to more health and happiness.
