It sounds like an impossibility, but in actuality, exercising too much can contribute to physiological changes in the body that can lead to putting on more pounds. Yikes, Did I say exercising can cause weight gain, Yes, I did, and it’s true!

Physical movement is a significant facet to foundational health. In fact, research has shown that regular-to-moderate-intensity exercise reduces the risk of heart disease, helps the body manage blood sugar and insulin levels, improves mental health, lowers the risk of cognitive decline, strengthens bones and muscles, and can even encourage better sleep.

The keyword here is: moderation

In the exercise world, moderate-intensity activity is anything that increases heart rate up to 50–60% higher than its rate when at rest. The American Heart Association recommends adults get at least 150 minutes of moderate-intensity aerobic physical activity per week (that’s 30 minutes, five days per week). Light exercise will not provide as much benefit, and excessively vigorous exercise can cause our body’s stress hormone, cortisol, to do counterproductive things.

The relationship between cortisol and exercise is complicated, but recent research has unearthed how they interact, especially with intense exercise. It is widely known that physical activity is a short-term stressor that temporarily increases the amount of cortisol circulating in the bloodstream, in part because cortisol is necessary to increase blood sugar levels. This increase feeds the muscles, supplying energy to them. However, in more detail, what is now being studied is how long, more intense exercise can cause a detrimental and sustained rise in cortisol, which can – if occurring long term – wreak some havoc on the body.

So, what does high cortisol do to the body? Although cortisol is necessary for proper functioning, when cortisol levels are elevated over time, they can lead to symptoms including fatigue, blood sugar imbalances, brain fog, low mood, sleep disturbances, menstrual changes, thyroid disruptions, blood pressure changes, and also weight gain! This weight gain – sometimes nicknamed the “spare tire”– accumulates in the belly region and can become the most stubborn weight to lose. Ironically, the activity one may do to lose weight can contribute to maintaining it. But don’t dismay if you are an endurance athlete or you love your current exercise regimen. There are lifestyle measures, food, and natural health products that can help modulate the effects of cortisol and prevent weight gain, and potential burnout that rising cortisol levels may create. Eating lots of fresh fruits and vegetables, doing deep breathing exercises, and using specific herbal extracts such as ashwagandha (Withania somnifera) have been proven to support healthy cortisol levels.

Ashwagandha, or Indian ginseng

 A randomized, double-blind, placebo-controlled study found that high concentrations of a full-spectrum ashwagandha root extract exhibited a significant reduction in stress, and was proved safe and effective in reducing serum cortisol levels. Ashwagandha is an excellent choice for athletes to balance cortisol to support overall performance and can be found in essential natural health stores. The general recommended dosage is 300 mg per day, but always discuss using supplements with your health care professional, to confirm you are taking the right amount for you!

Moderate exercise is an effective way to support a healthy weight, blood sugar levels, mood, and the cardiovascular system, but too much of anything can sometimes be a “not-so-good” thing. Be mindful of how much stress, whether mental or physical, you are putting on your body and implement measures to optimize cortisol levels to keep yourself healthy, fit, and belly-fat free.

There are three main factors in exercising that should be recognized, especially if you are active and want to be proactive in your hormone health and weight management.


Greater intensity exercise has been shown to cause more significant spikes in cortisol. And training with heavier weights has also been seen to create a more dramatic increase in cortisol than training with lighter weights.


Activities longer than 1.5–2 h cause a higher rise in cortisol in the body. In part, it’s because cortisol levels don’t get a chance to drop back to normal when they should, and this poses a problem for endurance athletes and affects recovery times between training sessions.


Interestingly, time of day can also influence the cortisol-exercise relationship. Because cortisol levels are generally their highest in the morning, research suggests that intense exercising for a long duration may lead to even higher levels.