During vigorous exercise, cortisol levels rise. Really, is that a bad thing?

 

Fitness gurus assert that while milder options like walking help control weight loss, more strenuous exercises like HIIT or running might raise cortisol levels and impede weight reduction. However, cortisol has a far more complex effect in exercise than just being "good" or "bad."

Cortisol, sometimes known as the "stress hormone," is held responsible for everything from burnout to belly obesity. However, it is essential to the body's ability to function. Martine Duclos, an endocrinologist and sports medicine physiologist at Université Clermont Auvergne, asserts that "we die if we don't have cortisol." In times of stress, it helps maintain blood pressure, reduce inflammation, and release energy.

Therefore, why does cortisol have such a negative reputation if it is necessary? Does exercising cause it to go out of control? Here is the real science behind this misunderstood hormone and how it affects your exercise routine.

 

The impact of exercise on cortisol
Not only does cortisol respond to stress, but it also naturally fluctuates throughout the day. According to Travis Anderson, a research scientist at the US Olympic and Paralympic Committee who has studied cortisol as a circadian hormone, levels are at their peak in the morning to aid in waking and alertness. Unless stresses, such as exercise, cause the body to temporarily raise cortisol levels, the hormone progressively decreases during the day.

Although cortisol is not intrinsically bad, chronically elevated cortisol levels can lead to metabolic dysfunction, high blood pressure, and cardiovascular problems. In severe situations, like Cushing's Syndrome, the body overproduces cortisol, which increases body fat, increases the risk of type 2 diabetes, and causes other health issues.

 

Why exercise causes an increase in cortisol
Exercise normally raises cortisol levels because it is a type of stress. This is a vital component of the body's mechanism for promoting mobility, therefore it's not a bad thing. According to Anderson, cortisol makes sure that muscles have access to enough glucose to function.

Researchers discovered that moderate-to-high-intensity cycling workouts caused cortisol surges in a study that looked at 12 active males. This finding is in line with several other studies. The maximal oxygen uptake, or VO2 max, which is the highest quantity of oxygen an individual can utilize during vigorous activity, was used in the study to quantify intensity. For instance, running up a hill would result in nearly 100% oxygen uptake. Cortisol levels rose during cycling exercises at 60 and 80 percent of a person's maximal oxygen consumption, but not during a lower-intensity session at 40 percent.