We believed that stress was only psychological. Science shows that it also depends on the amount of water you drink

We all know that facing a tight deadline, a job interview, or a heated argument trigger our stress levelsand it is nothing more than a basic evolutionary response. However, science is beginning to see that the intensity with which our body reacts to a stressor depends not only on our psychology, but on something as fundamental as the amount of water we drink throughout the day.

It has been investigated. A recent study published in the Journal of Applied Physiology has put on the table the relationship that exists between the general state of hydration and the reactivity of cortisol to acute stress. In other words, a dehydrated body is a body that overreacts to the problems that may arise on a daily basis.

Cortisol. To understand this finding, we must first look at the ‘place’ where our stress is regulated, which is the hypothalamus-pituitary-adrenal axis. This system is activated when we face a psychosocial threat that culminates in the release of cortisol, which is our main stress-related hormone and can be easily measured through saliva.

Logically, cortisol at normal levels is necessary for survival, but the problem arises when it remains high for a long time, which begins to generate many problems in our body and also confronts us with anxiety disorders.

Hydration. This is where water comes into play, since dehydration, even mild, is not just having a dry mouth but biologically, it is a major stressor. When we do not drink enough water, our blood volume decreases and its concentration increases. The body perceives this as a threat to homeostasis and responds by releasing hormones to try to compensate for this lack of fluid, such as vasopressin, which causes us to urinate much less to avoid ‘wasting’ water.

Threats. What science demonstrates here is that when we subject a person who is poorly hydrated to psychological stress, the body experiences a double threat. Here the nervous system is already dealing with the physiological stress of lack of water and, if we add to that an external stressor, such as a work problem, the cortisol response shoots up much more abruptly than in a well-hydrated person.

But we are not facing something completely isolated, but rather there are many studies who have found a relationship between state anxiety and hydration. If we go to the purest physiology, it makes sense, since the brain is made up of 73% water and that is why it is extremely sensitive to a drop in the amount of liquid drunk throughout the day.

It is not the same for everyone. Human biology is rarely a simple equation, as the salivary cortisol response to psychosocial stress has high variability between people. Age, sex, coffee consumption, smoking or steroid levels act as modulators of this hormone, for example.

However, the state of hydration is now emerging as one of the most easily modified variables by ourselves. We can’t change our age or erase a family problem, but we can make sure that our fluid intake doesn’t make things more difficult for our nervous system.

Images | engin akyurt

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