People in our current society tend to drink all day long, thirsty or not thirsty. However, when we look at our evolution, we have never done this. Our ancestors didn’t have a 24/7 opportunity to have a drink.They only drank when there was an opportunity to drink and drank as much as they could until they were completely saturated, just as we still see today in wild animals migrating from well to well.
So, there were frequent episodes of mild thirst with thus relative dehydration of the body.This maintains our sense of thirst! Thirst has therefore throughout evolution created a unique stress response in both animals and humans. Mild thirst will increase the hormone Oxytocin, the so-called “binding hormone” and will also decrease the activation of the HPA axis (hypothalamic-pituitary-adrenal axis) or the so-called stress axis and thus the production of cortisol. The neuroendocrine response to mild thirst appears to be responsible for reducing restlessness, anxiety and aggressiveness.
Feelings of thirst are controlled from the hypothalamic nuclei that receive their information via neuronal pathways over the water and sodium balance of the intra-and extracellular environment as well as from the intrathoracic baroreceptors that detect blood volume.
Maintaining and optimizing the thirst sensation is necessary to obtain optimal hydration. This would encourage weight loss through, among other things, optimal mitochondrial metabolism resulting in higher basal metabolism.
Suboptimal water absorption is associated with various health problems such as metabolic syndrome, cardiovascular disease, diabetes and even cancer. Dehydration activates our RAAS (renin-angiotensin-aldosterone system) which simultaneously stimulates our HPA axis and thus puts us under stress.
Optimal hydration is orchestrated by different parts of our brain. The neuroendocrinological pathway of feeling thirstyiswell known, but how we feel that we are satiated with drinking is less well understood. This would involve the amygdala (fear center) and prefrontal cortex because ‘overdrinking’ is a danger to our body and therefore stimulates our fear center.
Therefore, the saturation point is reachedwhen it starts to bedifficult to swallow whendrinking an amount of fluid (bulk drinking). The advice given is: stop drinking if the swallowing effort is three times greater and if swallowing feels very unpleasant.
If people want to learn a natural drinking habit, they should not only drink less throughout the day, but especially less frequently so that an optimal thirst reflex is re-established, which contributes to an optimal water and electrolyte balance and a weakened stress reaction