Fatigue
Fatigue can be a symptom of overhydration. It is most common in endurance athletes but is sometimes seen in patients with heart failure and other illnesses. Overtraining can also cause fatigue, which is probably why you are fatigued when overhydrating.
To understand why this happens, we need to know how the body regulates fluid volume. The thirst reflex is triggered when extracellular fluid concentration becomes too high or low. When we drink enough water to compensate for volume loss through sweating, urination, and breathing, thirst goes away. As a result, the body stops producing angiotensin II, constricting blood vessels and stimulating thirst.
In addition to thirst, the body also has a mechanism that kicks in after we have lost more fluid than can be immediately replaced by drinking water. The renin-angiotensin-aldosterone system (RAAS) increases blood pressure by causing blood vessels to narrow and by stimulating the kidneys to retain sodium and water and release potassium into the urine. Angiotensin II also causes adrenal glands to release cortisol and aldosterone, which results in increased blood volume.
When our body fluids are too concentrated or dilute, a message travels to the brain, which then signals us to drink. Drinking enough water and other fluids will help prevent this condition and keep you healthy.
