Water is vital for all of your body’s systems to function. When you are dehydrated, your body will will experience critical malfunctions, that could be fatal if left untreated. Dehydration causes a drop in blood volume.
Our bodies are made of up to about 65% water, and blood accounts for most of that. This can cause your body to compensate by increasing your heart rate and overheating your muscles. The imbalance will drop your energy levels, and you will lose mental clarity, as your body focuses on trying to conserve fluid.
It takes 30 minutes for consumed fluids to reach your muscles and nerves. The body will trigger a number of symptoms when it starts to become dehydrated, and culminate in a total and complete system shut down if ignored.
Initial symptoms dehydration is a dry mouth, exhaustion or sudden sleepiness, thirst (which can be confused with hunger), dry skin, headache, and nausea or dizziness.
Severe dehydration symptoms that require a medical emergency are extreme thirst, confusion and irritability, sunken eyes, abnormally low blood pressure accompanied with rapid heart rate, fever, and even delirium or unconsciousness.
If you are endurance exercising for longer than 3 hours, you’ll need to hydrate more frequently, and you’ll need to hydrate with electrolytes. Water can also be dangerous if consumed frequently and quickly in large amounts, causing a condition called hyponatremia. It can cause a sodium imbalance, which is extremely dangerous as electrolytes are responsible for nerve function.
Ditto on really hot days when you are outside. If you are you are consuming large quantities of water, eat something small to help regulate your electrolytes. You don’t need much to offset the effects of excessive water consumption.
For hot weather or high intensity exercise, you will need to replace every pound of water lost through sweat with about 24 oz of water to maintain hydration.