How much water should you drink a day?
We often underestimate the importance of drinking enough water, when resting as well as during intense physical activity.
Yet the body, made up of 60% water, needs topping up with water all the time because the amount of water you drink has a considerable impact on your day-to-day health.
Effects of not drinking enough water
It's estimated that slight dehydration, corresponding to only 1% loss of water, generates a feeling of tiredness.
After 2% water loss, your body performs less well when you exert yourself and muscles lose 20% of their power. At the same time, certain faculties can be significantly reduced. Even your cognitive performance can be affected.
Water loss greater than 10% is life-threatening as your body will go into a state of shock.
Drinking enough water every day is therefore vital for both your overal health
and your mental and physical powers (concentration, endurance, agility, etc.).
Water loss in the body
When at rest in a temperate climate, you should drink 1.5 litres of water a day. Water loss throughout the day occurs through the following ways:
1. Evaporation through the skin = 15%
2.Evaporation through the lungs = 15%
3. Elimination through urine = 60%
4. Elimination through faeces = 5%
5. Elimination through sweat = 5%
It's therefore essential to drink plenty of water throughout the day. Food and the body's metabolic production provide 30% and 10% of your water needs respectively, so you need to provide the remaining 60% by drinking fluids.
How much water should you drink before physical activity?
It's recommended that you drink 1.5 litres of water. This pre-hydration is particularly important.
In adults, 60% of body mass is made up of water. It varies depending on whether you're male or female: on average, the figure is 65% for men and 60% for women and this evolves during the course of your life. The older you get, the less water your body contains. Therefore, water content represents 75% of the weight of a newborn and 50% of the weight of an elderly person.
Water's key roles
Your body needs water to function. Here are the main roles of water in the human body:
● Water acts as a vehicle. It's found in your plasma which transports nutrients, oxygen and CO2 through the body.
● Water has a regulatory role. It has an impact on the volume of plasma and therefore allows correct blood pressure to be maintained which is essential for the
heart to work well.
● Water has a thermoregulatory role, allowing it to regulate the temperature of the body. Through sweating, water allows the heat generated from the body to escape.
● Water maintains hydroelectrolytic balance, which allows the body to alter the concentration of sodium, potassium and calcium.