How much water should you drink per day?

How much water should you drink per day?

23
Feb 2022
Nutrition

<text-size-medium>Our bodies constantly lose water through sweat, urination and breathing. So to prevent dehydration, we need to get plenty of water from food and drink every day.<text-size-medium>

But how much water should we drink per day?

As a general rule of thumb, we should aim to drink at least 35ml/kg of our body weight.  For most of us, that’s between 2-4 litres of water every day. For example, an 80kg male needs 80x35ml = 2,800ml or 2.8L of water/fluid everyday. However there are many factors such as our training, sweat rates, diet and environment that will ultimately affect how much water we need.

Why it’s important to stay hydrated 

Water transports nutrients and waste products around our bodies, regulates our temperature, acts as a lubricant in our joints, and plays a role in most chemical reactions happening in our bodies. So hydrating effectively can reduce our risk of picking up infections and illnesses, limit declines in our cognitive performance, and help us avoid unnecessary headaches or rises in our core temperature. It’s therefore crucial to both our health and physical performance.

How much should you drink before, during and after exercise?

Pre-exercise:

Drink 5-10 mls of fluid per kg of bodyweight 1-3 hours before your workout. For example, a 60kg female would drink 0.3-0.6 litres of water 1-3 hours before exercising. 

If exercising in hot conditions, consider adding some electrolytes to your water. 

During exercise:

Drink to thirst! Your body is clever and will let you know when it’s thirsty. For most of us, this will be a few gulps or mouthfuls every 10-15 minutes.

Post-exercise:

Rehydrating after training replaces what we’ve lost through sweat, which is a combination of both fluids and salts. To help measure this we can weigh in before and after a workout to determine how much fluid we need to rehydrate effectively. It is best to replace every lost kilo with between 1-1.5 litres of fluid. If it’s hot or you’re an especially heavy sweater, go with 1.5 litres per kilo. No matter the volume it is also important to include some electrolytes also to replace the salt we lost through our sweat. Also, don’t feel like you have to drink all of this straight away, it’s best we tackle your rehydration over a 1-6 hour period (depending on the volume of fluid we need to hydrate). 

Dr. Sam Impey

Performance Scientist

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