Hydration
Much of our body is made up of water (around 55-60%) so it’s no wonder that its an integral part of our health.
- If you are a 91kg male then you are about 54kg of water.
- If you are a 59kg female then you are about 33kg of water.
And if you are a baby then you are around 75% water.
Different cells contain different amounts of water:
- Bone is about 22%
- Adipose (fat) tissue is about 25%
- Muscle and brain tissue are about 75%
- Blood is about 83%
- Eyes are about 95%
When do we need water?
As with everything, our bodies regulate thirst and will let us know when we require water.
We obviously get thirsty when:
- Its warm
- We’ve eaten something salty
- We’ve drunk alcohol
- We’ve been sweating
There might be a bit of a delay between losing fluid and feeling thirsty. Even a slight decrease in hydration can have an effect on our cognitive function and performance.
So how much water should you be drinking?
As a baseline, most adults require around 3 litres (12 cups) of water per day.
If its warmer you may need an extra 500ml (2 cups) and if you are exercising you may need up to 6 litres (24 cups) per day
How do i calculate my basic fluid requirements?
For every kilogram of bodyweight, you should be ingesting 30-40ml of water.
This is just a baseline, obviously environmental and other factors will determine whether you require more or less.
The effects of water loss can have a detrimental effect on the body.
0.5% decrease can lead to increased strain on the heart.
1% decrease reduces aerobic performance.
3% decrease reduces muscular endurance.
4% decrease reduces muscle strength, motor skills & can cause cramps.
5% decrease can cause heat exhaustion, cramping, fatigue and reduced mental capacity.
6% decrease can cause physical exhaustion, heatstroke, coma.
10-20% decrease can lead to death.
For most people just consuming plain water is fine, but for some athletes, its beneficial to drink sports drinks to help replenish their glucose & electrolytes.
For moderate activity under 2 hours and / or high intensity activity under an hour you should follow these guidelines:
- Consume 0.5-1L (2-4 cups) of water during the activity.
- Consume 0.5-1L (2-4 cups) of water after your workout
- Consume 0.25-0.5L (1-2 cups) of water with each meal.
For moderate activity lasting longer than 2 hours and / or high intensity lasting longer than an hour you follow these guidelines:
- Consume 0.25-0.5L (1-2 cups) of water 30-60 minutes before training.
- Consume 30-45g carb + 15g protein + electrolytes (sodium and potassium) in 600ml of water every hour during activity.
- Consume 30-45g carb + 15g protein + electrolytes (sodium and potassium) in 600ml of water afterwards.
- Consume 0.25-0.5L (1-2 cups) of water with each meal.
If you follow these simple guidelines above you will be able to keep your body hydrated and perform at your best!
References:
- The Essentials of Sport & Exercise Nutrition by Precision Nutrition.
