Keeping your drink

By Anna Niec

Staying well-hydrated is easy with the range of drinks available. Photo by CPL Belinda Mepham

How many of you think about staying well hydrated? Drinking enough fluids is important to keep up good energy levels, to prevent kidney stones, gout and to help flush impurities out of the blood stream.

Staying hydrated is particularly important for physically active people because when we exercise we lose more fluid through sweat and increased breathing.

Let’s take a look at the fluid losses during exercise and ways in which we can replenish. Physical exercise increases fluid loss

When we exercise, our heart rate increases, as does our breathing to accommodate for increased oxygen needs. Our core temperature goes up and this requires cooling – we start to sweat. Lets take a brief look at the amounts of fluids lost during some types of exercise.

Typical fluid loss for different exercises

Exercise	Temperature degrees	Sweat loss ml/hr
soccer male	20-28	925ml
netball female	20-28	720ml
rowers male	32	1980ml
rowers female	32	1390ml
runners long
distance	not specified	850ml

Staying well hydrated.

If you are playing any of the sports in the above table you could estimate the amount of fluid you need to drink during training to avoid dehydration. Just multiply the amount of fluid lost in an hour by the total time of exercise for example, if you played soccer for two hours and you are a male then you would lose approximately 925ml x 2 = 1850ml of water during the game.

To stay well-hydrated you would need to drink 1850ml of water during the two hours of soccer and that means drinking about a glass of fluid every 15 minutes.

This may be difficult for some people so drinking before and soon after training may be the way to go to avoid bloating.
For those of you who exercise heavily and enjoy a variety of sports, the best way to assess your fluid needs is to monitor your fluid losses during each of the main training sessions.

You would only need to do this once providing that you stay with the same exercise routine.

Record the difference. Change your weight in kilograms to grams by multiplying by 1000. Keep in mind that 1g of body weight is equal to 1ml of fluid lost.
The difference in your body weight at Step 3 represents the amount of fluid that you have lost during exercise and that is the amount of fluid you need to drink during the exercise to stay well hydrated.
To avoid bloating drink fluids uniformly throughout the exercise and get a head start by drinking about half to an hour prior to exercise. Continue to drink well for the rest of the day.

Hydrating vs Dehydrating Fluids

Some drinks are able to replenish body fluids faster than others. Drinks can be divided into hydrating and dehydrating.
Drinks that contain caffeine are dehydrating as caffeine is a diuretic – it actually speeds up fluid loss. Drinks, which contain caffeine, include tea (both black and green), coffee and most soft drinks.
Hydrating fluids don’t contain caffeine and are not high in protein and other colloidal particles. Water is the best hydrating fluid found in nature.
Sports drinks are synthetic drinks designed to improve the speed at which water is absorbed from the stomach. Studies show some, but not a great difference, between water and sports drinks in their ability to replenish body fluids.
The difference may be relevant for athletes competing at their peak.

Watching your levels of hydration

Hydrating fluids	Dehydrating fluids
water, fruit juice,	coffee, tea most
cordial, clear soup	soft drinks

Nutrition for health message

Stay well hydrated. Aim to drink at least half of your daily fluids as water and other hydrating fluids.