By Kim O’Hare
Temperatures are rising and it is now more important than ever to make sure you are replacing the fluids lost during exercise to prevent dehydration and the development of hyperthermia.
Drinks can also provide a means of supplying additional fuel for the body. The ingestion of water and of carbohydrate have independent and additive effects on endurance performance. Sports drinks have become a multi-billion dollar industry, but there’s no need to break the bank to keep hydrated.
The composition of commercial sports drinks such as Lucozade Sport, Isostar and Gatorade have been formulated on the basis of numerous scientific studies which have established the optimal content of carbohydrate and electrolytes for endurance performance.
Most serious athletes will be aware of the guidelines for fluid ingestion during prolonged exercise and the risks of dehydration. Just drinking more water isn’t a solution as the additional water simply dilutes the electrolytes.
It is recommended that individuals consume a nutritionally balanced diet and drink adequate fluids to promote proper hydration before exercise or competition.
You should drink about 500 ml (about 17 fl oz) of fluid about two hours before exercise to promote adequate hydration and allow time for excretion of excess ingested water.
During exercise, athletes should start drinking early and at regular intervals in an attempt to consume fluids at a rate sufficient to replace all the water lost through sweating or consume the maximal amount that can be tolerated. It is recommended that ingested fluids be cooler than ambient temperature (between 15 and 22*C, 59 and 72*F) and flavoured to enhance palatability and promote fluid replacement. Fluid should be readily available and served in containers that allow adequate volumes to be ingested with ease and with minimal interruption of exercise.
If your workout is going to be longer than a hour or takes place in extreme heat, addition of proper amounts of carbohydrates and/or electrolytes to a fluid replacement solution is recommended. During exercise of less than an hour, there’s little evidence of physiological or physical performance differences between consuming a carbohydrate-electrolyte drink and plain water.
Most commercially available sports drinks contain 60-80g/l carbohydrate and 20-25mmol/l sodium. They also contain flavouring to increase palatability. Typically sports drinks like these will cost around 70-125p for a 400-500mL can or bottle.
Composition of some drinks commonly consumed during exercise
A drink that closely approximates these - at a fraction of the cost - can be made up as follows:
The amounts shown are sufficient for 1 litre of drink.
50 grams of glucose as dextrose monohydrate (available from most chemists).
0.5 grams of sodium chloride (table salt), about 1/7th of a level teaspoon.
1.5 grams of sodium bicarbonate (baking soda), about half of a level teaspoon.
Add the above ingredients to 500 mL of water. Mix thoroughly until completely dissolved.
Add 100ml of a commercially available sugar-free (low-cal) fruit cordial
Finally, add more cold water to top up to a total volume of 1 litre.
If you find the drink to be a little too salty for your taste, then instead of the table salt and baking soda, add 2.5 grams (about one level teaspoon) of sodium citrate. This will provide a similar amount of sodium, but without the salty taste.
Pour the drink into a bottle that can be kept airtight. Store it in the fridge if you are not going to use it on the same day. Use within three days. If you’re concerned about the container you use to store and carry your sports drink, you’ll want to read