22nd July 2014
If you’ve been finding your workouts a little more sweaty lately – thanks to this glorious spell of hot humid weather – you may have been thinking about having a sports drink or an electrolyte tablet to replace your electrolyte losses. The truth is, you (most probably) don’t need them. Here’s why.
You have ample sodium in your body so, for most activities under two hours, you should not need to replace sodium sweat losses until after your workout. Electrolyte replacement is only beneficial when sweat losses are high and prolonged, and you lose around 3 – 4g sodium.
According to the International Olympic Committee consensus conference, if you’re exercising for less than 2 hours and sweat losses are not excessive, extra electrolytes will not speed fluid absorption, nor benefit performance. However, sodium will increase thirst and make you want to drink, as well as promote fluid retention.
Although sweat can taste ‘salty’, you don’t actually lose that much sodium during most activities lasting less than 2 hours. Sweat is always more dilute than body fluids, which means that you’re losing proportionally more water than sodium. For most workouts, it’s more important to replace water than to replace sodium. Only for high intensity workouts longer than 2 hours or when you’re exercising in extremely hot humid conditions (when your sweat losses are exceptionally high) will you need extra sodium.
Consuming sports drinks or electrolyte drinks during shorter workouts probably won’t harm your performance, but you could be consuming something you don’t really need. In one study, bananas were shown to be as effective as a 6% carbohydrate sports drink in fuelling performance in a 75km cycling time trial.
Save your money and try this instead:
- If you’re exercising less than 1 hour, drink water (or simply add a dash of sugar-free cordial or squash to your water bottle).
- If you’re exercising (at a moderate-high intensity) longer than 1 hour, add 50 ml cordial or 65 ml squash to a 1-litre water bottle and top up with water. This provides around 20 – 30g sugar per litre (2 – 3 % drink). Double this for a 4 – 6% drink.
- If you’re exercising in hot humid conditions or for longer than 2 hours, add 1.25 – 2.5g (1/4 – ½ teaspoon) of ordinary salt. This will provide 500 – 1150mg of sodium.
- Alternatively, just have milk or a milk-based drink, or a banana with yogurt (plus a few salted nuts) as a post-exercise snack. All foods contain sodium and milk has been shown to replace fluids more effectively than sports drinks.
For more, see Food For Fitness (4th edition)