What should we drink to keep hydrated?

Image: Ed Yourdon via Flickr
Image: Ed Yourdon via Flickr

As we saw last time, you’re better off ditching the “8 glasses a day” rule and following your thirst when it comes to keeping hydrated.

To stop you becoming a dried up husk, water is a great option. Diluted squash / fruit juices are also effective at replenishing water. For many years, it has been said that flat coke is excellent for recovering from dehydration. It doesn’t work. For replenishing fluids, the World Health Organisation recommends that 18 grams of sugar and 3 grams of salt in 1 litre of water form an effective ‘oral rehydration solution’ that should give the “taste of tears”. For anyone who has tried it, flat coke is preferable any day.

The salt and sugar in these oral rehydration solutions not only replace the sugars lost through exertion and the salts lost through sweating, but also help to increase the amount of water absorbed. In the intestines, the body ‘sucks up’ the salt and sugar from the drink through a process called ‘active uptake’, which acts to help pull more water into the body.

Commercial carbonated drinks don’t work this way, however. They have sugar content so high that they can actually have the reverse effect, making dehydration worse. Once again, we see the importance of balance in our diets.

Is that cuppa a bad idea?

We are also told to stay away from caffeinated drinks, like tea and coffee, when we want to rehydrate. Caffeine acts as a diuretic: a drug that makes you wee more. However, when academics tested this theory out, it was found to be more hearsay than science. One experiment found no difference in hydration levels of two groups who consumed either just tea or just water over a 12-hour period. Preliminary research has also thus far found no link between moderate coffee consumption and dehydration. Despite being partial to a cup or three of tea here at Guru Magazine, we know that we couldn’t survive on caffeine alone. (Of course not, you need biscuits/cookies as well! – Ed.)

Sports drinks

Of course, plain water is a bit boring and, as everyone knows, proper athletes need something more. With $9 billion a year being spent on them in America alone, so-called “sports drinks” are big business. They also usually have the word “isotonic” written somewhere on the label. It sounds sciencey enough to impress many of us, but simply means that the drink contains salts and sugars in similar concentrations to the human body, like the oral rehydration solutions described above.

Sports drink manufacturers love to tell us that their drinks are important to improve physical performance, especially when drunk during and after a vigorous workout. And while sports drinks certainly will replenish salts (or ‘electrolytes’) lost through sweating, critics   “there is a striking lack of evidence to support the vast majority of sports-related products that make claims related to enhanced performance or recovery”. Moreover, sports drinks may be doing more harm than good –  , with large quantities of sugar contributing to weight gain. You could, of course, replace your water and electrolytes with homemade energy drinks such as our tear-flavoured juice (above).

There are therefore a whole load of drinks that do the job. While we should be mindful of what is in our sports drinks, we at Guru continue our search to find something that a cup of tea cannot do.

Article by Michael Mckenna

April 24, 2015

Mike is currently doing a PhD in biochemistry at the University of Manchester. When not talking about proteins, he watches an obscene amount of films and enjoys the odd pub quiz.


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