Never Mind the Bullocks, Here's the Science (8 page)

Depending on the sport, there are four possibilities with regard to sugar and electrolytes. You will need (1) sugar and electrolytes; or (2) just sugars; or (3) just electrolytes; or (4) neither sugar nor electrolytes.

In the first situation, a person needing both sugar and electrolytes might be a marathon runner, who will burn energy
and
sweat a lot. Marathon runners, American Football players and male competition tennis players can sweat fluids at over 2 litres/hr.

In the second situation, a person needing mainly extra sugar might play a so-called intermittent sport in cold weather. They stop and start a lot, and so burn up energy, but might not sweat a lot. Depending on the position played, this could be someone in amateur soccer or tennis. Mind you, ‘serious’ amateurs could push
themselves hard and sweat a lot, and so be shifted up to the first category of needing both sugar and electrolytes.

A person in the third category—who would need only electrolytes (and water, of course)—might be an athlete sweating in a sauna, in order to keep their weight down to a class limit. This can be dangerous if the person takes the dehydration too far—and is not recommended.

People who go for a 10 minute jog around the park every morning fall into the fourth category. They would not really need any extra sugar or electrolytes, just H
₂
O. On the other hand, they might enjoy the taste of the sports drink (even though it’s more expensive than petrol, volume for volume).

Advantages of Sports Drinks

Sports physiologists agree that some athletes in prolonged exhaustive sports definitely need a combination of sugars and salts. Sports drinks also help athletes engaged in moderate to intense activity of an hour or more. Athletes also hydrate better with a sports drink—they tend to consume more, and the water is better absorbed. And if the athlete is low on energy before the start of the event, the carbohydrates in the sports drink can help maintain the glucose levels in the blood better. And, surprisingly, just having the taste of sugars in the mouth can make athletes perform better.

Test cricketers can get dehydrated after a hot day of intermittent activity, mostly spent standing on the cricket field. Surprisingly, there have been cases where the cricketers did not rehydrate overnight, and so began the next day on the cricket field already slightly dehydrated. Sports drinks could help here.

Sports physiologists also agree that drinking pure water does not flush away electrolytes, and that most people who exercise for less than an hour do
not
need sports drinks.

Rinse Mouth to Perform Better!

It seems perfectly reasonable that you can improve your sports performance by consuming some fuel (e.g. sugars). But, strangely, it also seems that you get the same effect from simply rinsing it around your mouth, and then spitting it out!

The study was carried out by Dr E.S. Chambers and colleagues from the School of Exercise and Sports Science at the University of Birmingham in the UK. They worked with eight trained cyclists, who had fasted for six hours. The cyclists had to perform at 75% of their maximum workload for about one hour. They swished their mouths with a liquid eight times during that hour and, on each occasion, spat it all out into a bowl after ten seconds. The liquid either contained sugars or, if it had no sugar, it tasted sweet thanks to the addition of saccharin and aspartame (artificial non-calorie sweeteners).

The results were amazing. When the exercising cyclists swished their mouths with saccharin/ aspartame water, they performed at a certain level. But when they swished 6.4% carbohydrate (sugar) solution in their mouths, their performance improved by an astonishing 2-3%.

Why? We don’t really know. We do know that individual muscle fibres will fatigue after lots of work. And we also know that there is some poorly understood central brain control of ‘fatigue’. Another part of this study looked at brain activity. It found that a part of the brain involved in ‘reward’ became active when the mouth experienced a swish with the sugar solution.

Drink Too Much…

Sports physiologists also agree that it is possible to drink too much.

A tragic example of this occurred in the 2002 Boston Marathon. (Coincidentally, sports scientists wrote a paper in
The New England Journal of Medicine
on that very marathon.)

A few months before the marathon, newspaper advertisements for a major sports drink encouraged marathon runners who might enter to drink at least 1,200 ml/hr, or else ‘…your performance could suffer…’. A marathon is the classic case where a sports drink can help. Two-thirds of the 766 runners provided a blood sample at the end of the marathon. Of those, about 13% had drunk so much liquid—more than they had lost in sweating, breathing, etc—that they had actually gained weight and had diluted their blood sodium to somewhat worryingly low levels. Low sodium levels cause symptoms that include: ‘headache, vomiting, swollen hands and feet, restlessness, undue fatigue, confusion and disorientation (due to progressive encephalopathy), and wheezy breathing (due to pulmonary oedema). When plasma sodium falls…(further)…the chances increase for severe cerebral oedema with seizure, coma, brainstem herniation, respiratory arrest, and death.’ One competitor, 28-year-old Dr Cynthia Lucero, actually died because her sodium levels were too low, from drinking too much. The autopsy report stated that her death was due to ‘ingesting too much Gatorade’.

Mind you, death can also happen by drinking too much fluid of any type, and in situations unrelated to sport. Fatalities have occurred in workplace drug testing (where people have tried to ‘flush’ drug residues out of their bodies to avoid detection in their urine samples) or drinking contests (such as a radio station-sponsored competition in which the last person ‘standing’ before having to urinate wins a prize). And it’s always
more of a risk with those who have a smaller body mass (e.g. women).

Indeed, some people wrongly think that it is impossible to drink too much, and that drinking too much cannot harm you.

It is important to understand your body, and how it behaves in any sport you do, and to drink the correct amount (not too much, not too little). You can use your change in body weight as a guide, and assume that a loss of 1 kg means that you have lost 1 litre of sweat. It’s a rough approximation, but it’s close enough.

You Might Need It…

Yes, sports drinks have their advantages—especially if you work out for an hour or more. And, of course, they can help if you sweat profusely.

One study looked at voluntary drinking in boys who were exercising hard for a few hours in the heat. If the water had some added flavouring, it tasted nicer so they drank more of it and did not get so dehydrated. And water with added carbohydrates and salt prevented the dehydration altogether.

However, you don’t have to sweat huge amounts to benefit from a sports drink. There is mounting evidence that taking carbohydrates immediately before and during high-intensity events lasting an hour or more can enhance performance. If you are a swimmer training for two hours at a time in temperate water, you may not sweat a lot, but the extra fuel is helpful. The swimmer could, of course, eat a meal, but it’s quicker and easier to drink rather than eat when you are training hard. The sports drink also has the benefit of being optimised for quick emptying from the stomach.

Besides helping those engaged in one-hour sports with low to moderate sweat losses, sports drinks can also help those in long events in cooler weather (e.g. cross-country ski events).

You Might Not Need It…

Water drinks (with additives) are
hot.

There are dozens of different brands in petrol stations, gyms, supermarkets and health food shops all waiting for you to buy them. But the majority are not proper sports drinks, with the appropriate amounts of sugars and salts. They are merely flavoured water with added caffeine or just plain flavoured water—all promoted with lots of advertising.

Good sports drinks that are well formulated (e.g. Gatorade and Powerade) do help athletes who regularly exercise for an hour or more. They can be very useful. But they do not do a lot for the person who goes for an occasional short jog. The discriminator for the beneficial use of sports drinks is your physiological need. For example, if you exercise at a moderate to high intensity for an hour or more, you need to consider whether you need to replace brain and muscle fuel, or fluids, or both.

So yes, rehydrate with sports drinks when you exercise for an hour or more in warm conditions, but not too little or too much, or else you will risk watering down all your hard work. And if you exercise only occasionally, and just for a short time, leave the pixie dust to the fairies…

Dehydrated = Mad

Our family has spent a lot of time in the Outback. We have, over the years, crossed 15 of the 17 deserts in Australia.

Way back in 1993, we were at the Three Ways Roadhouse near the Gulf of Carpentaria having a feed. I ran into a bloke called David, who had ridden in on a battered motorbike. We got talking and, after a bit,
he told me how he and his mate Ken had ridden their bikes along the full length of the Canning Stock Route a few years earlier.

I was pretty surprised, because this stock route is hard going. It runs some 2,000 km between the top right-hand corner of Western Australia, and the lower left-hand corner, in a mainly north-south direction.

The reason they survived was because they had a rule that they wouldn’t go to sleep until they had a wee.

David (on a 600cc XT Yamaha Ténéré) and Ken (on a Honda XR 500) started at Halls Creek and headed south along the Canning Stock Route to Meekatharra. It took them two weeks.

They were well prepared. They timed it so that their trip centred around the full moon in October 1987. This was so that if things got bad, they could ride out at night to either the east or the west, to the nearest town. They rode in two shifts – from 3 am to 11 am, and from 4 pm to 6 pm. In the middle of the day, they rested.

Each bike had 25 litres of petrol in the tank, and carried two 20-litre jerry cans as well. They used 60 of their precious 65 litres getting to Well 35. (There are 51 wells, from Well 1 at the southern end to Well 51 at the northern end.) They had arranged for a 200-litre fuel drop at Well 35, and took on 120 litres, but had to leave 80 litres behind.

They didn’t carry an emergency radio – there’s not a lot of room on a motorbike.

They each carried a total of 20 litres of water, in various containers. It wasn’t a lot of water, but they filled up at the three or so wells that they passed each day. They were drinking 25 litres each per day. Riding a motorbike in sand is like jogging, because you’re standing up all the time, so you work hard and get thirsty.

They ate army rations (one Day Pack each day, $25 each) because they were nutritionally well balanced, and because the rations were not dehydrated. If they ran low on water, they didn’t want to have to use it to rehydrate food.

They wore compasses on their arms, and mounted strip maps of the stock route on their handlebars. And their lives were saved because of the rule that they had made on a previous occasion while riding across the Simpson Desert.

They’d noticed that even though sometimes they were actually quite thirsty, they didn’t drink enough water. And so they made up a rule that they simply would not go to sleep unless they had urinated. You see, in most cases your body will let you urinate
only
if you are well hydrated (body fluid balance is actually a very complicated field of study, but this short sentence is a mostly correct summary).

It turned out to be a pretty rough trip. It was 43°C at Alice Springs, and it had to be hotter than that along the route. It was so hot that the valves in the engine stuck.

Early on, around the third and fourth days, they each got injured. Ken hit a termite mound with his right foot. (When a four-wheel drive vehicle travels the Canning Stock Route, it follows the wheel tracks, and only a few centimetres or so of mudguard actually projects outside the wheels. But on a motorbike, a lot of the motorbike and your feet project out on either side of the wheels.) Ken took his shoe off that night. His foot swelled up overnight, and he could hardly get his shoe back on the next morning. So he left his right shoe on for the rest of the trip. The next day, David broke three toes on his right foot, and he left his right shoe on for the next week.

A few days later, at the 11 am stop, they arrived at an empty well. They had each drunk 15 litres of water, and had only 5 litres each left. They didn’t stop, and pushed on to the next well which was quite close, only about 20 km away.

They soon began to experience heat exhaustion. David described it as the feeling you get when you drink five nips of rum really quickly. He was breathing very fast, felt dizzy, and was so uncoordinated that he kept falling over. But because they were so irrational from the dehydration caused by the heat exhaustion, they just kept on riding and falling over, and riding and falling over, sustaining more injuries with each fall, and laughing uproariously at the fun of it all. They arrived at the next well (which luckily had water) around midday.

‘We decided we deserved a rest after that, so we didn’t do the evening run.’ They lay down and rested, and drank. ‘When you’re buggered, you don’t feel like drinking, but you know you have to,’ David said. So they stuck to their rule and kept on drinking water. Gradually their heads became clearer, and they realised what terrible shape they were in, and how close they had been to death. But they still hadn’t urinated so they kept on drinking. And finally after sundown, around 8 pm, eight hours after they had started resting and drinking, they finally urinated and went to sleep.