From our complete runner's guide to hydration, comes six hydration Questions and Answers. Subscribers can read the complete guide here - but if you're not a subscriber yet, you can save 30% off the newsstand price right here and get access to all our subscriber content within 30 minutes.
Can I "water-load" before a run?
Loading up with fluid before a race might seem like a good strategy if you’re competing in an ultra distance event or a race where there is little opportunity to drink, or under hot humid conditions, but you cannot achieve hyperhydration by simply consuming large volumes of fluid prior to an event. The body simply excretes surplus fluid and you end up paying frequent visits to the toilet.
However, there is method of hyperhydration that involves the consumption of glycerol along with fluid two hours before exercise. Taken with water, glycerol is a hyper hydrating agent, which, through its strong osmotic activity, drags water into the extra-cellular fluid and intracellular fluid. Although you aren’t drinking any more, in theory your total body water increases and you will be able to maintain blood volume, increase sweating and reduce the rise in core body temperature that occurs during exercise. Studies at the Australian Institute of Sport found that athletes who used glycerol retained an extra 600ml of fluid and improved performance in a time-trial by 2.4 per cent. A few side effects have been reported, however, including gastro-intestinal upsets and headaches.
Can I hydrate with coffee and tea?
Although caffeine may have a diuretic effect at rest, don’t let fear of dehydration come between you and your espresso. In a three-day study at the University of Connecticut in the US, subjects exercised twice a day, drinking water during workouts and regular or decaffeinated cola at all other times. Researchers found no significant difference in hydration status between the two groups.
Are cold drinks better at hydrating than warm ones?
It’s long been thought that cold fluids were better than warm fluids at delaying exhaustion, but research from the University of Minas Gerais in Brazil doesn’t back this up. Athletes exercised to exhaustion in three separate sessions: in the first they were given cold water, in the second warm water and in the third hot water. The amounts were the same each time. Results showed that the temperature of the water did not affect the time it took them to reach fatigue. What fluid temperature does affect, though, is how much you drink. Cold drinks tend to taste better, making you drink more, so keep drinks chilled where possible.
Will a salty snack keep me hydrated?
A salty snack at about 20 miles in a marathon might help your body to rehydrate if you only have access to water. A sports drink is much better because it contains sodium and other electrolytes. Studies at Yale University found that sodium encourages water retention, reduces urine output and so rehydrates athletes better after training.
Do oxygenated waters deliver more oxygen?
Manufacturers of oxygenated water claim that it contains up to 40 per cent more oxygen as ordinary water, and that it can enhance sports performance. These claims were tested in a recent study in the Journal of the American Medical Association when volunteers exercised to exhaustion on two different days, once after drinking the oxygenated water and once after drinking the same brand with oxygen removed. There was no significant difference in performance between the two tests, with the researchers adding that a single breath contains more oxygen than a bottle of oxygenated water.
Should I pour water on my head when it’s hot?
Your skin temperature rises when it’s hot, forcing veins in your arms and legs to dilate and fill with blood, which can’t circulate effectively. This blood can only return to circulation if your skin cools. Sponging or pouring water on your skin lowers its temperature, constricts the veins, and reduces the volume of blood they can store. You don’t get any cooler but increasing the volume of blood filling the heart helps the heart to pump blood round at a lower heart rate. Spraying water on your face might also lower your perception of exertion, according to a study at the University of Birmingham.
You’re better off with the fluid inside you than out. Drinking it will replenish your sweat losses and regulate your body temperature more effectively than sloshing it over your skin. Do both if you want, but gulp a drink if you have to make a choice.
