Hint & Tips
Drink your way to winning performances: the seven secrets of hydration
Brian Mackenzie explains how to keep your body water intact during exercise and perform at a much higher level.
If you wish to perform at a high level, you need to consume fluid. For each per cent of body weight lost due to dehydration, your performance slips by about 2%, and a 2% loss in weight can force your heart rate and body temperature to spiral upward, making strenuous exercise almost impossible to carry out.
If you are going to be exercising for 20 minutes or less, dehydration is not usually a problem, but difficulties can arise during longer exertions. For example, copiously sweating athletes can flush about 1.5 litres of fluid per hour through their sweat glands, a total of three pounds per hour. If these heavily perspiring individuals weigh 150 pounds that is a 2% loss in weight after just one hour producing a 4% dip in performance if no fluid is taken on board. The downturn in performance would be smaller, about 2%, after 30 minutes, but that is still enough to make a difference to serious athletes who are interested in winning.
But what are the rules for fluid intake? How much do you really need and what should your drink be like? To make it easy for you, we have listed the seven rules of fluid intake during exercise below. If you follow these rules, you will keep your body water intact during exercise and perform at a much higher level. (Rehrer 1994)
Rule 1: The rate of passage of water from your stomach into your small intestine depends on how much fluid is actually in your stomach. If there is lots of water there, fluid flow from stomach to intestine is like a springtime flood; if there is little water, the movement resembles a lightly dripping tap. Therefore, to increase stomach intestinal flow (and overall absorption of water) you need to deposit a fair amount of liquid in your stomach just before you begin your exercise. Intake, 10 to 12 ounces of fluid is a good start. This will feel uncomfortable at first, so practice funnelling this amount of beverage into your "tank" several times before an actual competition.
Rule 2: To sustain a rapid movement of fluid into your small intestine during your exertions, take three to four sips of beverage every 10 minutes if possible, or five to six swallows every 15 minutes.
Rule 3: If you are going to be exercising for less than 60 minutes, do not worry about including carbohydrate in your drink; plain water is fine. For more prolonged efforts, however, you will want the carbohydrate.
Rule 4: Years of research have suggested that the correct concentration of carbohydrate in your drink is about 5 to 7%. Most commercial sports drinks fall within this range, and you can make your own 6% drink by mixing five tablespoons of table sugar with each litre of water that you use. A bit of sodium boosts absorption; one third teaspoon of salt per litre of water is about right. Although 5 to 7% carbohydrate solutions seem to work best for most individuals, there is evidence that some endurance athletes can fare better with higher concentrations. In research carried out at Liverpool John Moores University cyclists who ingested a 15% maltodextrin solution improved their endurance by 30% compared to individuals who used a 5% glucose drink. The 15% drink also drained from the stomach as quickly as the 5% one, though many other studies have linked such concentrated drinks with a slowdown in water movement.
Rule 5: A 6% "simple sugar" drink will empty from your stomach at about the same rate as a fancy, 6% "glucose polymer" beverage, so do not fall for the idea that the latter can boost water absorption or enhance your performance more than the former, and do not pay more for the glucose-polymer concoction.
Rule 6: Contrary to what you have heard, cold drinks are not absorbed into your body more quickly than warm ones. However, cold drinks are often more palatable than warm ones during exercise, so if coldness helps you to drink large quantities of fluid while you exert yourself, then keep your drinks cool.
Rule 7: Swilling drinks during exercise does NOT increase your risk of digestive system problems. In actuality, most gut disorders that arise during exercise are caused by dehydration, not from taking in fluid. Dehydration induces nausea and discomfort by reducing blood flow to the digestive system, so by all means keep drinking!
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About the Author
Brian Mackenzie is a British Athletics level 4 performance coach and a coach tutor/assessor. He has been coaching sprint, middle distance and combined event athletes for the past 30+ years and has 45+ years' experience as an endurance athlete.
The following Sports Coach pages provide additional information on this topic: