I last touched on the mechanism of sweating and the dangers of heat build-up in the body.
If you play a sport or exercise out in the heat without sufficient water replenishment (hydration), you will not only decrease your performance but could be setting yourself up for heat exhaustion and eventually heat stroke.
I want to expand on this topic and discuss how much fluid intake is appropriate, what kind of fluid replacement is optimal for different kinds of exercise and time-frames.
There are three main time periods to consider fluid intake: before, during and after playing your sport or workout.
Each of these can have slightly different volumes and composition to consider for the drink you ingest.
Pre-exercise hydration is all about correcting any dehydration or electrolyte imbalance you have from the period before the workout or game.
There can be many reasons for being dehydrated from the previous day, including hot weather, playing a tough game the previous day with insufficient replenishment, and so on.
If you’ve eaten a well-balanced breakfast before working out, you should not need a sports drink prior to exercise – plain water should suffice.
But you can start hydrating as much as three to four hours before your workout.
The specific amount depends on many factors, but a 160-pound person should try to get about 16 ounces of water over this time period, more for a bigger person, less for a smaller one.
Hydration during exercise is influenced by the intensity and duration of exercise, sweat rate, weather conditions, heat acclimatization and a host of other factors.
Professional athletes experiment with different strategies for post-exercise weight-loss and performance levels to try and fine-tune their competition routine.
For most recreational athletes and exercisers, there are a few basics to follow.
First, if the exercise session is less than one hour, water is fine to drink. You normally won’t need electrolyte or carbohydrate replacement.
However, if the game or workout lasts 60 minutes or more and is at least of moderate intensity, it would be advisable to consume a sports drink containing carbohydrates and electrolytes.
Research has shown that long-term aerobic exercise, such as cycling, running or triathlon can benefit with a carbohydrate consumption rate of 30-60 grams per hour. The solution should be no greater than eight per cent concentration otherwise water absorption gets reduced. That’s why fruit juice is not ideal during a prolonged exercise – because it’s too concentrated.
Drinking about eight ounces every 15-20 minutes of exercise should be sufficient, but this can be altered depending on the heat and humidity of the day.
Recovery after exercise can involve many things, but hydration and refuelling are often not given enough importance. The amount of fluid replenishment depends on the temperature, humidity, duration and intensity of exercise, but basically should be about a litre of fluid for every two pounds lost during exercise.
If you know beforehand that the session will be hard or the conditions extreme, it’s a good idea to weigh yourself before and after the session and drink accordingly post-workout.
A couple of pointers: fluid is best absorbed when you drink slowly and gradually as opposed to single, large amounts; sports drinks with a little protein added will help the body absorb much-needed carbohydrates and will aid in rebuilding muscle tissue.
Once again, if the session was particularly hard, or if the athlete has another game later in the day, ingesting sufficient carbohydrate and protein is very important, especially during the first 20 to 60 minutes after the workout.
But the average recreational athlete doesn’t need to be as concerned with the carb/protein issue as much, just get enough fluid and resume regular, healthy eating patterns for the rest of the day.
Kerry Senchyna holds a bachelor of science degree in kinesiology and is owner of West Coast Kinesiology
in Maple Ridge