This Sunday (May 30th), the Ottawa race weekend had a great day for a race! The half and full marathon runners experienced relatively cool temperatures (< 16 C) – taking some pressure away from worrying about huge sweat losses and during run hydration to help minimize these losses to ensure peak performance. A number of runners have already emailed me to say that they achieved personal bests! But even though the temperature was relatively cool and there was a nice breeze to help cool runners’ bodies down, a hydration strategy was still important! The distance that you run, the pace/speed/intensity of your run, your fitness level, and the environmental conditions all contribute to what you should drink and when you should drink it.
Why are fluids important for distance runners?
- Drinking prior to and during a distance run can help with temperature regulation by preventing heat illness and dehydration.
- Drinking post-run is essential to optimize your fluid balance and ensure that you have enough circulating fluid to maintain blood volume, rehydrate intracellular water and maintain overall water balance.
- Drinking sufficient fluids throughout the day ensures that your kidneys have enough fluid to flush out all the waste products of your metabolism.
Before your run:
- While water will help to ensure adequate hydration before your run, sport drinks not only help to rehydrate, but also ensure that your first source of energy, your blood sugar, is topped-up and ready to race.
- Whether during training or competition, being adequately hydrated is a huge advantage. The following chart can be used as a guideline to ensure you are drinking enough before you run.
How long before a run? How much?
4 hrs BEFORE….drink 5-7 mL/kg body weight
2 hrs BEFORE….drink 3-5 mL/kg body weight
During your run
Sweat rates can range from 0.4 Litres up to 1.8 litres per hour in a heavily sweating, big bodied person. Sweat rates also depend upon on the weather, the duration of your training session, and your training level. With this in mind, some runners find it difficult to consume enough fluid while running to replace the amount lost in sweat and prevent dehydration.
- As a general guideline, drink 0.5 to 1 cup (0.4-0.8L) of fluid per hour.
- Endurance formula sport drinks contain the same amount of carbohydrate as regular sport drinks, but almost twice the amount of electrolytes.
- Although beverages such as enhanced water or low calorie sport drinks help to ward off dehydration, they do not contain carbohydrates, and therefore do not provide adequate fuel during a run.
- Ideally, 15-20 g of carbohydrate per 250 ml is sufficient, with the type of sugar being glucose, sucrose, or maltodextrin with some fructose.
- Too much fructose, such as that found in fruit juice, has been associated with symptoms of upset stomach, nausea, vomiting, and diarrhea in some athletes.
- 125-175 mg of sodium, and 20- 50 mg of potassium per 250 ml is ideal.
After your run
Replacing fluid and electrolyte loses is not only necessary for rehydrating post-run, but essential for athletes in training who may be running again the next day. Sport drinks help you to refuel and rehydrate at the same time.
- Runners should get in the practice of weighing themselves before and after a training session, and monitoring the conditions of their run in order to recognize and replace fluid loss, and ultimately maximize performance.
- Aim to drink 1 – 1.5 L of fluid/kg of body weight lost during exercise.
Powerfuel™ Hydration Tip #1
Ice may improve your hot weather running performance.
Maintaining your running performance in hot weather may be as simple as drinking a slushy drink (ice-slurry) pre-run. Australian research suggests that a slushy drink could give you pretty significant performance benefits due to its effective cooling action compared to water. Runners drinking ice slurries pre-run were able to run for longer than when cold water was taken – likely because the runners were able to absorb more of the heat produced during their run then when cold water was consumed. So……load up on ice chips for your pre-race water bottle when running in the heat.
Powerfuel™ Hydration Tip #2
While water is often adequate, sport drinks are often more effective and provide additional energy and electrolytes to improve performance. Sport drinks are a great way to maximize fluid intake for athletes who do not enjoy drinking water, and therefore ingest inadequate amounts. The electrolytes in sport drinks also help to lock the fluid into the body.
Powerfuel™ Hydration Tip #3 – Train your gut (not just your legs) to run fast!
Training in an environment similar to where you will be competing is critical. Plan to acclimatize yourself to the weather conditions, the time of day, and the sport drink or gel used at that race. Surprises are part of the challenge (and the fun!) but training to your race will ensure that there you can handle anything that comes your way without jeopardizing your performance. Lastly, if you do not know which sport drink will be provided at the race, or if there will be any left when you get to the next station, BYOB (bring your own beverage)! This will ensure that your competition closely mimics your training and you will be prepared for anything. Remember, this is what you’ve trained for (and paid for), so enjoy it!