August 19, 2016

Running and biking in the summer heat: Advice for athletes on drinking fluids

During summer seasong, when, how much and what to drink is a hotly debated topic among athletes. If you drink too much, you have all that extra water weight to schlepp around. If you only drink water, you can end up electrolyte deficient (hyponatremic). But if you drink too little, you can become dehydrated. How do you find out how much fluid you actually need? ultraSports-expert Friederike Feil has some advice for you.

How much you should drink during exercise, depends on many factors: weather, training state, and how much you drink prior to exercise. We know that during physical activity the stomach can’t handle more than approximately 600 ml (20 ounces) of fluid per hour [during cycling, up to 800 ml (27 ounces) because there is less stomach jostling]. Thus, it’s nor worth it to drink more than this quantity.

Drinking by feel


The most recent research shows that drinking based on your feeling of thirst is the best solution. That means if you listen to your body, you will perceive how much you should drink. On very hot days, the body can give signals that it needs more too. Simply pay attention to your body.

Body compensates for light dehydration


Your ability to perform starts to decline when you are 3-5 percent dehydrated. If you weight 80 kg (176 lbs.), that would mean a loss in body weight of 2.5-4 kg (5.5-8.8 lbs). The body compensates for smaller losses in body fluids.

Careful of large quantities of plain water


If during strenuous exercise you drink only water, your electrolyte balance gets worse and worse: In sweat, you lose minerals, such as sodium. If you ingest large quantities of mineral-free plain water (e.g. 5-6 liters over the course of a competition or all at once), you’ll over-dilute your body’s fluids and this state can be fatal. If you are losing large quantities of sweat is therefore important that the fluids you ingest also contain minerals, particularly sodium.

When do you need sports drinks?


Sports drinks are needed when you are physically active for 60-90 minutes or longer at one time. Sports drinks should thus always contain carbohydrates and some protein. The relationship of carbohydrates to protein should be approximately 3-to-1. In addition, sports drinks should contain at least 800 mg of sodium per liter. Sodium protects from exercise-induced cramping and speeds the ingestion of water and carbohydrates in the intestines.

Apple juice spritzers are not for athletes


Apple juice spritzers are not recommended as a sports drink because the natural acidity can cause stomach and intestinal problems. You can end up with painful cramping too. An additional problem is the high content of fructose, which can result in performance deterioration. It can also make you slow down considerably since too much fructose decreases the blood flow to muscles.


Recommended Products for your summer running or biking adventure:


When it’s hot outside your clothes should be lightweight and highly breathable. Here’s what we recommend for a bike or running adventure in summer:

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