Hydration during running is not as complicated as you may have been led to believe.
It pretty much goes like this:
When you run, you sweat. The more you sweat, the more your blood volume decreases. The more your blood volume decreases, the harder your heart has to work to deliver oxygen to your working muscles.
It really doesn´t sound like a good thing, but luckily nature implemented a safety measure - thirst... More on that later.
Athletes almost never find themselves at dehydration levels sufficient to cause severe consequences to your health, but your wellbeing might be at risk. What is considered normal levels of dehydration will make you feel pretty uncomfortable and will surely cause you to slow down in whatever sport you are doing - this is not new to anyone that have been running for a while.
Of course, drinking while you run or exercise will greatly reduce the effects of dehydration. The big question, one that have been debated for a long time, is what you should drink, how much, and when?
Earlier, athletes were told to drink as much as possible during exercise, and at least to drink enough to completely offset dehydration (i.e. to prevent any reduction in body weight). Lately this has proven to be false information for the thirsty runner. There are mainly two reasons.
One - It is actually possible to drink too much during exercise. If you force yourself to swallow more fluid than your body really needs while running, you may end up with stomach problems and in extreme circumstances it may cause water intoxication, also known as hyponatremia.
Second - Research has shown that there is no advantage to be gained by drinking to completely offset sweating. Neither performance nor body temperature regulation improves over a case where you drink when you feel thirst.
The new, new thing with hydration
The new running hydration advice is to do what you always do - drink according to your thirst. As simple as that.
As long as you carry enough drink, and keep it accessible, during your runs, you will naturally drink enough to optimize your performance by doing the simple task of drinking when you are thirsty.
In general, you should not need to drink on exercise with a shorter duration than one hour, but you can - if you get thirsty or just like to have something with you. I personally carry with me a hydration backpack for all my runs or treks, with the added benefit of being able to carry my phone or extra clothes if I need to. I always make sure to carry at least 500 ml. of water as well - even on short runs.
Plain water is in most cases sufficient, but the large variety of available sports drinks offer a few added benefits. Sports drinks replace some of the lost sodium and other minerals that leave your body with the sweat. In addition, sports drinks provide extra energy for increased performance when you need to refill the carbs. Research has shown that sports drinks increase performance significantly in high-intensity and/or long-lasting runs and races.
For most runs, however, water will be more than sufficient. Save the sports drink for when you really want to crank out performance, or you are heading out on those really long runs.
Keeping fluids close and accessible during runs can be a challenge, and there are several options to solve this.
The basic hydration options for your exercise
Hydration backpacks - most of these backpacks carry plenty of fluids for even the most grueling runs. They usually come equipped with a fluid bladder and pockets for other soft-bottles or squeeze bottles.
Hydration waist pack - significantly smaller, but also easier to carry and cheaper. The waist pack should not be your choice for the longest runs, as they usually carry less than 1 000 ml. of fluids for even the biggest ones. But usually more than enough for your short runs.
Handheld hydration - usually smaller than even the waist pack, but carries from 250-500 ml. The handhelds often offer a small "pouch" for your keys and maybe a phone. Great for short, fast runs, but too small for the longer ones, if you don´t have access to a refill.
Whatever solution you choose, make sure it fits your style of running, is comfortable to carry and is kept in a convenient place to grab a quick drink. Check out the Wunjo Sports hydration solutions here.
And remember, don’t force down fluids. Drink when you’re thirsty. Have a great workout!