Hydration when running

As you run, you will generate heat, it's inevitable. Your body's reaction to this to maintain body temperature is to start sweating; the sweat evoporates off your skin, taking heat with it. Your body is good at doing this, and short-term doesn't present any problems.

However, if you are running for longer periods of time, it's going to give you problems with dehydration. Exactly how quickly and how badly you become dehydrated depends on many factors, such as,

• How well-hydrated you were in the first place. Look at how much you have drank over the last 24 hours, and what colour was your urine? Dark urine implies you are dehydrated, light to clear urine suggests you are well hydrated. Make sure you consider the full 24 hours prior, and not just the last hour or two.
• How warm and humid it is. As you'd expect, in warm weather you are going to overheat quicker, the result is you will end up sweating more. In humid climates, there is already a lot of moisture in the air, so the effectiveness of sweating is reduced, the result being more sweating to compensate.
• Your effort. If you are doing a hard run, it's natural to expect that you will sweat more. Consequently you will become dehydrated quicker.
• It also depends on the individual. Some individuals seem to sweat very little, while others may literally be dripping with sweat, so make sure to take this in to account as well. As you start running more and more, your body will adapt to maintaining body temperature efficently.

In today's society we are constantly reminded to make sure that we stay well-hydrated. The truth is that short-term dehydration while running will not do us any harm. If you start well-hydrated, and make sure you consume enough liquid after finishing, it will not give you any problems at all.

The answer to this kind of question is down to the individual, and of course your local climate. In all but the most extreme cases, if you are out running for less than 45 minutes, you don't need to take water with you. Anything longer than that in warm climates and you will probably benefit from taking water with you.

If you are new to running, you are probably only running for up to 30 minutes. In that situation, I would assume you don't need to take water with you. You may feel thirsty through your run, but in my experience it will mostly be a psychological effect as opposed to a physical one.

Consider this, if there was a plentiful supply of water before and after, how long would you be happy to sit outside without water for? Would you be happy to sit for an hour? If so, why would you need to take water when running for half that time? Do you really think you are going to become significantly more dehydrated running for half the time compared to sitting?

I find that the natural tendency of new runners is to always take water with them, without necessarily considering if they actually need it or not. I don't like taking water with me, and only do it if I absoulutely have to; I find carrying water pulls my running gait off, a weight in one hand makes you unbalanced.

If you feel more comfortable taking water with you, then do so by all means. But make sure you consider whether you really need to take water with you or not; experience will tell you that.