Skip Navigation

Hydration – Part 1 Dehydration

30 days to go

Our bodies are made up of around 60% water and water is important for many of our bodily functions. It moves nutrients around the body and removes waste products, it is important for lubrication in our joints and is a major element of managing our temperature control through sweating.

It’s not unusual after a day in the hills for me to find myself dehydrated despite drinking regularly throughout the day.  What I notice most is that I feel more tired than I expect and sometimes I might feel thirsty but not always.  Occasionally I get a dull headache.

Other signs include a dry mouth, leg cramps, dizziness or nausea, poor concentration and often people report they haven’t peed much during the day and / or that their urine is darker in colour. This happens because when you’re dehydrated your kidneys try to reabsorb as much water as they can and so the urine becomes more concentrated.

Another confusing factor that I’ve certainly noticed is that I will feel really hungry and want to eat However, when I think about it the reality is that I know I’m dehydrated and getting some fluid in solves the issue.  Whilst this might seem like an odd confusion to make, there are multiple studies that demonstrate we often confuse the cues to eat and drink and in one such study people got it wrong 3 times out of 5.

The hotter the weather the more fluid you need. I conducted an experiment on myself when I was training for the Jogle. I would weigh myself before a run and then again when I finished. I was surprised to find that I was regularly about 1Kg lighter on my return. Fluid is not just lost through sweat but also through the moisture in exhaled breath and, in my case from nose and eyes running due to irritation by wind or pollen.

What I found more startling though was that when the temperature rose above 22 degrees Celsius, my weight dropped by almost 2 Kg for the same length of run.

Tomorrow we’ll talk about rehydration.

Never let others put limits on what you can achieve