Hydration has become a hot topic this week with the heatwave covering most of Europe, and for good reason. Staying hydrated is extremely important for our health and for our performance when participating in sport and exercise.
In this blog I’m going first going to explain why staying hydrated is so important, when dehydration levels start to become a problem and how we can tell. Then we’ll take a look at skiing, how dehydration effects skiers and the best way to keep your turns looking and feeling sharp all day long.
Why is hydration so important?
As I’m sure you were probably told in a school biology lesson, our bodies are made up of around 70% water. The water in our bodies is important for various processes and functions including maintaining core temperature, transport of nutrients, removing waste products and balancing pH level¹.
With that in mind it’s not hard to understand why we suffer when we are dehydrated. It’s generally considered that once dehydration goes beyond 2% (that’s once you have lost 2% of your normal hydrated bodyweight in water, so a loss of 1.4kg for a 70kg person) your exercise performance will decrease². There are even some studies showing that performance loss starts even before the 2% threshold.
Studies show that when someone becomes dehydrated during exercise, they experience a variety of physiological changes. Heart rate, core temperature and rate of perceived exertion (how hard they think they’re working) all go up, while their blood volume, stroke volume (volume oxygenated blood pumped out of the heart to the body in one beat), cardiac output (volume of blood pumped out of the heart in one minute) and skin blood flow (blood flowing near skin surface to reduce body temperature) all go down².
This combination of factors reduces athletic performance as necessary nutrients and energy sources are not delivered to the muscles as efficiently.
How do you know when you’re dehydrated?
It’s easy to tell once you’re already dehydrated – you’ll feel thirsty, get headaches, have a dry mouth and you might feel tired or lethargic³.
By this stage your exercise, or skiing, performance will already be suffering. So we need know before we get to that stage.
We can do that by predicting how much water we’re likely to lose during exercise, i.e. how much we’re going to sweat. How much we sweat depends on a variety of factors including the environment (temperature, breeze, humidity), our clothing, the intensity of the exercise and how sweaty of a person we are. This can vary from losing 300ml/hour of sweat up to 3000ml/hour of sweat².
You can estimate your own sweat rate by weighing yourself before and after you exercise and using the calculation below:
(Pre-exercise weight (g) – Post-Exercise weight (g)) + Drink Volume in ml = Sweat Lost in exercise (ml)
(Sweat Lost in exercise (ml) / Duration of exercise (mins)) x 60 = Sweat Loss Rate (ml/h)
You can then work out how much water you should be drinking per hour of exercise to replace the sweat you lose. If you can’t be bothered to work it out exactly then a rough guide is 1L/hour of exercise, which should keep most adults from crossing the 2% dehydration threshold². This water can be mixed with salts, electrolytes and carbohydrates as well if you are exercising for long periods of time – while salt loss won’t affect your performance, maintaining your intake will encourage you to drink more, helping to stay hydrated².
How to stay hydrated while skiing?
Well, studies have shown that the most effective way of staying hydrated while you ski is to wear a backpack hydration system (BPHS). In experiments with both ski instructors and with recreational skiers involving participants performing 2 days of skiing, one with a BPHS and one without and hydrating only at lunch breaks, it was shown that when the participants wore the BPHS they ended the day in a hydrated state while on the ski days without the BPHS they ended the day dehydrated⁴’⁵.
However, if you’re like me and you don’t like wearing a backpack while you’re skiing on piste, what can you do instead?
1. Find out all the places on the mountain where water is available – usually restaurants and bars, picnic rooms, lift stations and toilets.
2. Plan your day so that you pass one of these places every few runs so you can get a quick drink, try to drink a whole glass of water (around 250ml) each time you stop.
3. Pre-hydrate at breakfast – as well as your tea or coffee try to drink a good amount of water before you leave to go skiing – aim for between 500ml and 1L. More if you had a big Aprés the day before.
4. Hydrate at lunch. Before you get on the booze try to drink a few glasses of water first and continue to drink throughout the meal.
5. Post-ski hydrate. Make sure you drink plenty throughout the evening – water as well as wine!
Happy hydrating!
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