“Thirst is a poor indicator of hydration; typically thirst indicates more than 2% loss of body fluids, and this corresponds to a 10% loss of exercise performance”
— Oxford handbook of Expedition and Wilderness Medicine
In this hot weather, people have been asking me about hydration on the mat. As a desert survival instructor, one of my main jobs was teaching people how to manage water well, especially in the heat. I also had to make sure no one got so dehydrated that it was a danger to themselves and others.
I reckon water is the most underrated performance enhancing substance on the planet. It’s cheap, legal in every country and hasn’t been banned by any sporting code.
Numerous medical studies demonstrate significantly impaired physical and cognitive function, even at minor levels of dehydration. It impacts memory, clarity of thought, problem solving, mathematical/ analytical ability, focus and fine motor skills. Some of these functions can deteriorate by up to 25% for 2% dehydration.
That’s a lot of stupid for the sake of a few glasses of water… Definitely won’t help in the 3D physical chess of BJJ!
Here are a few tips for staying properly hydrated before, during and after training:
➡How much is enough? – There is no set amount to drink. It depends on metabolism, diet, how hot it is, and how active you are – among other things. Ultimately, we have to replace every drop of fluid we lose or use in breathing, urinating, sweating and many other body functions. The easiest way to judge how much to drink is to refer to your urine colour and frequency. Wee should be copious and clear, or light straw coloured. Dark or smelly wee is an indicator you haven’t had enough to drink. This link has a chart to rate your wee. The most I have ever drunk was 21 litres in 24 hours, working outdoors in temps near 50 degrees. I was only just maintaining good hydration. Bear in mind that colour and smell can also be changed by supplements and illness, so if either of those are a factor it might not be so clear cut.
➡ Drink before and after training. – I find drinking lots on the mat makes me feel bloated and ‘sloshy’. In the 2 hours before training I make sure I am well hydrated. I drink extra if I need to, so I’m well loaded with water when I start. I have a decent drink after training, and keep going until I get a good clear wee. If you want an idea of how much sweat you’ve left on the mat, jump on the scales before you train and after. (Take your Gi off, because it will hold a lot of the water you sweated out). The weight difference will be mostly water. 1kg=1 litre. I’m sometimes 2kg lighter after training. It tells me I need to drink at least 2 litres to catch up.
➡ Monitor your wee. – A healthy person, properly hydrated, will urinate at least 4 and up to 10 times in a 24 hour period. If you typically don’t drink much water and decide to drink more, you may find you urinate a lot initially until your system settles down. That sometimes happens if you are playing catch up too. If you haven’t had a wee in the 2 hours before training, drink more.
➡ Drink, don’t sip – Lots of people only sip water especially when training . Sipping water does not prevent dehydration. In fact, it can make dehydration worse, because it masks thirst. Sipping satisfies your tongue, but none of the moisture gets to your organs or brain, where it is needed. Ideally, drink water a cupful (250 mL) at a time. Drinking this way gets enough fluid into your system to satisfy digestion and organs like liver, kidneys and lungs. Crucially it leaves enough left over to keep the brain properly hydrated. The brain is the first organ to suffer from dehydration, because the body will prioritise core survival functions over thinking if it has to.
➡ Mostly Water – Generally, fresh water is all you need. If you do get dehydrated sometimes it feels like plain water is not enough. Drinking can make you feel spewy, or it can just piss out the other end as quick as you put it in the top. At times like that, grab some electrolytes like Hydralyte or Gastrolyte. They are properly formulated to help your body absorb fluids. Sports drinks often have sugar and caffeine, which are not ideal. There are all sorts of other water additives that people chuck in their bottles. Many are sold as nutrition or recovery aids. As a general rule these won’t enhance hydration and may even work against it. If you want views on the benefits of supplements like these, there’s plenty of experience at the gym. Ask around.
➡ Overheating – If you feel like you are overheating, or getting faint, take some layers off, drink, or grab an icey from the fridge, stand in front of the cooler and sit out a round or two. The combination of overheating your core temperature (different from just feeling hot) and being dehydrated can lead to heat stroke which is very dangerous. Because of the brain function side of this, you may not always recognise it in yourself, so if your training partner is acting vague or spaced out, help them cool down and give them a drink. If you want more of this topic, Adam Connery has a heap of research based info from his work/experience as a firefighter. Have a yak to him – it’s fascinating stuff.
➡ After effects – if you feel very lethargic the day after training, you probably got dehydrated. This is different from usual training fatigue. You’ll lack energy, focus, motivation, maybe feel light headed or have a headache. This after effect can last for a couple of days. Good hydration helps you to maintain activity levels.
If you want more info, or specifics for your situation and training come and find me on the mat. Happy to talk about it in more detail.
A case study from the field.
Once, while filming a survival documentary with the BBC, I was tasked with sheep dogging a family of four as they walked through the Pilbara. Sheep dogging is following along behind a group to make sure the decisions they are making won’t get them into a dangerous situation.
It was a pretty warm day, in excess of 40 degrees Celsius, and the family were clearly not drinking enough to keep up with their hydration needs. As the day progressed, I could see they were getting clumsier, finding it harder to make decisions and leaving essential bits of kit behind. I had several conversations with them about water but they still weren’t drinking enough.
By mid-afternoon two of them were complaining of headaches and nausea. They were firmly of the belief that the river water was making them sick. I reminded them about dehydration and cognitive decline. One of the women replied that they were sharp as a tack and not dehydrated at all. I asked her what 2 × 8 equaled. She was literally unable to answer the question. The look on her face said it all. She knew the answer, but just couldn’t access it in her impaired state.
It was enough to get them all drinking again. If they had carried on without drinking, they would have eventually collapsed.
Dehydration to the point of collapse is entirely possible on the mat in very hot weather, especially if you are starting dehydrated.
Written by Mike House.
Learn more about Mike here: http://www.mikehouse.com.au/