GET NAKED

We generally use a rule of thumb when it comes to hydration, about 500ml an hour. But for some, it could be up to a litre or way more depending on environmental factors, speed body weight etc

If you want to get your hydration a bit more dialled in you can do your own sweat test

𝗦𝗼 𝘄𝗵𝗮𝘁 𝘁𝗼 𝗱𝗼…

1. Get Naked

2. Weigh yourself in kg’s

3. Take note of the temperature and wind

Run easy for 60 minutes, if you take a drink that’s fine you just need to know how much exactly so we can take off.

If you pee we can assume it’s 2-300ml

4. Now it’s time to strip back off.

5. Dry yourself with a towel

6. Write down the difference In weight

Let’s say you lost 1kg and drank 300ml so the total is 1.3l right

A gram of water is 1ml so a kg loss is 1000ml.

Most people can handle around 1l of water an hour and not put too much strain on the kidneys…. 𝗕𝘂𝘁 𝘆𝗼𝘂 𝗱𝗼𝗻’𝘁 𝘄𝗮𝗻𝘁 𝘁𝗼 𝗿𝗲𝗽𝗹𝗮𝗰𝗲 % 𝗼𝗳 𝘄𝗵𝗮𝘁’𝘀 𝗹𝗼𝘀𝘁

The sweat rate losses range from 0.5-2.5l an hour with the average around a litre.

But we know that it’s not all from sweat loss as the body holds around 500g of glycogen and for every g of glycogen you hold onto 1-3G of water so this is an estimate but 100% better than just winging it completely.

We want to replace 50-80% of that fluid loss and top end of 1L. I use the rule of thumb to aim for 500ml an hour.

We don’t want to replace 100% or accidentally more as you can cause Hyponatremia, which is a medical term describing low blood sodium levels.

There are a few different causes of the condition, but the one of interest to athletes is when dilution of sodium levels in the blood is driven by excessive drinking.

This can be exacerbated by the loss of sodium in sweat during prolonged exercise. This variant of the condition is known as Exercise Associated Hyponatremia or EAH.

So sodium plays an integral role in your body from muscle and nerve function to temperature regulation and most importantly fluid balance to name a few.

Hyponatremia can cause nausea and vomiting, headaches, confusion, muscle weakness, cramps and spasms and far worse.

This is generally only experienced in events of 9 hours or more so won’t happen to a general recreational runner but you can experience symptoms in shorter events due to a lack of electrolytes.

The average sodium loss is around 1000mg per litre lost. About replacing this there are several ways from tablets, drinks and food. You can start with 200mg for example and work anywhere up to 1000mg per L consumed.

You want to perform these tests in different conditions like temperatures and speeds etc.

I achieve this with a carb/electrolyte drink tailwind or Mountain Fuel, a sodium tablet ( 600mg ) with every 1l consumed and from food.