OK, so what's this got to do with kendo? Plenty. As the northern hemisphere swelters through a hot summer you'll be needing a good way to rehydrate. Here it will be our turn soon enough!
At the Kitamoto Summer School for Kendo it's nothing for some people to lose up to 7 kg of their body weight in the course of a day's training. As 1 litre of water weighs 1 kg, that's 7 litres if water coming out as sweat!
Of course water is good for rehydration, and 麦茶 (mugi-cha or cold barley tea) is great, but both do pass through your system quite quickly. Isotonic sports drinks have been shown to re-hydrate the body more effectively through the addition of electrolytes. The theory, as far as I understand it, is that the addition of these electrolytes (i.e. salts) encourages the body to retain a higher percentage of fluids. In other words you don't go to the toilet as much!
Years ago I heard a story that athletes at the 2004 Olympics in Athens were responding to the extreme heat and shortage of sports drinks by emptying sachets of salt into their water bottles. Whenever I buy a sports drink I always feel ripped off at how little 'content' there is. Basically water, sugar and salt. And for that you pay a premium for the privilege of adding another plastic bottle into the recyclosphere.
Recently I was bed-ridden with a bad case of gastro. My wife bought me some bottles of sports drink and I had time to read the label. This New Zealand-made brand was thoughtful enough to list all of them in detail (Australian labelling laws allow for the use of substitute code-numbers). From that, and some trial and error of my own, I came up with this recipe. Fine tune it to your own taste and save a fortune!
Ben's isotonic wonder drink (makes 750ml)
2-4 heaped teaspoons of sugar
3 drops apple cider vinegar
EDIT: the tip of a teaspoon of salt
1 tbs lemon juice (or lime, orange, mandarin, etc, or any combination)
hot and cold water
Dissolve the dry ingredients in 1/2 cup hot water. Then add vinegar and lemon juice. You can experiment with honey instead of sugar if you prefer. Add remaining cold water. Voila!
You know you have right amount of salt if there is an extra taste of something but not actual saltiness. Basically it tastes like a sports drink.
As you can see there is indeed very little 'content'. It's 99.something% water. The electrolytes are just sodium chloride, a.k.a. salt. The secret ingredient is the vinegar. The right amount helps to combine the taste of the salt and the sugar, making them palatable without the vinegar being noticeable itself.
This drink contains everything the commercial drinks contain:
- carbohydrates (sugar),
- electrolytes (salt),
- antioxidants, Vitamin C (a.k.a. lemon juice)
* (Yes, they're just lemons really).