Wonder of wonders — it’s actually hot and sunny in London! This unaccustomed blessing means that you need to pay extra attention to hydration when practicing hot yoga. The amount of water and electrolytes you need is going to increase as you sweat more outside of the studio, even if you don’t feel thirsty. Coconut water is the best source of electrolytes so stock up!

There is a useful article on Mind Body Green about proper hydration and replenishment for hot yogis. I’ve quoted a couple of key points below and you can click the link for the full article.
coconut water

How can you tell if a student is not properly hydrated in class?

When a student is having a hard time in general, this can be a sign of dehydration and/or loss of electrolytes. Signs are: tiredness, dizziness, they’re not sweating enough, and /or their muscles are cramping.

What would you recommend to a hot yoga student in terms of replenishment if they are only hydrating with water during a summer practice?

If you’re practicing hot yoga, like the Bikram series, you cannot properly hydrate with just water, especially in the summer.

Electrolytes are charged molecules (positive or negative) that become active in water. They conduct electricity in the body and are instrumental for transmitting signals. They regulate, among other things: muscle contraction, heart rate, balance of body fluid, and pH levels. They affect all organs and systems in the body.

The body needs the right balance of water AND electrolytes for communication signals to be sent throughout the body. For example, if you are depleted in sodium or potassium, the signal from the nervous system cannot reach the muscle cell. This results in muscle cramping.

What should we include in our food diet to help along hydration?

Foods high in water: fruit and veggies, especially. Avoid caffeine (try decaf!), alcohol, and starches as they are dehydrating.