A recent study by the ACE (American Centre for Exercise) looked into the differences seen between a regular and a hot yoga class and found no difference in core temperature or heart rate between the two. Sweat loss will be more when exercising in the heat giving the feeling that you’re working harder, yet unfortunately sweat rate doesn't always equal exertion rate.
There are some benefits however - it’s been shown that exercising in heat increases blood flow and may increase cardiovascular capacity and muscle flexibility. It may also give you the feeling of ‘cleansing and detoxing’ - although in practice you don’t eliminate toxins by sweating them out - you simply get rid of water and salts. Either way, it’s important to remember that whether you’re sweating through exercise in the heat or in a normal temperature, staying hydrated is essential and rehydrating effectively after any exercise session will help you to recover safely and quickly.
Written by Ruth Tongue