A healthy body will self-regulate its temperature even in the hottest of climates, but consideration must be given to the function of the VTi. The VTi can be impacted by extreme heat if exposed for a prolonged period because it is reactive to temperature. If a VTi turns red and you are in a hot climate, firstly seek shade and hydrate. If you have not got a high temperature the VTi will revert to its original colour and this will indicate that reaction has been caused by exposure to extreme sunlight. The VTi has not yet been tested in extreme climates.