Heat Slows You Down. Even When It’s Not Real
In a 2012 study, for example, the negative effects of cycling in 89-degree heat were partly erased when the thermometer in the room was rigged to read 79 degrees. And several recent studies have explored using things like menthol that create a perception of coolness to enhance performance in the heat. The heat pad was turned up to about 104 degrees, just a few degrees above normal body temperature.
Source: www.outsideonline.com