If used at high temperatures, infrared sauna blankets can induce heat stress, which causes the release of heat shock proteins and a temporary rise in cortisol levels. That’s a normal part of the body’s stress response and it supports your immune system. The temporary rise in cortisol levels is nothing to be concerned about, and they’ll likely drop back to baseline levels as you cool off and relax. In fact, studies have shown that regular sauna bathing can help your body to better regulate its cortisol levels.