Exposure to infrared heat promotes the expansion of capillaries. This naturally improves blood circulation. At the same time, under the influence of infra red heat on the body, the blood supply to the muscles also improves. This provides faster wound healing and reduced muscle pain. Our heaters not only bring tremendous health benefits but can be used indoors and also outdoors due to being IP67 rated. Please see the following youtube video of our heater being fully submerged this proves how rigorous our testing is and we are confident you will find peace of mind when buying our heaters.