On a tech front, it's an interesting use of a peltier junction device. They are horribly inefficient yet really interesting. It is, effectively, a heat pump.

On a tech front, it's an interesting use of a peltier junction device. They are horribly inefficient yet really interesting. It is, effectively, a heat pump. It will make one side colder than the other. And that part is key. You must take away energy on the hot side or the entire thing will get hotter and hotter. Without heat removal on the hot side it would get hot enough to burn you very quickly. The article says they are using pulsed heat which might presumably deal with this issue. As others mentioned already, tricking the body like this could have negative consequences. I wonder if any studies exist on this (ice bags on the wrists or some such thing). It brought back memories of going sculling at the peak of winter. Due to the danger of falling into extremely cold water [0] I experimented with wearing a kayaker's dry suit. It worked reasonably well. A surprising find was that wearing a wool head-cap made me overheat. It was really amazing how quickly this would happen too. I can see this MIT gizmo having some effect because our skin is sensitive to heat flow, not absolute temperature. Not sure I'd like to trick my body that way though. What are the consequences of messing with the mechanism that maintains proper thermal balance? [0] There have been many incidents of rowers drowning in cold water within swimming distance of the shore. Swimming in cold water while wearing thin clothes and your heart pumping hard due to the physical exertion of rowing is extremely dangerous because hypothermic effects can be greatly accelerated. Even accomplished swimmers can drown fifty feet from shore.