Going by a random Reddit thread [1], it takes less than 5 calories to charge an iPhone. I think that kind of device is already on the market though. You're not

Going by a random Reddit thread [1], it takes less than 5 calories to charge an iPhone. I think that kind of device is already on the market though. You're not gonna power a heater or aircon through body movement, but devices should be fine. 1. https://www.reddit.com/r/theydidthemath/comments/693daq/comment/dh3ej37/ https://www.reddit.com/r/theydidthemath/comments/693daq/comm...