A gym powered by sweat and tears

"A US gym has installed specially-adapted exercise bikes that recycle energy generated by people as they work out. The Green Microgym in Portland, Oregon, aims to be a carbon neutral exercise facility through the use of solar power and human-generated energy from clients as they pedal and run. "The big challenge has been finding the right equipment and adapting the technology," says Adam Boesel, the gym owner. The science behind generating electricity from gym equipment is not new. For decades people have been using dynamos on their bikes to power the front and rear lamps. Generating power in a gym setting is based on the same principle. "If you think about a gym, almost all of the exercise equipment has a spinning wheel, and if you can spin a wheel you can make electricity, just like a windmill makes electricity," explains Mr Boesel. The gym has teamed up with a Texas-based company, Henry Works, which is in the process of developing what it has dubbed the Human Dynamo." - BBC