When visitors to the Energia Gym in Hadley, Mass., put their feet on the pedals of the Spin bikes, they are reducing their carbon footprint at the same time.
That's because the bikes in Energia's studio have been retrofitted so that they can turn the energy of the workout into electricity.
An average one-hour workout can create enough energy to power two laptops. Over the course of a year, the gym estimates it will produce enough power to light 72 homes for a month, while reducing the amount of carbon dioxide by 5,000 pounds.