Two great challenges facing western society are the looming energy crisis and the alarming increase in obesity. But if technology has developed to a point where we can efficiently trap kinetic energy, then could green gyms become little power stations burning human energy and sequentially running it into the grid?

As more health clubs install energy-producing exercise equipment it’s becoming a prospect that burns ever more brightly. The Club and Spa at Cadbury House, just south of Bristol, is one of Britain’s largest independent gyms with 4,000 members. It was the first health club in the world to install the Artis Renew range of sustainable exercise machines. Designed by the Italian company Technogym, they comprise bikes, resistance machines and cross trainers. For Tom Horton, operations manager at Cadbury House, this is a glimpse of a future that includes sustainable gyms powered by their users.

The average output of a hour’s cycling is 100 watt-hours. Such a quantity of energy could power items such as a clock radio, a toaster or a laptop. Photograph: Atlantic

The Edge, the fitness, sport and wellbeing complex at Leeds University, is another to have installed the machines. Last month it congratulated members for generating a cumulative 574KWH of power, saving “an impressive 258kg of CO2”. It announced that such a saving was enough to power a plasma TV for 158 days, light a room for 9,573 hours and keep a fridge running for nearly two whole years. In America, Portland’s Green Microgym is using 85% less electricity with help from Technogym’s equipment, reducing its carbon footprint to about a tenth of a traditionally run gym per square metre.

Granted this output isn’t going make coal shareholders break sweat, but if we look at the increase of efficiency of electronics across the board it does have some merit. Take the evolution of the light bulb: LED bulbs are now six to seven times more energy efficient than conventional incandescent lights, and have cut energy use by more than 80%.



All this begs the question, with appliances becoming much more energy efficient, are we on the verge of a new sustainable future-powered by the humble treadly?

A cyclist shows how much energy can be produced from pedal power.

For Philip Mawby, professor of electrical and electronic stream at the University of Warwick, the idea might be “a gimmick but it is a very interesting gimmick”. Mawby explains that the chief problem is output. “If you were a Tour de France cyclist, you could probably get up to around 800W on an exercise bike. But for a typical person this is a lot less – someone pretty fit would be about half this. When you scale that up, you’re going to have to do a lot of pedalling to create anything sizeable.”

So in terms of resolving the deficit in Britain’s energy reserves, green gyms’ impact would be minimal. Yet Mawby says the idea isn’t without merit. Gyms do gather a critical mass of people together and it would be quite possible, he says, for a gym to power its in-house LED lighting completely by harvesting the energy from its Artis machines. “You might be able to charge everyone’s phones too,” Mawby suggests.

Mawby points out that Panasonic has recently launched a home battery system that allows people to store “enough energy for the household for several hours”. This energy could come from a variety of sources, he reasons, like solar panels as well as hooked up bicycles.



A human-powered flywheel, designed by Indian engineering professor JP Modak. Photograph: encyclopediapictura

“It’s more cost-effective to store the energy yourself rather than put it back into the grid, so storing energy isn’t such a strange idea. In the future we will see more of these batteries.”

Professor Mawby feels that experiments like that at Cadbury House have a primary benefit is that they are making people aware. Through active engagement members are forced to acknowledge the physical value of energy and the cost of expanse of its wastage.

Horton agrees, the members have engaged so well with the machines he thinks that it has changed attitudes in the health club. “People realise what it is to power a light bulb or a fan and we do too,” he says. “The machines have really brought environmental issues on the radar for us,” he adds. “Because of them we have started to look into more efficient lighting, and we’ve got in touch with an energy specialist who is now advising us. I really think this is the future.”

Anyone who’s experienced the drudgery and torture of a standard gym visitation knows that you don’t reward your punished abdomen with a post-workout slice of mud cake. Why? Because they know how much time, cost, sweat and self-motivation is required to burn energy/fat. Similarly, those using green equipment know that a light burning for 15 minutes is equal to a 20km-plus bike ride.

It’s not about how much energy a human can make, it’s more about how much a human can save. And like fitness, for sustainability to have any real impact it needs to start with the individual and requires ongoing commitment before there is any real change. So while energy power station gyms may not produce blinding light, their existence does leave a little more light at the end of the tunnel.



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