But Dr Simon Mayhew sees gyms as accidents waiting to happen. A doctor who specialises in sports medicine, he sees a lot patients with substantial injuries from pushing themselves - and being pushed - too hard in the gym.
He deplores the rise of the "no pain, no gain" gym culture in which fit youngsters with dubious qualifications are put in charge of people whose medical history and, particularly, cardiac risk profile they have no idea about.
"You pay money and assume they have the right sort of qualification but there is no way that Joe Public can tell," he says. "People say they have 'a diploma in PT [personal training]'. I've no idea what [that] means, whether it is a weekend course or what. Clients go in and the gym says 'sign here - we'll get your weight down'."
Via Peter Mellow