By Paul Taylor

My local gym is a gleaming, shining mecca for health and fitness, an all-hours joint with a tight cluster of machines, free weights and daunting TRX straps. The staff are militant about cleanliness, so I know I’m not going to suck in the stink of the 100-odd people who have been there in the 24 hours before me.

Puddles o’ perspiration

Sweat’s the prime reason your gym’s going to reek, especially if it’s full of big burly blokes who practise poor hygiene and stand around between sets dripping body fluid onto the floor and equipment. Mopping up a sopping pool from the benches isn’t just good manners for the next person. If the top material on a bench is stitched together on the sides or near where your head rests, there’s a good chance that sweat will nestle in the seams, and that’s prime ground for bacteria. Kudos to the gyms with antibacterial wipes for you to clean up after yourself.

Grubby digits

Look around. Without getting too CSI and busting out the UV light, think about what’s had grotty fingers all over it – touchscreens on treadmills, bikes, ellipticals and so on should see the foamy end of the bottle of screen cleaner if the staff and the cleaners are on top of things. Over time, the spray won’t make them look pretty (for the same reason you shouldn’t clean your iPhone with the same stuff you clean your bathroom mirror with – it’s too harsh), but it’s better than seeing everyone’s fingerprints and imagining where they’ve been.

Stinky emissions

Sweat’s not your gym’s only problem. Some protein powders can have, er, unfortunate side effects, like causing excess gas. If you’ve just started taking a powder, think about all the other people in your gym doing the exact same thing, and the pressure on their guts when they’re busting out a deep squat.

Alongside air-conditioners and giant fans that circulate air, good gyms will also have air pumps installed rather than relying on an open window. Having air blowing around is one thing but it’s no good if it’s a heady mix of sweat, farts and exhaled CO2, and even the pumps in smaller places can circulate 300 litres of fresh and old air in and out per minute. Consider this: the average, untrained male will have a VO2 max (the amount of oxygen you breathe over time) of 35-40ml per kg of body weight per minute, and females 27-31ml per kg per minute (meaning an 80kg bloke will breathe in and out roughly 3 litres of air per minute, and a 60kg female 1.8 litres per minute). When you get really good, like elite-runner good, you’ll be churning over roughly double that amount – that’s a lot of old air that needs to go somewhere.

So, if the person next to you is doing their best Steve Moneghetti on the treadmill, readying a shaker full of Ultra Bulk but horrifically missing a towel, there’s a reason you’re left wrinkling your nose.