DO avoid Jacuzzis and hot tubs. They are a breeding ground for potentially dangerous bacteria. In tests of 43 water samples from whirlpool baths, all had some kind of microbial growth and, yuck, bacteria from faeces were present in 95% of samples.

DON'T wear the same pair of trainers two days running. Microbiologists found that sweaty running shoes have 76 times more fungi than a toilet bowl. According to the Society of Chiropodists and Podiatrists, it is best to have two pairs and allow one to dry out thoroughly before wearing again.

DO sit on a towel in the steam room or sauna. Wooden benches have lots of crevices in which bacteria colonise.

DON'T re-use your water bottle without sticking it on a full cycle in the dishwasher. A study at the University of Calgary reported high levels of bacteria in water drunk from plastic water bottles that were refilled without proper cleaning. Some of the water samples had significant levels of faecal bacteria, probably due to improper hand-washing by the owners.

DO wear flip-flops in the shower and changing rooms. Common diseases, such as athlete's foot and onychomycosis, another infectious fungal disease with symptoms including yellow, brittle toe and fingernails, lurk on the floors.

DO wipe down gym equipment before and after you use it, preferably with an antibacterial wipe. Sweaty residue on weights machines and exercise bikes could harbour streptococcal infections and even candida, the germ that causes yeast infection.