According to the WHO, 85 decibels can be tolerated for up to 8 hours, but at 100 decibels, a common level in nightclubs or with headphones turned way up, the safe limit drops to 15 minutes. Damage to the inner ear is permanent. The organization estimates that over a billion young people risk hearing loss because of their listening habits. Turning the volume down and taking breaks helps protect your ears.
Chlorine on its own is fairly gentle. But when it combines with urine, sweat and other grime from swimmers, it forms chloramines, which cause stinging eyes and that classic 'chlorine smell'. A well-kept pool barely smells at all. Shower before you swim and never pee in the water.
Muscle mass slowly shrinks with age, putting independence at risk. But in 1990, a study had nursing home residents aged 86 to 96 train their legs for eight weeks: their strength more than doubled. Muscle responds to training at any age. Getting up from a chair without using your hands is already an exercise.