Cotton soaks up moisture, from sweat or rain alike, and dries slowly. And water draws heat away from the body up to 25 times faster than air, the US National Weather Service points out. A soaked cotton T-shirt becomes a radiator working in reverse. The CDC recommends an inner layer of wool, silk or synthetic fibre instead, then several loose layers and a wind-resistant, water-repellent outer layer.
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.