Ordinary glass blocks most UVB, the rays behind sunburn, but lets through much of the UVA. Those rays penetrate deep into the skin, speed up aging and contribute to skin cancer. A famous 2012 medical photo shows a delivery driver after 28 years on the road: the side of his face next to the window had aged far more than the other.
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.