Bones get denser when they absorb impact and carry body weight. Swimming and cycling are great for the heart, but supported by water or a saddle, they do little for the skeleton. Walking, running, jumping, stairs and strength training work far better against osteoporosis. Swimmers and cyclists should mix things up.
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.