The lactate produced during exercise clears in about an hour, long before soreness kicks in. Delayed soreness comes from tiny tears in muscle fibres and the inflammation that repairs them, peaking 24 to 72 hours later. It hits hardest after braking movements, like walking downhill. Good news: muscles adapt, so it eases the next time round.
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.