NIH researchers had volunteers learn a typing sequence, alternating 10 seconds of practice with 10 seconds of rest. The surprise: most of the improvement happened during the breaks, not the practice. A follow-up study showed the brain replays the sequence at high speed while resting. Instrument, sport or keyboard: build in brief pauses.
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.