How much exercise do you actually need for health?
The major guidelines converge closely, and the figures are lower than many people assume — while the biggest benefit comes from a step most people overlook.
The UK Chief Medical Officers' and WHO guidance for adults:
150 minutes of moderate intensity activity per week, or 75 minutes of vigorous, or an equivalent combination.
Strength activities on at least two days a week, working all major muscle groups.
Reduce sedentary time, breaking up long periods of sitting.
Older adults additionally need balance and coordination work at least twice weekly, to reduce falls risk.
What the intensities mean practically. Moderate means you can talk but not sing — brisk walking, cycling, doubles tennis, heavy housework. Vigorous means you cannot say more than a few words — running, swimming lengths, singles tennis, a spin class.
Three things the guidelines emphasise that get lost:
The largest single gain is from doing something rather than nothing. The dose-response curve is steepest at the bottom — moving from sedentary to modestly active produces a far greater reduction in mortality risk than moving from active to very active. Someone doing nothing gains most from a daily walk.
Strength training is genuinely part of it, not optional. It is the most commonly skipped half of the guidance, and it matters increasingly with age for muscle mass, bone density and independence.
Every minute counts. Previous guidance required bouts of at least ten minutes; that requirement was removed because evidence showed shorter bursts count too. Stairs, a brisk walk to a shop, and carrying shopping all contribute.
On the 10,000 steps figure: it originated in 1960s Japanese pedometer marketing, not research. Studies since have found substantial mortality benefit at considerably lower counts, with benefits levelling off well before 10,000 in older adults.
More has additional benefit up to a point, with diminishing returns.
Any activity you will sustain beats an optimal plan you will not.