How Much Is Enough?

There are real numbers behind the general instruction to be more active, and they are more achievable than most people assume.

The target is at least 150 minutes of moderate activity a week — roughly 30 minutes on most days. Add strength training twice a week, and balance or stretching work two to three times a week.

The single most useful detail: it does not have to be done in one session. Activity broken into small amounts through the day counts towards the same total. Three ten-minute walks are not an inferior substitute for a thirty-minute walk; they are thirty minutes.

Moderate means you can talk but not sing comfortably. A brisk walk qualifies. So does cycling to the market, climbing stairs, and a good deal of ordinary household work.

The strength component is the part most people skip and it is worth keeping, because muscle is where a large share of glucose gets used. More muscle, used regularly, means more places for glucose to go — and it needs no gym.

One caution on the 150 minutes: if you are currently at zero, do not aim at it this week. Build up over a month instead.

And frequency beats intensity here. Because the insulin-sensitivity benefit fades within about a day, most days matters more than hard.