When sitting for long periods of time, the body doesn't "shut down," but its functioning changes noticeably. Leg muscles are barely involved in movement, energy expenditure remains low, blood flow to the lower extremities decreases, and after eating, the body is, on average, less able to cope with the rise in glucose and insulin than when sitting is periodically interrupted by short walks or other activities.
A short walk after a meal is beneficial primarily because working muscles begin to more actively utilize the glucose released into the bloodstream from food. As a result, the post-meal rise in blood sugar and insulin is usually less pronounced than if you sit or lie down immediately.
For most adults, achieving 150-300 minutes of moderate-intensity aerobic physical activity, 75-150 minutes of vigorous-intensity aerobic physical activity, or a combination of both is recommended per week for significant health benefits.
After age 50, there's no need to choose between walking and strength training: a combination of both is optimal for health. Walking primarily helps you build the necessary aerobic activity, maintain cardiovascular endurance, and spend less time sitting.
For most adults, a reasonable goal is about 7,000 steps per day. This isn't a new mandatory medical norm or a threshold below which walking "doesn't count." The benefits begin much earlier: if a sedentary person starts walking more than usual, their risk of adverse outcomes already decreases.
After age 60, most people should aim for 150-300 minutes of moderate-intensity aerobic activity per week, rather than the mandatory 10,000 steps. If walking is the primary activity, this could be, for example, about 30 minutes of brisk walking five days a week.
