Ease out of your workout just as you eased into it during a warm-up — by walking, jogging, or cycling lightly. If you’ve been using a stair-climber at Level 5 for 20 minutes, you could cool down by dropping to Level 4 for a couple minutes, then to Level 3, and so on.
The cooldown should last five to ten minutes — longer if you’ve done an especially hard workout.
The purpose of the cooldown is the reverse of the warm-up. At this point, your heart is jumping, and blood is pumping furiously through your muscles. You want your body to redirect the blood flow back to normal before you rush back to the office. You also want your body temperature to decrease before you hop into a hot or cold shower; otherwise, you risk fainting. Cooling down prevents your blood from pooling in one place, such as your legs.
When you suddenly stop exercising, your blood can quickly collect, which can lead to dizziness, nausea, and fainting. If you’re really out of shape or at high risk for heart disease, skipping a cooldown can place undue stress on your heart.