How to Check Your Heart Rate
Right after you stop exercising, take your pulse: Place the tips of your first two fingers lightly over one of the blood vessels on your neck, just to the left or right of your Adam's apple. Or try the pulse spot inside your wrist just below the base of your thumb.
Count your pulse for 10 seconds and multiply the number by 6.
Check your pulse periodically to see if you are exercising within your target zone. As you get in better shape, try exercising within the upper range of your target zone. (If just beginning an exercise program, consult your doctor first.)
Source: National Heart, Lung, and Blood Institute (NHLBI)