every few minutes as you're running, to get a general idea of your rate throughout the session. You will probably find that, even if you maintain the same pace throughout, your heart rate will rise by 5-10 beats over a period of 30 minutes
with this by dilating capillaries close to the skin. This allows more blood to get close to the surface to help cooling. Your heart rate will often rise whether you're exercising or not. When you are running, the muscular work you're doing increases your body
