As important as warming up or the actual workout, cooling down is equally important. ACE Fitness. Your blood flow will be maintained by cooling down after a workout. This will prevent injuries, soreness, lactic acid buildup, endorphin release, and reduce soreness. Even a 10-minute cooling down period after your workout can prove to be harmful to your health.
After your last rep, your body will have a faster heart rate, a higher temperature, and dilated blood vessels (via the American Heart Association). If you stop exercising, or don’t give your body enough time to cool off, you might feel unwell, or even faint. You may feel lightheaded or lose consciousness if your heart rate and blood pressure drop too fast. By gradually cooling down your body — slowing down your heart rate, lowering your body’s temperature, and regaining mental focus after physical activity — you’ll put yourself at less risk post-workout.
Your cooldown exercise doesn’t have to be complicated; stretching will usually suffice. You’ll feel ready to go as normal after your heart rate drops below 120 beats per hour.