While many people perform a warm-up, cool-downs are usually ignored.  At the end of a workout, most people can't wait to finish, and so ignore their cool-down in the rush to the shower.
That's a mistake, because cool-downs serve several vital functions.  Most importantly, they will improve your performance and accelerate the recovery process before you train or compete again.
The benefits of a cool down include:
- Removing the body's waste products, especially lactic acid
 - Reducing the chances of DOMS ( Delayed Onset Muscle Soreness)
 - Reduce the chances of dizziness or fainting caused by blood pooling at the extremities
 - Reduce the level of adrenaline in the blood
 
So what exactly should you do at the end of your workout?  There are two parts to this process:
5 to 10 minutes of easy cardio - for example slowly jogging or walking.  This will allow your heart rate and body temperature to drop slowly, while still continuing to remove waste products from the muscles.
5 to 10 minutes of static stretching exercises.  This is the appropriate time to perform static stretches, as they help the muscles to relax while increasing their range of movement.