After you run, you need to cool down gradually. This is absolutely critical to letting your body recover and setting yourself up to have a great run the next day.
A gradual cool down will return your heart rate and breathing patterns to normal and will help you avoid fainting and dizziness. If you stop instantly after a hard work out, blood tends to pool in your active muscles and doesn’t allow the blood in your working muscles to gradually get back to your organs such as your heart and brain.
Also cooling down will allow you to remove the waste products that have accumulated in your muscles during the run. Eliminating these waste byproducts from your blood prepares your muscles for the next exercise session. Cooling down will also reduce post-workout muscle soreness.
When cooling down, you need to gradually slow down your running pace over the last five to ten minutes. The harder you exercised, the longer the cool down should be. If you had an easy workout, you only need to slow down your running pace over the last five to ten minutes.
Stretching is also vital to cooling down as it allows you to get rid of any tightness that has developed during your run. Stretch all the major muscles in your body. You only have to stretch for about an additional ten minutes. If you are pressed for time, at least be sure to stretch your legs and back as they take the most beating during a run. When running, your legs are the most prone to injury and stretching will help prevent problems and restore your muscles to their resting length.