I often get asked why cooling down after exercise is advocated. In short, cooling down does the following:
1. prevents blood from pooling in your extremities. During exercise, blood is directed towards the working muscles. If you were to sot exercise right away, blood may pool in these muscles due to a rapid drop off in circulation. Syncope (think light-headedness) may result.
2. Metabolites and waste products accumulate in the muscles during heavy exercise. Light aerobic exercise during the cool down period may help promote circulation. This increased turnover of blood will help clear these waste products.
3. There are some claims that cooling down helps prevent muscle soreness, but the research is not clear. More on this later.
So how do you cool down? For starters, you can drop the intensity down to about 30-40% of your HRmax. The key is to gradually taper off the intensity of your workout. Stretching helps increase blood flow as well. Hold each stretch for about 30seconds.