I have written previously about warming up before exercise. This frequently skipped part of a workout is important to increase blood flow to your heart and muscles as well as increasing your body temperature. A good warm up can also enhance your focus on the exercise session, which could improve your performance. Hopefully, you are spending 5-10 minutes doing a light-to-moderate activity like walking or jogging before you begin an exercise session.
You should also focus on what you do after exercise to cool down and recover. Cooling down after exercise is important for several reasons that can impact both safety and performance. This is the topic of my Health & Fitness column in the Aiken Standard this week.
An important reason for active cooldown is to prevent a condition called post-exercise hypotension, a drop in blood pressure that could lead to dizziness or fainting. When you exercise there is a huge increase in blood flow to your active muscles, bringing oxygen and nutrients as well as removing wastes. For most types of exercise, this involves blood being pumped down to your legs. This is aided by the blood vessels dilating, or getting wider, boosting blood flow.
The return of blood from your legs is enhanced by your contracting muscles pushing the blood back up towards your heart, a phenomenon called the skeletal muscle pump. If you suddenly stop exercising and stand still, the pumping action of the muscles is lost and blood can pool in your legs. This can lead to less blood flow up to your brain, resulting in lower blood pressure, dizziness, and fainting. This is most relevant for upright exercise like walking, running, cycling, or any exercise in which your head is above your heart, but it can also happen following resistance exercise, too.
Continuing to move at a lower speed after exercise can maintain the blood flow back to your heart and prevent this from happening. After a few minutes, the blood vessels return to their normal state and muscles activity is no longer needed to return blood to the heart. There are other physiological factors involved, and lower (but not too low) blood pressure may persist for several hours following exercise. This can occur in everyone, from young, healthy people to older adults with high blood pressure. In fact, this is part of the reason that exercise is effective for reducing blood pressure in people with hypertension.
A practical reason for active cool-down is that many people feel off-balance after hard exercise, especially on a treadmill. Most fitness center employees have seen clients suddenly stop a treadmill and step off, only to feel shaky and lose their balance. Walking at a slower speed before getting off a treadmill can help prevent this.
Active recovery is also important for performance in athletes, especially if they have back-to-back events. During intense exercise, muscles can accumulate wastes, including lactate, a by-product of energy production during intense exercise that can contribute to fatigue. These wastes are removed from the muscle after exercise, but research shows they are removed more quickly during an active cool-down period. Again, this is mostly relevant for athletes who need to recover quickly after a training session or event.
Given the benefits of cooling down after a workout, you should take the time for active recovery. At a minimum, a few minutes can help prevent a drop in blood pressure that could lead to dizziness or fainting. Your goal should be 5–10 minutes of less intense exercise to cool down. Together with a similar time for warming up, this will add time to your workouts, but the benefits will make that time well spent!