Regular exercise is an important part of maintaining health, improving quality of life and preventing disease. Guidelines for physical activity are great for saying how much exercise you should do and at what intensity. But what’s commonly left out is the importance of warming up and cooling down, and how you should do that. The warm-up and cool-down are the bread to your exercise sandwich.
The Benefits of a Warm-Up and Cool-Down
Our bodies are no different from any other machine. They work well when warmed up. But suffer when starting cold. Going out for a run, bike ride or playing tennis without warming up is like getting in your car, starting it and flooring the gas right away. At best case, without a warm-up, your performance can suffer. At worst case, you can strain or tear a muscle, or even succumb to a heart attack.
On the other hand, a sufficient warm-up can prevent injuries. It can also help you mentally prepare for the workout ahead. And some research suggests it can reduce muscle soreness in the days following your exercise session. Likewise, a cool-down is key to a controlled slow down, and can prevent dizziness and even fainting.
Exercise Physiology and the Warm-Up
When we start exercising, our muscles increase their demand for oxygen so carbohydrates (sugars) and fats can be used for energy. To accommodate this increased need, our body undergoes a number of changes to ensure oxygen-carrying blood gets to our working muscles.
The most obvious changes include increases in breathing and heart rates. Our lungs extract the oxygen from the air, and our heart pumps it into our body. But these aren’t the only changes. Just as important is the expansion of our arteries (dilation) to allow for an increase in blood flow.
While our heart is pretty quick to increase it’s beating, the response of the arteries to dilate takes longer. This is in part because it’s the rush of blood flowing through the arteries that acts as the signal. Inside the artery walls are receptors that sense changes in blood flow. As blood rushes by, the arteries increase in diameter.
At the same time, the working muscles are ramping up their energy producing pathways. These pathways are geared toward producing ATP. ATP is the only molecule muscles can use to power their contractions. Each muscle has a small amount of stored ATP, enough for about 8-10 seconds of work. Any exercise beyond that requires ATP to be created from sugars and fats.
Fat provides the best bang as it has more calories per gram than sugar. However, it takes several minutes for muscles to get the fat-burning pathway going. The use of sugars begins earlier but still not right away. So those first few minutes of warming up are needed to turn on your sugar and fat-burning pathways so you can keep on exercising.
In addition to firing up your energy pathways, a warm-up increases the temperature of your muscles. This occurs primarily as a result of the increased blood flow. The increase in muscle temperature can lead to improved muscle contractility.
The Often Forgotten Cool-Down
Considered the poor cousin of the warm-up, a cool-down shouldn’t be forgotten. While cooling down doesn’t appear to affect your risk for injury, it can prevent blood from pooling in your legs and reduce your chances of fainting.
When you stop exercising, your heart rate begins to decrease immediately. However, the response of your arteries to go back to normal size (constrict) is slower. This results in a fall in blood pressure, making it harder for the blood to return back to the heart.
If you’re standing up, gravity will cause the blood to pool in your legs. When that happens, less blood goes to your brain and you feel dizzy. If it continues, it may lead to fainting.
The risk for dizziness is more common if you’re doing upright exercise on your feet, such as running, and suddenly stop. But it can even happen after you finish swimming or rowing (or any exercise not on your feet) if you finish and stand up right away. This is similar to the feeling when getting up from the couch too quickly.
An active cool down, such as walking around, prevents this. When you walk (jog, or run), the contractions in your calf muscle act as a one-way pump to push your blood back to your heart. Standing still doesn’t work as your calf muscles aren’t contracting. That’s why it’s common to see soldiers faint or take a knee when on parade and standing motionless. Even though they haven’t been exercising, gravity will still cause blood to pool in their legs.
Some Key Tips to Remember
- Your warm-up should consist of activities using muscles you plan to use in your workout. Most the time it’s easiest to warm-up in the activity you plan to do, for example, brisk walking before running. But if that isn’t possible, warm-up with movements similar to that of your chosen activity.
- Your cool-down should also be active, but it’s not as crucial to your performance since the exercise has already been completed. Stretching can be part of your cool-down but it shouldn’t replace the active part of your cool-down.
- Aim for 5-10 minutes for your warm-up and cool-down. But listen to your body. In cold weather, you may need to allow more time to warm-up and you may want to cool-down inside.
- As we age, both the warm-up and cool-down become even more important. Everything is slower to reach peak efficiency. In particular, it takes longer for the arteries to dilate and constrict.
- In people with heart disease, missing a warm-up or doing a short one may result in angina or chest pain. This is the result of the heart arteries not been given enough time to open to allow sufficient blood flow to the heart. If this happens, a longer warm-up is needed (if it persists, consult your doctor).
Doing a proper warm-up and cool-down will help ensure your exercise routine is able to keep you healthy and injury free for many years to come.
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