What is meant by cardiovascular fitness?
There are lots of different terms used to describe exercise for your heart. You might have heard of cardiovascular exercise, cardio or aerobic exercise to name a few.
Simply put, these terms can be broken down into:
- cardiac – relating to your heart
- vascular – relating to the system of blood vessels that carry oxygen around your body
- aerobic – meaning your muscles ‘use oxygen’ to carry out the movement
When you do cardiovascular or aerobic exercise, you’ll notice that your breathing gets heavier and your heart rate goes up. This is so that your lungs can take in more oxygen, and your heart can deliver this oxygen to your muscles for movement.
It’s worth noting though, that when it comes to your overall fitness, it’s not just the health of your heart that counts. In fact, how well your heart, lungs, blood and muscles use oxygen when you exercise all have a role to play. One way to test your overall fitness is using a VO2Max test. This measures the maximum amount of oxygen your body can use during exercise.
How much cardiovascular exercise should you do?
In the UK, it’s recommended that every week, adults do at least:
- 150 minutes (2 ½ hours) of moderate intensity activity (such as brisk walking or cycling)
- or 75 minutes of vigorous intensity activity (such as running)
- or even shorter durations of very vigorous intensity activity (such as sprinting or stair climbing)
- or a combination of these
Generally speaking, doing any exercise at all is better than doing none, and even doing short amounts of very vigorous exercise may be beneficial for your health.
There are lots of different exercises that will get your heart, muscles and lungs working. Some examples could include swimming, running, cycling, circuits, brisk walking, football, tennis, rugby, dancing and boxing.
How can exercise help to look after your heart?
Keeping active can help you to maintain a healthy weight and reduce your risk of developing type 2 diabetes – both of which are essential when looking after your heart health. And over time as you continue to exercise, your heart adapts to become stronger and more efficient at pumping blood around your body. Here I’ll explain some of the mechanisms behind this.
Grow your heart muscle
Some conditions, like heart disease and high blood pressure, can cause your heart muscle to thicken, and the strength of it’s contraction (pumping mechanism) to weaken, which can be harmful to your health.
But when you train your heart through exercise, just like any other muscle, it’s cells (called myocytes) multiply and grow in shape and size. When your heart muscle grows in this way, it has a more powerful contraction. This is sometimes referred to as ‘athlete’s heart’.
Increase your stroke volume
Your heart has four chambers, two on the right and two on the left. The left side of your heart has to work harder to pump blood to your whole body. But, the right side only has to pump blood to your lungs. As your heart muscle grows from exercising, the size and shape of your hearts chambers also increase. This means they can hold more blood and each time your heart contracts (pumps), it can eject more blood around your body (known as stroke volume). Having a higher stroke volume also means your heart is more efficient, as it can deliver more oxygen to your muscles during exercise.
Lower your resting heart rate
Your resting heart rate is the number of times your heart beats every minute when you’re at rest. People who are physically fitter, often have a lower resting heart rate than those who don’t exercise. This is because exercise causes your heart to become stronger and more efficient at pumping blood around your body with each beat. So, it doesn’t have to work as hard to distribute blood around your body. This is in comparison to someone who’s heart has to beat faster every minute to do the same amount of work.
Lower your blood pressure
When you exercise, it’s normal for your blood pressure to rise temporarily. This is because your heart and blood vessels work hard to deliver more oxygen to your muscles for movement. This increase in blood pressure usually returns to normal when you stop exercising.
But, if your blood pressure is continuously high, it can cause the left ventricle (chamber) of your heart to increase in size. While exercise can help to grow and strengthen your heart muscle, if your left ventricle becomes thicker as a result of high blood pressure, this could lead to heart disease.
Being physically active can also help keep your blood pressure healthy. This is because when you exercise, a gas called nitric oxide is released from the cells that line your blood vessels. Nitric oxide helps the muscle around your blood vessels to relax and open, which decreases your blood pressure. Over time, this can reduce the resistance of your blood vessels at rest, and lower your blood pressure.
Improve your cholesterol profile
Cholesterol is a type of fat found in every cell in your body. Although your body needs it to function properly, having too much of some types of cholesterol in your blood can increase your risk of heart disease and stroke.
There are different types of cholesterol, sometimes known as ‘good’ and ‘bad’ cholesterol. Together, they make up what’s known as your total cholesterol or lipid profile.
High-density lipoprotein (HDL) cholesterol is often called ‘good’ cholesterol, because it transports excess cholesterol to your liver to be removed from your body, which is good for your heart health. Non-HDL cholesterol on the other hand, refers to all the cholesterol in your blood that isn’t good. This includes low-density lipoproteins (LDL) and triglycerides (TAG). Having too much of these types of ‘bad’ cholesterol in your blood can lead to heart disease.
Studies have shown that regular exercise can help to improve your cholesterol profile and lower your risk of heart disease. It’s thought that this may be by increasing the size and levels of ‘good’ HDL cholesterol particles in your blood, whilst reducing the harmful non-HDL lipoproteins.
But studies vary on the effect that exercise has on different types of cholesterol. While exercise has been shown to have a positive impact on your overall cholesterol profile, it’s not clear yet just how much exercise, what type, or level of intensity you would need to do to see the best results.
What types of exercise are good for your heart health?
Ultimately, doing some exercise is better for your health than doing nothing at all. The important thing is to choose something you enjoy and get your body moving. But, when it comes to your heart, is any one type of exercise better at improving the efficiency of your heart than another?
The term endurance training is often used to describe exercise that is sustained or lasts for a long time. Although the amount of time exercising can range from minutes to hours, depending on the intensity of the exercise. An example could be running for 30 minutes, where your heart has to work harder for a longer period of time.
Endurance exercise has been shown to improve how well your muscles use oxygen. It also helps to slow your resting heart rate and increase the strength of your hearts contraction, which means it doesn’t have to work as hard when at rest.
High-intensity interval training (HIIT)
High-intensity interval training, or HIIT, is a method of training that’s gained lots of interest in recent years. It involves doing short burst of exercise as hard as you can, followed by a recovery period. For example, you might run on the spot as fast as you can for 30 seconds, then jog lightly for 30 seconds, and then repeat. HIIT training is great if you’re short on time, and can be applied to lots of different exercises. It can also be adapted to suit your own level of fitness.
Just like endurance training, HIIT has been shown to improve your cardiovascular fitness. But, it’s important to remember that cardiovascular fitness doesn’t just involve your heart. How well your lungs and muscles use oxygen during exercise play a part too.
It’s thought that the improvements to your overall cardiovascular fitness from HIIT training, may be because HIIT training significantly improves your muscle’s ability to use oxygen during exercise (your VO2Max), rather than just how your heart functions.
In addition, some studies have shown that high intensity interval training may be better at reducing body fat than moderate intensity exercise. This could help to you to maintain a healthy weight, reducing your risk of heart disease.
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