Exercise and heart disease


If you already have heart disease, can you exercise? Will exercise help prevent you from developing heart disease in the first place?

The answer is "yes" to both questions. Previously, people with established heart disease were told to "take it easy" and not stress their heart too much. The opposite is now true with cardiac rehabilitation programmes emphasising exercise as part of the lifestyle changes needed to improve cardiac functioning and prevent further damage. It is also an integral part of the treatment of people who have suffered heart attacks.

Why exercise for your heart?
Over the past decade or so there has been plenty of research showing that exercise can be an effective part of the treatment plan for someone with coronary artery disease.

There are two main reasons why people with heart disease should exercise:

  • to slow the course of the disease
  • to rehabilitate themselves by using exercise to restore normal or near normal function of the heart and the lungs

Exercise is important for people who do not have heart disease as well. Lack of exercise has been shown to be one of the main risk factors for developing heart disease.

How much exercise is needed?
The use of exercise to either prevent or treat heart disease is based on the idea that exercise will increase you ability to function – your functional capacity. This means that you'll find it easier to walk particular distances, climb stairs without becoming short of breath and enjoy activities such as gardening without becoming too tired. This will only happen with a regular training programme.

The recommended workload is a programme that provides exercise in the range of 70% to 80% of your maximum heart rate. This usually equates to an energy expenditure of around 300 kilocalories per session. The heart needs to be slightly overloaded since this will force it to adapt to a greater capacity. You should exercise to a level where you feel your exertion to be at least moderately hard, but you're still able to sustain this comfortably for around 30 to 40 minutes.

This is, of course, the baseline. For anyone with established heart disease, the programme must be worked out in conjunction with a doctor or cardiac rehabilitation centre.

But this is not to say that people with heart disease can only exercise at this level. Once the initial rehabilitation is done, there are plenty of people who have carried onto much higher intensity exercise and have become endurance runners or cyclists and continue training at a very high level.

What is safe exercise if you have a heart condition?
If you don’t have heart disease and simply want to keep fit, then any regular exercise programme that you enjoy and will stick to is fine (unless, of course, you have other health problems). But if you've recently had unusual shortness of breath or any chest pain, you should see your doctor before you start.

If you have a recognised heart condition, you must have a programme worked out for you by a professional exercise trainer in consultation with your doctor and you must use a heart-rate monitor while exercising. If you're recovering from a heart attack, you must only exercise within a recognised cardiac rehabilitation centre programme.

People who have heart disease should have a graded exercise stress test before starting any type of exercise programme. This allows an assessment of your ability to tolerate gradual increases in the intensity of exercise.

How do you know if what you're doing is safe?
Once you've started exercising regularly, you need to know when to stop. Be on the lookout for the following symptoms:

  • Pain or discomfort in your chest, stomach, back, neck, jaw or arms – never exercise to a point where you have pain in any of these areas. They can indicated lack of oxygen to your heart (ischaemia). If you feel pain in any of these areas, slow down or stop completely and tell your trainer.
  • Unaccustomed shortness of breath during exercise. If you suddenly find that you cannot do the same amount of exercise which was previously comfortable without becoming uncomfortably short of breath, then you need to see your doctor. If the change has appeared gradually over a period of weeks, then make an appointment to see your doctor within a week. If this is something you experience suddenly, see a doctor immediately.
  • If you feel dizzy or faint either immediately after or during exercise, then stop and lie flat on your back with your legs up on a chair. Arrange to see your doctor as soon as possible for a check up. It may simply be that you are overdoing it a bit and need to slow down.
  • If you feel nauseous during exercise, follow the same procedure as for dizziness.
  • An irregular pulse, when your pulse is usually regular during exercise, needs to be investigated. Tell your trainer and arrange to see your doctor.

Beta-blockers and calcium-channel blockers alter your heart rate. Make sure that your trainer knows which drugs you're on and continue to take them as usual when you start exercising.

What type of exercise should you be doing?
Aerobic exercise specifically trains the cardiovascular system. Activities such as walking, jogging, cycling, swimming, rowing, stair climbing, dancing and skipping are particularly good since they're continuous exercise and give you endurance capacity as well.

The type and intensity of exercise will vary depending on your level of fitness, motivation and capacity. You can work this out with your trainer.

Exercise should be something you enjoy, so that you'll stick to it. Don’t take up jogging if you hate it! You won’t keep it up and may become demotivated for any type of exercise at all.

You should maintain and improve flexibility, since this makes exercise more enjoyable and you're less likely to get injured. So warming up and stretching are important parts of any exercise programme.

Resistance training with weights was previously thought to be potentially dangerous in people with heart disease. Now we know that improving muscle strength and tone relieves strain on the heart, so this is an important part of exercise as well. However, don’t push big weights that will make you strain. Rather stick to light weights and increase your number of repetitions as you get fitter. Speak to your trainer about this.

A well worked-out exercise programme will have three elements:

  • aerobic exercise
  • stretching programmes
  • strength training

Always start at a comfortable level and increase the intensity gradually - usually over a period of six months. You should exercise for a minimum of 30 minutes three or four times a week.

Exercise should become part of your regular routine – enjoy it and get the best out of it!

- (The Heart and Stroke Foundation SA, Health24, updated December 2008)

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