Why, despite cases of sudden cardiac deaths, exercise is still an important activity for health.

I have read about marathon runners dying suddenly due to heart attack. Is exercise really safe?

What you read about is called sudden cardiac death. This is death occurring during or after exercise. It is usually due to coronary heart disease if it occurs among those above 35 years old. Among people below 35, the most common cause is cardiomyopathy.

Sudden cardiac death mostly occurs in older male athletes. Often, it is preceded by signs and symptoms which are sometimes ignored. The risk is greater in marathon compared to half marathon.

About five per cent of total sudden death is associated with exertion or exercise. Exercise can trigger a heart attack and, at the same time, confer heart health benefits. This is what we call the exercise paradox.

High-intensity exercise transiently increases the risk of heart attack and sudden cardiac death. Those who do high intensity exercise have a higher risk of getting sudden cardiac death, compared to those who do moderate intensity exercise.

A study among 10.9 million runners in the United States was published in the New England Journal of Medicine in 2012.

The study showed that the incidence of cardiac arrest is one in 184,000 runners and incidence of sudden cardiac death is one in 256,000 runners. The incidence is extremely low.

A study done in 1993, published in the same journal, showed that the risk of getting heart attack during high-intensity exercise is twice compared to at rest.

However, the study also showed that a physically inactive individual has 50 times more risk of getting heart attack than his physically active counterpart. Many studies showed that a physically active person has 50 per cent lower risk of getting heart disease.

This means the relative risk of getting heart attack and sudden cardiac death during high intensity exercise is higher than at rest but the absolute risk of getting this is very low.

Looking at the benefits of exercise on heart and the risks, it is clear that the net benefit outweighs the risk, even though you engage in high intensity exercise such as jogging or running.

To conclude, the incidence of heart attack and sudden cardiac death in exercise is extremely low and exercise is safe for everybody.


If you are not sure of your health status, see a doctor for medical examination. In some situations you may need further test such as an exercise stress test, if indicated. Photo from www.thesun.co.uk.

Why do people die during a marathon and how can we avoid it?

It is extremely rare for a healthy person to get a heart attack during exercise, including high-intensity exercise.

However, some people may have occult heart disease that goes undetected. Most of the sudden deaths that occur during or after exercise is due to atherosclerotic coronary artery disease. Autopsy findings showed that they mostly had ruptured plaque.

The risk of sudden death during exercise is higher in a person with underlying heart disease and is unaccustomed to high-intensity exercise.

It usually occurs towards the end of exercise or after completion. There is also a possibility of electrolyte imbalance and dehydration that may cause the problem. Increase in intensity towards the end may also contribute to the condition.

To ensure you exercise safely:

1. Make sure you are healthy before you exercise.

2. Avoid and control other risk factors such as smoking and a bad diet.

3. If you are not sure of your health status, see a doctor for medical examination. In some situations you may need further test such as an exercise stress test, if indicated.

4. Do regular health screening to detect disease, preferably yearly.

5. Watch for any symptoms of heart disease and see a doctor if present.

6. Do not ignore any symptoms of heart disease.

7. Progress gradually. Start with lower intensity and gradually increase frequency, duration and later intensity over weeks or months until you reach your target.

8. Exercise at low to moderate intensity. No high-intensity exercise (i.e more than 75 per cent of maximum heart rate) if you are not sure of your health status.

You can also do a simple assessment on your own by answering simple seven questions in Physical Activity Readiness Questionnaire (PAR-Q). The current version is PAR-Q+ and is available at http://eparmedx.com/. It is better than the older version. See a doctor if you answer “Yes” to any of the questions.


Sudden cardiac death mostly occurs in older male athletes. Often, it is preceded by signs and symptoms which are sometimes ignored. Photo credit: www.newstalk.com

What are the symptoms and signs we need to observe to avoid sudden cardiac arrest?

Most sudden cardiac arrests or sudden cardiac deaths during exercise have no warning signs and symptoms. However, if you have any of these symptoms, do not ignore them and see a doctor for further investigation.

1. Near fainting or fainting, especially during exercise or during recovery.

2. Chest pain or discomfort or tightness at rest or with exercise. The chest pain and discomfort may be radiated to neck, jaw, shoulder, arm, abdomen and back. It may be associated with sweating, nausea and vomiting.

3. Unusual or excessive shortness of breath during exercise.

4. Fast or irregular heartbeat or heartbeat skipping with no apparent reason.

5. Dizziness or lightheadedness, especially with exercise.

6. Unusual fatigue or weakness with exercise or sometimes, a dramatic drop in performance.

7. Family history of sudden cardiac arrest prior to the age of 50.

If you have any of the above symptoms while exercising, stop immediately. Call for help and seek medical advice.


See a doctor if you have chest pain or discomfort or tightness at rest or with exercise. Photo from manzap.com

An avid sportsman who believes in the healing power of exercise, Assoc Prof Dr Ahmad Taufik Jamil is Universiti Teknologi Mara’s public health consultant and exercise physician. Email him at atjamil@gmail.com

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