As a general rule, you can determine your maximum heart rate by subtracting your age from 220. For example, if you are 50 years of age, your maximum heart rate during exercise would be 170.
However, what if you regularly exercise with a heart rate beyond this number and still feel physically fine? Is this safe?
"Heart rate tolerance is specific to the individual and better determined by experience," says Dr Stanley Chia, cardiologist at Mount Elizabeth Hospital, Singapore.
The 220 rule is a rough guide for training, but, as Dr Chia explains, there is a wide variation in how people respond to physical stress. Some may have no issues attaining higher heart rates during exercise, while others are unable to reach their formula-derived number.
You are perhaps your best judge as to what you can and can't do and how far you can push yourself while exercising. As a guide, don't exercise beyond a point where you have difficulty speaking or start to feel pain.
"If you find that your heart rate starts to climb while performing the exercise workload," cautions Dr Chia, "or if your effort tolerance becomes poorer, you should consult your physician."
Doctors can perform a test with the goal of pushing the exercise load, before symptoms like chest discomfort, shortness of breath or fatigue begin to set in. During this exercise, the heart rate may go beyond the maximum heart rate determined by the 220 rule.
You should seek medical attention if symptoms of chest discomfort, shortness of breath, dizziness or palpitations (irregular heart beat) are experienced during exercise. However, also be aware that not all patients will show symptoms. Some may have 'silent heart disease' that can only be detected through medical imaging examinations like electrocardiograms, echocardiograms or computed tomography (CT) scans.
Consult your doctor about maintaining regular blood pressure, doing blood glucose checks and screening for heart disease, particularly if you are advancing in age and have elevated cholesterol. Other factors like smoking and diabetes can also increase your risk for coronary artery disease.
Dr Chia concludes, "If you are concerned about your heart health, or experience any worrying symptoms, you should undergo some medical investigations before embarking on a more strenuous exercise regimen."