Does more exercise mean greater benefits to the heart?

Rueseggeret and Booth in their 2018 paper listed that exercise helps in preventing at least 40 conditions which are worsened by physical inactivity, ranging from diabetes, hypertension, depression, anxiety, obesity, osteoarthritis, and breast, colon and other cancers. In a 2016 paper in the journal ‘Cardiology,’ Steven Lewis and Charles Henneken argued that exercise is the new-age ‘Magische Kugel’ or the ‘Magic Bullet’, an epithet given by Nobel laureate Paul Ehrlich for medicinal pills. The life expectancy at the age of 50 is seven to eight years higher in those who exercise in comparison to those who do not.

Yet, more is not always better in exercise. The large exercise volumes and vigorous intensity physical training — specially when performed by unfit individuals, or erstwhile physically inactive people — have the potential of accelerated coronary artery calcification, myocardial fibrosis and atrial fibrillation, which can precipitate as acute myocardial infarction and of sudden cardiac death.

People get surprised that some regular gym goers and physically fit people also develop cardiac health issues. The answer lies in the fact that exercise can reduce the modifiable risk factors, but cardiac outcomes are also dependent upon non-modifiable factors such as genetic make-up of an individual and the family history. Exercise reduces the risk of adverse cardiac outcomes but it is not a guarantee.

What are the different types of exercise? There are two main groups of aerobic or endurance, resistance or strengthening. In addition, balancing and flexibility are two more types of exercise. To get maximum benefit, an individual needs to have a blend of these in their routine.

The exercises which increase one’s heart rate and breathing (such as brisk walking, swimming, cycling, jogging or dancing) are termed as aerobic or endurance exercise. These can and should be done by all adults. In addition to reducing body weight, aerobic exercise helps in relaxing blood vessels and lowering blood pressure; helps in burning calories, lowering blood sugar levels and reducing body fat. Cardio reduces inflammation and raises levels of good cholesterol. Understandably, aerobic exercises reduce the risk of heart disease, Type 2 diabetes and nearly three dozen health risks.

Another key type of exercise is strengthening or resistance. This is needed as with increasing age, there is loss of muscle mass. Therefore, strengthening exercise helps rebuild muscle mass and stimulates bone growth, in addition to other benefits.

So, what is the beneficial level of exercise? For healthy adults between 18 and 65 years, at least 30 minutes of “moderate intensity aerobic activity” in a day, and at least 150 minutes in a week is recommended. There should not be more than two days of break in between. For those with risk factors such as diabetes and hypertension, the recommended duration should be 60 minutes and 300 minutes per day and week, respectively. Those above 65 years should be involved in some exercise three or more times in a week. The strengthening exercise can be done alternate days or two to three times a week.

In India, one in every 10 adults is diabetic and one in five has hypertension, though half of them are unaware of them being diabetic or hypertensive. Indians have the unique characteristic of appearing slim but having a high body fat content which puts them at high risk for heart and liver diseases. The rising epidemic of being overweight and obesity is another challenge. In this backdrop, nearly all adults should be engaged in a combination of aerobic, resistance, flexibility and balance exercise beyond their routine physical activity. The exercise should be done to meet the ability and requirement of an individual. A majority of healthy adults can start with moderate intensity physical activity with no need to consult a physician before starting. However, those with pre-existing coronary artery disease, diabetes or other risk factors or those who have been physically inactive for long must consult a physician before getting involved in moderate and high intensity physical training.

Dr Lahariya is a consultant physician with specialist training in the management of diabetes, hypertension and acute coronary syndrome.