Cardiovascular disease is one of the leading causes of death globally. The proportion of deaths attributed to cardiovascular diseases has been rising, with an estimated 20.5 million deaths in 2021. There is a worrisome trend of increasing heart attacks or arrhythmias in the younger population.
A large cohort of medical community believes that being physically active helps manage weight, keeps the blood pressure under control, reduces the risk of heart disease and stroke, diabetes, and metabolic syndrome, lowers the risk of cancers, strengthens bones and muscles, delays the onset of dementia, improves confidence and creativity, boosts energy, and helps reduce stress. On the other hand, vigorous physical activity can acutely or gradually increase the risk of acute myocardial infarction and sudden cardiac death in vulnerable individuals who exceed their physiological limits.
One of the most practical ways of calculating the body's energy expenditure (calorie consumption) is with metabolic equivalents (METs). One MET is the rate of energy expenditure while sitting at rest. Energy spent during physical activities is expressed in multiples of resting metabolic rate . The desired exercise intensity is graded as follows by American College of Sports Medicine (ACSM):
-Light: An intensity that evokes slight increases in heart rate and breathing (2-2.9 METs), like walking at a slow pace (2 mph or less), light household chores.
-Moderate: An intensity that evokes noticeable increases in heart rate and breathing (3-5.9 METs), like brisk walking (2.5 -4 mph), golf, table tennis, tennis doubles.
-Vigorous: An intensity that evokes substantial increases in heart rate and breathing (≥6 METs), like jogging, running, shoveling snow, singles tennis, soccer, swimming.
Even intensities lower than 6 METs may still create stress on cardiovascular system in unfit and sedentary individuals.
Sudden strenuous high intensity, high volume exercise in an apparently healthy but unaccustomed individual or someone with cardiovascular risk factors such as (diabetes, hypertension, smoking, obesity, family history of heart disease, dyslipidemia, physical inactivity, renal dysfunction) or with pre-existing occult heart disease can be hazardous. The possible triggering mechanisms include: supply-demand mismatch by increasing the myocardial workload, thus reducing the blood flow (ischemia), plaque rupture in atherosclerotic arteries and thrombotic occlusions leading to heart attacks, increased wall stress from increase in heart rate and blood pressure, acute type A aortic dissections, exercise induced coronary artery spasm in diseased arteries. In addition to ischemia, sodium-potassium shifts during exercise, catecholamine rises and circulating free fatty acids may increase the risk of abnormalities of heart rhythm (arrhythmias) that can be fatal. All these can lead to unexpected death. Overall sudden cardiac death (SCD) during exercise is a rare event occurring between 0.31 and 2.1 times per 100,000 people per year. Autopsy studies revealed a range of abnormalities, from ischemic cardiomyopathy to hypertrophic cardiomyopathy or congenital coronary anomalies. However, sudden arrhythmic death or SCD with structurally normal heart (SNH) could be the common cause of death in young individuals according to the recent studies.
In recent times, there has been an alarming rise in exercise-related deaths. The foremost thing is to understand the triggering factors that contribute to sudden cardiovascular events. Never ignore any symptoms of chest pain, fatigue, difficulty in breathing, dizziness, nausea, jaw pain, palpitations, left or right sided shoulder pain or back pain during exercise. Exercise must be stopped immediately, and medical help should be sought. Continuous long-duration strenuous exercises without breaks or relaxation can be hazardous. Never over-exert and strain your heart. The health risks of vigorous physical activity certainly exceed the benefits for those who have just started exercising without awareness of their fitness level. Dehydration and electrolyte imbalance in an intense workout can be detrimental to cardiac health and predispose to arrhythmias. Hence, balanced nutrition is essential.
Many observational studies reveal that the best defense against exercise related cardiovascular events is to maintain physical fitness by doing regular moderate intensity aerobic exercises combined with resistance training. Injudicious use of supplements such as “Performance-Enhancing Substances”, can have serious health consequences.
American Heart Association (AHA) recommends that adults get at least 150 minutes per week of moderate intensity aerobic activity or 75 minutes per week of vigorous aerobic activity (or a combination of both), preferably spread throughout the week. Adults should also do muscle strengthening activities (like resistance or weight training) of moderate to greater intensity that involves all major muscle groups on at least two days per week. American College of Sports Medicine (ACSM) have designed a new algorithm focused on four major variables: (1) current level of individual’s physical activity (2) known cardiovascular metabolic or renal disease (3) signs or symptoms of cardiovascular disease (4) desired or anticipated exercise intensity (light, moderate, vigorous). These, along with vigorous physical activity in an unaccustomed individual were identified as an important cause of exercise-related acute cardiovascular events.
Some essential strategies to reduce the cardiovascular events would include the following: pre- participation screening, excluding high risk patients from certain activities; evaluating, and reporting the prodromal symptoms; preparing fitness facilities and trainers for cardiovascular emergencies; and recommending structured, monitored, progressive exercise programs. One must have knowledge of their cardiovascular risk factors and must undergo pre-entry investigation before enrolling safely into a structured fitness program. Although 100% risk cannot be assessed. The AHA recommends that participants in fitness facilities be screened with the specially designed pre-participation screening questionnaire to identify the individuals at risk who should then be medically evaluated. The exercise facility must have an automated external defibrillator (AED) as well as CPR trained personnel to manage acute cardiac arrest emergencies. The bottom line is to make exercise: safe, enjoyable and regular.
“Dose dependent mindful exercise along with balanced nutrition is the mantra for optimal cardiovascular health”.
Dr.Monica Kher
