Don’t exceed your endurance limit while exercising

LATELY, there have been a number of deaths of young or middle-aged individuals who succumbed during (or immediately after) a workout in a gym. The recent ones include actors Siddhaanth Surryavanshi, Puneeth Rajkumar and Sidharth Shukla. Such instances keep surfacing periodically and when they claim the life of a celebrity, especially a fitness enthusiast, they attract media attention and create a scare in the public mind.

People take up physical exercise either to lose weight, remain fit and prevent diseases or to build up endurance for sports and bodybuilding. How do these apparently irreconcilable views reconcile: regular physical activity may protect one from heart disease, yet exercise itself may cause sudden death? And the question in everybody’s mind is: can one predict it and what is the optimal level of exercise?

Generally, the underlying mechanism of sudden cardiac death during or after exercise is the disparity between the supply and demand of oxygen by the heart. It can be due to asymptomatic atherosclerotic coronary artery disease, heart muscle diseases like cardiomyopathies (hypertrophic and arrhythmogenic) and conduction defects, among other causes.

There are two main types of exercise – aerobic and anaerobic. Aerobic exercise (also known as cardio or cardiorespiratory exercise) uses oxygen and involves repeating sequences of light-to-moderate intensity activities for extended periods of time, like walking, cycling, swimming and jogging and games like tennis and basketball. Aerobic exercises can help strengthen the heart, build stamina, lower cholesterol and blood pressure and reduce risk of diabetes.

Anaerobic exercise involves short bursts of fast and high-intensity workouts like weightlifting, calisthenics and short-distance running, which don’t make use of oxygen like aerobic activities. It uses the energy that is already stored in one’s muscles. Exercise against resistance such as weightlifting also helps improve bone mass and density, making the bones stronger.

The simplest exercise is walking. Walking not only leads to weight loss and improvement in physical well-being, but walking 2,000 to 10,000 steps per day is also associated with a 10 per cent lower cardiovascular event rate. Besides, an additional 2,000 steps per day is associated with a 25 per cent reduction in the incidence of elevation in blood sugar. Overall, if one changes from a sedentary lifestyle to walking 10,000 steps a day, one is close to halving the risk of death in the ensuing decade.

Public health experts recommend 150 minutes of moderate physical activity per week for all ages along with two to three sessions of resistance training. During moderate-intensity exercise, you can keep up a conversation during the activity. If you can speak three or four sentences in a row without gasping for air, it’s a sign that you’re maintaining an intensity that is truly aerobic.

Your heart rate should be roughly 50-70 per cent of your maximum heart rate (220 minus your age). For a 50-year old, the maximum heart rate would be 170; and for moderate exercise, the upper limit of the heart rate during exercise would be 120. For high-intensity aerobic exercise, the target heart rate is up to 70-85 per cent of your maximum heart rate. At this intensity, you will likely be able to say a couple of words before needing to gasp for air.

A study in the US had found that 16 per cent of the sudden cardiac arrests in the Seattle area had occurred in exercise facilities, with over half of them surviving the event in a supervised exercise facility (well-equipped gym), but only one-third surviving if the event occurred in a public place like a mall. A gym should have certified staff and cardiac resuscitation equipment, such as an automated defibrillator. Both these are a far cry in our country.

In any case, it is incumbent upon the fitness enthusiasts to undergo a medical examination before resorting to strenuous exercise. To prevent mishaps during physical activity, persons above 40 years of age should ideally have a cardiac screening before initiating vigorous exercises.

Sportspersons aiming for professional sports are also advised to have a cardiac check-up. Any family history of heart disease should be brought to the doctor’s notice. The six-pack aspirants are the ones who need to be careful in setting their targets and planning their schedules.

Many a time, there are early warning symptoms, like breathlessness, palpitation, chest discomfort or fatigue which should not be ignored. It is important to plan one’s exercise schedule under expert guidance and not exceed one’s endurance limit. When trying to lose weight, it’s important to create a calorie deficit by consuming fewer calories than one normally does or by exercising more. The best way is to combine the two, eating a little less while being more physically active. On an average, a calorie deficit of 500 calories each day for a week will reduce weight by approximately half a kilogram. Depending upon the individual’s weight, walking for an hour at 5 km/hour burns 200-350 calories. More vigorous exercise burns more calories.

One can reduce calorie intake by cutting on calories in simple carbohydrates, like sugars, and fats. Per gram of each, fats have more than double the calories (9/gram) of carbohydrates and proteins (4/gram each). A high-protein diet makes the body do more work to generate energy for bodily functions and it burns fat and builds muscle. Today, a number of digital and mobile apps are available which can help one keep track of the calories consumed and spent. The “calories in, calories out” concept of weight loss seems simple, but many factors contribute to weight loss or gain, including hormonal changes, genetics, and age.

Many fitness enthusiasts use protein and nutritional supplements for weight loss or muscle-building. Many weight-loss supplements contain sibutramine, a drug that increases the risk of cardiovascular events. Some muscle-building supplements contain anabolic steroids which have been linked to multiple organ failure and myocardial infarction in young athletes. It is possible to fulfil most of the nutritional requirements of moderate-to-high physical activity without resorting to supplements.

Thus, while exercise is needed to remain healthy and lose or maintain weight, to avoid an untoward event during exercise, one must start gradually, know and remain within the limits and be aware of one’s own body.