Obesity means having excess fat in the body. There are various causes for being obese but it is the wrong dietary habits and a sedentary lifestyle that are mostly responsible for being fat.
Being obese puts you at a high risk to a host of complications that span all your body systems. The most dangerous ones are the effects on the cardiovascular system, which include heart disease and stroke.
According to the World Heart Federation, 21 percent of chronic heart disease is attributable to overweight and obesity (BMI above 21).
Among the middle-aged women who are overweight, cardiovascular disease begins 1.8 years earlier and 4.3 years in obese women as compared to women of normal weight.
Obesity has been classified as a disease and has attained epidemic proportions worldwide. It affects almost all countries making the increasing global obese population prone to coronary heart disease.
Obesity, waist size, and heart disease risk
Obesity and heart disease often coexist because, in an obese person, you often find elevated cholesterol levels, atherosclerosis, type 2 diabetes, and high blood pressure. These are some of the common health complications caused by obesity.
These are also risk factors that can independently precipitate a heart attack in a person. Together they make the overweight and obese person (BMI>25) very prone to cardiovascular disease at an early age. The higher the BMI more is the risk.
Overweight and obese people are at a higher risk of developing heart disease than people with normal BMI. Studies also confirm that obese people have a shorter lifespan than people with a healthy BMI.
When we talk of obesity and its risks, we talk of central obesity where the fat is deposited more around the abdomen and not the peripheral obesity where the fat is deposited around the hips and the thighs.
It is the central obesity where you carry more weight around the waist and chest that increases your cardiovascular risk.
BMI indirectly measures body fat and does not tell you whether the obesity is central or peripheral.
Waist size, therefore, is important to determine the risk. According to the Heart Foundation, a waist circumference of more than 94 cm (37 in) in men and 80 cm (31.5 in) in women tells you of excess fat deposits around the body organs such as the heart, kidneys, liver, digestive organs, and pancreas.
This significantly increases the risk of heart disease and stroke. Waist circumference and BMI are measurements that help to access the risk.
Waist circumference is taken into account under normal conditions and not when the abdomen is distended due to pregnancy or due to ascites or some such other conditions.
Effect of obesity on heart rate
A normal heart rate or pulse rate is 60 to 100 /minute. In an obese person, the body has excess fat and more mass.
The heart has to pump more blood to reach the excess body area. Since the blood pumped out per heartbeat is the same, the heart can meet the extra demand only by increasing its heart rate.
That is why the heart rate is faster in an obese person.
Over time, as atherosclerosis develops in an obese person, blood supply reduces further and this can lead to ischemic heart diseases such as angina and myocardial infarction (heart attack).
Atherosclerosis is ten times more prevalent among obese people than in people of normal weight making them that much more prone to a heart attack. Obesity and heart attack are frequent companions.
How obesity increases the risk of heart failure
In obese people, due to the excess body mass, the heart requires to put in extra effort to pump blood to various parts of the body. Further, due to high blood pressure in obese people, the heart has to pump against the additional pressure in the arteries.
This constant extra pressure on the heart causes the heart muscles to hypertrophy, which can lead to ventricular hypertrophy of the left side and later on, of the right side of the heart.
Left ventricular dysfunction leads to right ventricular dysfunction. Progressive cardiac dysfunction can lead to congestive cardiac failure.
Heart failure is seen more in patients with severe obesity. Its risk in overweight people or those with mild obesity is not so common.
And, the longer period you are obese, higher is the risk
According to a study quoted in The New England Journal of Medicine, for each increment of one in BMI, the risk of heart failure increases by 5 percent in men and 7 percent in women.
As compared to people with healthy BMI, obese subjects doubled their risk of heart failure.
How obesity increases the risk of heart attack
An increased BMI tends to promote the formation of fatty deposits in the arteries (atherosclerosis) and predisposes the person to heart attack due to complications such as hypertension, diabetes, and dyslipidemia.
However, even without these comorbidities, obesity alone is recognized as an independent risk factor in the development of heart attack.
According to a study conducted by the University of Glasgow, middle-aged obese men have a 60% greater chance of developing a heart attack even if we cancel out the existence of hypertension, diabetes, and dyslipidemia. In addition, obesity-related heart attacks tend to be fatal.