Ref: CHB/HB/034/15
OBESITY & IMPORTANCE OF EXERCISE
Obesity is a chronic condition defined by an excess amount of body fat. A certain amount of body fat is necessary for storing energy, heat insulation, shock absorption, and other functions.
Obesity is best defined by using the body mass index. The body mass index is calculated using a person’s height and weight. The body mass index (BMI) equals a person’s weight in kilograms (kg) divided by their height in meters (m) squared. Since BMI describes body weight relative to height, it is strongly correlated with total body fat content in adults. An adult who has a BMI of 25-29.9 is considered overweight, and an adult who has a BMI over 30 is considered obese.
How common is obesity?
Obesity has reached epidemic proportions in the United States. Over two-thirds of adults are overweight or obese, and one in three Americans is obese. The prevalence of obesity in children has increased markedly. Obesity has also been increasing rapidly throughout the world, and the incidence of obesity nearly doubled from 1991 to 1998.
What is the health risks associated with obesity?
Obesity is not just a cosmetic consideration; it is a dire dilemma directly harmful to one’s health. In the United States, roughly 112,000 deaths per year are directly related to obesity, and most of these deaths are in patients with a BMI over 30. For patients with a BMI over 40, life expectancy is reduced significantly. Obesity also increases the risk of developing a number of chronic diseases, including the following:
- Insulin resistance
- Type 2 (adult-onset) diabetes
- High blood pressure (hypertension)
- High cholesterol
- Stroke
- Heart attack
- Congestive heart failure
- Cancer
- Gallstones
- Gout
- Osteoarthritis
- Sleep apnea
What causes obesity?
The balance between calorie intake and energy expenditure determines a person’s weight. If a person eats more calories than he or she burns (metabolizes), the person gains weight (the body will store the excess energy as fat). If a person eats fewer calories than he or she metabolizes, he or she will lose weight. Therefore the most common causes of obesity are overeating and physical inactivity. Ultimately, body weight is the result of genetics, metabolism, environment, behavior, and culture.
What is the body mass index (BMI)?
The BMI uses a mathematical formula that accounts for both a person’s weight and height.
The BMI measurement, however, poses some of the same problems as the weight-for-height tables. Not everyone agrees on the cutoff points for “healthy” versus “unhealthy” BMI ranges.
BMI also does not provide information on a person’s percentage of body fat. However, like the weight-for-height table, BMI is a useful general guideline and is a good estimator of body fat for most adults 19 and 70 years of age. However, it may not be an accurate measurement of body fat for body builders, certain athletes, and pregnant women.
The World Health Organization uses a classification system using the BMI to define overweight and obesity.
- A BMI of 25 to 29.9 is defined as a “pre-obese.”
- A BMI of 30 to 34.99 is defined as “obese class I.”
- A BMI of 35 to 39.99 is defined as “obese class II.”
- A BMI of or greater than 40.00 is defined as “obese class III.”
What is the role of physical activity and exercise in obesity?
The National Health and Examination Survey (NHANES I) showed that people who engage in limited recreational activity were more likely to gain weight than more active people. Other studies have shown that people who engage in regular strenuous activity gain less weight than sedentary people.
Physical activity and exercise help burn calories. The amount of calories burned depends on the type, duration, and intensity of the activity. It also depends on the weight of the person. A 200-pound person will burn more calories running 1 mile than a 120-pound person, because the work of carrying those extra 80 pounds must be factored in.
But exercise as a treatment for obesity is most effective when combined with a diet and weight-loss program. Exercise alone without dietary changes will have a limited effect on weight because one has to exercise a lot to simply lose 1 pound.
Regular exercise is an important part of a healthy lifestyle to maintain a healthy weight for the long term. Another advantage of regular exercise as part of a weight-loss program is a greater loss of body fat versus lean muscle compared to those who diet alone.
Other benefits of exercise include
- Improved blood sugar control and increased insulin sensitivity (decreased insulin resistance),
- Reduced triglyceride levels and increased “good” HDL cholesterol levels,
- Lowered blood pressure,
- A reduction in abdominal fat,
- Reduced risk of heart disease,
- Release of endorphins that make people feel good.
General exercise recommendations
- Perform 20-30 minutes of moderate exercise five to seven days a week, preferably daily. Types of exercise include walking, stationary bicycling, walking or jogging on a treadmill, stair climbing machines, jogging, and swimming.
- Exercise can be broken up into smaller 10-minute sessions.
- Start slowly and progress gradually to avoid injury, excessive soreness, or fatigue. Over time, build up to 30 to 60 minutes of moderate to vigorous exercise every day.
- People are never too old to start exercising. Even frail, elderly individuals (70-90 years of age) can improve their strength and balance.
“Community’s health – CHB’s priority”