HOME
Exercise Doesn't Eliminate Obesity Death Risks
Increased physical activity does not eliminate the potentially deadly health risks associated with obesity, US study findings suggest, just as being lean does not counteract the risks connected to low fitness levels.
The researchers, led by Dr Frank Hu from the Harvard School of Public Health in Boston, Massachusetts, say that their findings fail to support the theory that, "if you are fat but physically fit you do not have to worry about your weight because physical activity can cancel out the risk associated with obesity."
They analysed data from a study of more than 116,000 women aged between 30 and 55 years who were free from cardiovascular disease and cancer when the study started in 1976.
During the 24-year follow-up period, 10,282 women died - 2370 from cardiovascular disease, 5223 from cancer and 2689 from other causes.
After analysing information on the body mass index (BMI) and physical activity level of each participant, the researchers found that while higher levels of physical activity had a slightly beneficial effect on longevity, this did not eliminate the high risk of death associated with obesity, defined as a BMI of 30 or above (a BMI of between 25 and 29 is classed as overweight).
Indeed, compared with active, lean women who had a BMI lower than 25, women who did a similar amount of exercise but who were obese had almost twice the risk of death. Similarly, women who were lean but inactive had a 1.5-fold increased risk of death.
However, people who were both inactive and obese fared the worst, with a 2.5-times higher risk of dying compared with physically active, lean women.
Estimating that a BMI of 25 or higher and physical inactivity "could account for 31% of all premature deaths among non-smoking American women," the researchers conclude that "public health campaigns should emphasize both the maintenance of a healthy weight and regular physical activity."
N Engl J Med 2004; 351: 2694-2703
Last updated 18 January 2005
Related Articles
