The study found that women who lived up to 90 years, on average, were taller and had less weight since the age of 20 compared to women who were shorter and heavier. There is no such relationship seen for men. However, men see more benefits from physical activity than women.
While this study is observational and cannot prove its cause, these findings "provide interesting clues that male and female health may respond differently to BMI, height and exercise," said epidemiologist David Carslake, a senior research fellow at the University of Bristol in England, who were not involved in this study. BMI, which stands for body mass index, is a measurement of body fat based on the calculation of height and weight.
In 1986, the researchers asked more than 7,000 Norwegian men and women between the ages of 55 and 69 about height, current weight, and weight at age 20. Both sexes also tell researchers about their current physical activity, including walking dogs, gardening, home improvement, walking or cycling to work and exercise. Men and women are then sorted into daily activity quotas: less than 30 minutes, 30 to 60 minutes, and 90 minutes or more.
Groups are monitored until they die or reach the age of 90; out of 7807 participants, 433 men and 994 women lived to that age. Problems that can affect longevity, current or past smoking and the level of alcohol use are also taken into account.
The men and women in this study fared very differently when it came to the effects of body size and exercise.
Women who weigh less at age 20 and gain weight when they are older are more likely to live longer than women who are heavier. Height plays a major factor: this study found women who were taller than 5 feet 9 inches were 31% more likely to live up to the 90s than women who were less than 5 feet 3 inches.
Both height and weight seem to be a factor in whether men reach their 90s, but the level of activity. Men who spend 90 minutes a day or more actively 39% are more likely to live up to 90 than men who are physically active for less than 30 minutes. In addition, for every 30 minutes a day active men, they are 5% more likely to reach that age.
However, women who are physically active for more than 60 minutes a day are only 21% more likely to live up to 90 than those who do 30 minutes or less. And unlike men, there are no bonuses for increasing activity. In fact, this study found that the optimal activity level for women is 60 minutes a day.
Slow life expectancy
"Now it's very clear that being overweight, obesity, and an inactive lifestyle are harmful to health," Carslake said. "Studies like this, which examine the form of associations, and ask whether they are the same in different groups … will be even more important."