DALLAS, July 6 -- Elderly men who walked about two miles a day had half the risk of heart attack of males who walked a quarter mile, according to a study in today's Circulation: Journal of the American Heart Association.
The study of 2,678 men, whose ages ranged from 71 to 93, also found that the risk of a first heart attack dropped 15 percent for every additional half mile a day walked. The men, all of whom were enrolled in the Honolulu Heart Program (HHP) and were participants in a larger study of men of Japanese ancestry living on Oahu, walked from less than a quarter mile a day to eight miles daily.
Robert D. Abbott, Ph.D., professor of biostatistics at the University of Virginia School of Medicine, and one of the study?s authors, says the research suggests, "Encouraging the elderly to walk and to become active could have important health benefits. This is especially important because walking can be easily incorporated into a person's lifestyle and daily routine."
In an accompanying editorial, Peter G. Snell, Ph.D., assistant professor of internal medicine at the University of Texas Southwestern Medical Center in Dallas, and Jere H. Mitchell, M.D., chief of the cardiopulmonary division at the same institution, say that walking helps prevent heart disease by reducing the risk of atherosclerosis -- the buildup of fatty deposits that can clog heart arteries -- and of blood clots and irregular heartbeat, both of which can trigger a heart attack.
The study's findings may extend to younger men as well as women, according to Snell and Mitchell. They point to similar studies such as the Nurses' Health Study and the Harvard Alumni Study, both of which found that walking can reduce a person's risk of heart disease.
Snell and Mitchell remind older people to consult with a physician before beginning an exercise program. However, they add, "From a public health standpoint, the finding that exercise that is neither strenuous nor prolonged can benefit an individual at any age is encouraging. As personal computers invade our lives and society becomes increasingly successful at reducing our need to move, opportunities for everyone to become more physically active should be given a high priority."
Researchers ranked distance walked by the men in the study into three ranges:
less than
one-quarter mile a day; one-quarter to 1.5 miles a day; and more than 1.5 miles
a day.
The risk of heart attack in the two-to-four year study for those who walked less than a quarter mile a day was 5 percent compared to 2.5 percent of those who walked more than 1.5 miles a day. Men who had walked one-quarter to 1.5 miles per day had a 4.5 percent risk of developing heart disease compared to 2.5 percent for those who walked more.
A total of 109 of the men experienced a heart attack. Forty-one of them were among the 805 men who walked less than a quarter mile, 48 were among the 1,067 who walked a quarter to 1.5 miles, and 20 were among the 806 who walked more than a mile and a half.
All the men were physically capable of walking at least one hour at slight, moderate or heavy activity on a regular daily basis.
The study used data from medical records of 2,678 men ages 71 to 93 enrolled in the HHP, which has monitored more than 8,000 men of Japanese ancestry living in Oahu. Interviews conducted during examinations between 1991 and 1993 were used as a baseline. The men walked daily anywhere from a quarter-mile or less to as many as eight miles a day. Researchers kept track of each man's health status for two to four years after the exams.
Even after accounting for differences in other measures of physical function and cardiovascular risk factors, walking continued to be associated with a reduced risk of heart attack. But the researchers did not determine how many years the men had been walking, nor at what intensity they walked.
However, based on the responses given during the interviews, Abbott says it seems likely that walking was "an activity they've been involved in most of their lives."
Whether walking or regular physical activity in general could reduce an individual's risk of heart disease if begun later in life is not known, Abbott says. "However, research suggests that we should become active as early in life as possible. The earlier we start, the easier it is to continue those habits later on."
Co-authors are Amy A. Hakim, M.S.; David Curb, M.D.; Helen Petrovitch, M.D.; Beatriz L Rodriguez, M.D., Ph.D.; Katsuhiko Yano, M.D.; G. Webster Ross, M.D.; Lon R. White, M.D. and Robert D. Abbott, Ph.D. NR99-1050 (Circ/Abbott)
Media advisory:
Dr. Abbott may be reached by calling 808-524-3595;
Peter
Snell can be reached at 214-648-9187. (Please do not publish telephone
numbers.)