Release Date: June 30, 2005
WEATHER
AFFECTS WORKOUTS, STUDY FINDS
By Lisa Esposito, Editor
Health Behavior News Service
Residents of cool, dry Montana are the most likely to get enough physical
activity, and residents of hot, steamy Puerto Rico the least, according
to a new research study that links climate conditions with physical
activity in the United States.
Lead researcher Ray Merrill, a professor at Brigham Young University,
and colleagues matched data from 255 weather stations with results
from a physical activity survey of people in 355 U.S counties, in a
study reported in the July/August issue of American Journal of Health
Behavior.
“It’s pretty obvious that weather influences physical
activity,” Merrill says. “It’s intuitive that cooler,
milder weather days are associated with more activity — but it’s
never really been quantified before.”
After Montana, with 60.9 percent, the states with highest percentages
of respondents meeting recommended physical activity levels were Utah
with 59.2 percent, Wisconsin with 57.9 percent and New Hampshire with
55.9 percent.
After Puerto Rico, at 30.9 percent, the states with the lowest percentages
were Hawaii with 36.4 percent, North Carolina with 37.4 percent and
Kentucky with 37.6 percent.
On analyzing the data, Merrill
says, “I was surprised by the
extremely strong correlation we found between physical activity and
weather conditions.” The researchers were also struck by the
very low levels of physical activity in some tropical areas.
Physical activity also varied significantly among seasons, with activity
highest in summer at 48.4 percent, 46.2 percent in spring, 45.8 percent
in fall, and 44.6 percent in winter.
Weather measurements — taken four times a day at each weather
station — included daily air temperature, dew point temperature,
wind speed direction, sea level pressure and total cloud cover.
To gauge physical activity, the researchers took data from an ongoing
national telephone survey of adults 18 and older, a project between
Centers for Disease Control and Prevention and U.S. states and territories.
The research team found that highest physical activity was linked
to moist moderate conditions in winter, dry polar in spring, dry tropical
in summer and moist polar in fall.
Moist tropical air is warm
and very humid, the researchers say, with cloud cover in winter and
partial cloud cover in summer. Muggy conditions “are
consistently associated with lowest mean percentages meeting recommendations
for physical activity,” the researchers found.
Dry tropical air is warm and sunny. Polar air, which leads to coldest
conditions, can be either dry with little cloud cover or moist with
cloud cover and, often, precipitation.
Counties that ranked in the top quarter for physical activity had
the highest percentage of dry, moderate days, followed by moist polar
days, then dry polar. Counties in the bottom quarter had highest percentage
of days in moist tropical conditions.
Researchers note that the data could have been slightly skewed by
physically active people who move to an area specifically for its climate,
for instance, skiers who seek moist, moderate winter conditions.
Recommended exercise was defined as 30 minutes of moderate physical
activity five to seven days a week or 20 minutes of vigorous physical
activity three to seven days a week. Moderate activity included brisk
walking, biking, vacuuming, and gardening; vigorous activity included
running, aerobics and heavy yard work.
For many people, the benefits
of exercise aren’t enough to tempt
them outdoors in sweltering or frigid climates. For some, such as the
elderly, the risks might outweigh the benefits.
“The paper, in part, was a call for an increase in indoor facilities
and for more programs tailored to the elderly, who would be more susceptible
to extreme conditions,” Merrill says.
Merrill R. Climate conditions and physical activity in the United
States. American Journal of Health Behavior 29(4), 2005.
FOR MORE INFORMATION:
Health Behavior News Service: (202) 387-2829 or www.hbns.org.
Center for the Advancement of Health
Contact: Ira R. Allen
Vice President of Public Affairs
202.387.2829
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