may boost HDL ("good") cholesterol levels.
But brief bouts of exercise may not be enough.
It may take at least two hours per week of aerobic exercise such as walking,
biking, or swimming -- preferably in sessions lasting for more than half an
hour -- to get the HDL benefit.
That's according to a new research review published in the Archives of
The reviewers, who work at the University of Tokyo, included Satoru Kodama,
MD. They pooled data from 25 studies on aerobic exercise and HDL
Together, the studies included some 1,400 adults, some of whom were assigned
to get aerobic exercise for at least eight weeks. Participants weren't told to
On average, participants worked out nearly four times per week, with each
workout lasting for about 40 minutes.
Rise in HDL Cholesterol
Participants who got at least two hours per week of aerobic exercise had a
modest rise in their HDL cholesterol level.
Unlike LDL ("bad") cholesterol, a rise in HDL ("good")
cholesterol is considered positive for heart health.
Based on other research, the reviewers estimate that the gains in HDL
cholesterol levels translate to a 5% drop in men's heart disease risk and more
than a 7% drop in women's heart disease risk.
"This is potentially of substantial importance in public health,"
write Kodama and colleagues. However, they say the benefit may be less than
that from drugs that boost HDL cholesterol.
Longer Workouts Better
The CDC recommends that people get at least 30 minutes of moderate-intensity
physical exercise at least five days per week.
Many people find it hard to devote long periods of time to exercise. So
Kodama's team tried to figure out whether several short sessions would raise
They concluded that workouts needed to last more than half an hour to
improve HDL cholesterol. However, further research is needed to confirm that
Exercise intensity didn't affect the findings. That is, it didn't matter
whether participants got vigorous exercise or worked out at a gentler pace.
The HDL benefits were greatest in people who weren't obese and those with
high levels of total cholesterol. The reasons for those findings aren't
Don't know your cholesterol levels? A simple blood test can give you that
information. Then you and your doctor can make a plan to improve your
cholesterol profile, if necessary.
By Miranda Hitti
Reviewed by Louise Chang
B)2005-2006 WebMD, Inc. All rights reserved