Earlier this year, the U.S. federal government issued new exercise guidelines that recommend adults and children spend at least an hour a day in moderately intense physical activity to maintain maximum cardiovascular health.
That's double the daily amount suggested in the 1996 U.S. Surgeon General's report.
While it's a good idea to encourage people to exercise, the new guidelines may actually discourage some people, says Dr. Howard Eisenson, director of the Duke Diet and Fitness Center, at Duke University Medical Center.
He says some people who aren't able to exercise for an hour may feel they have nothing to gain from exercising for shorter periods each day. But Eisenson says those short stretches of exercise do benefit people.
"I would probably disagree with the new guidelines because I think they could give people the impression that unless they're exercising for an hour a day, every day of the week, they're not getting much health benefit," Eisenson says.
"That's not really true. Research shows that the Surgeon General's recommendation from the mid-1990s is still a good one, and if people will exercise for 30 to 40 minutes most days, they will realize health benefits from that," Eisenson says.
That's a good first target for people who are sedentary and will provide them with health benefits. Once they master that amount of exercise, they may choose to increase their amount of exercise to an hour each day.
Eisenson reminds people they don't need to join a gym and use all the latest exercise equipment to get their exercise.
"Regular lifestyle activities are fine, including walking or doing chores around the house. Becoming more physically active is beneficial at whatever level. More might be better, but some is certainly a lot better than none," he says.
The American Heart Association has some exercise tips.