August 20, 2014
News Review From Harvard Medical School -- Non-Car Commuters Thinner, Study Finds
Walking, biking or even riding public transit to work can help with weight control, a new study suggests. The study was based on a survey of about 7,500 people in the United Kingdom. Nearly 74% commuted by car. About 10% of men and 11% of women used public transit. About 14% of men and 17% of women walked or biked to work. A nurse visited people and measured their height, weight and percentage of body fat. Researchers adjusted the numbers to account for factors that may affect weight. These included age, medical conditions, income, social class and other exercise. They found that BMI was lower for those who did not drive to work. Effects were similar whether people commuted by foot, bicycle or public transit. For example, men in these groups had BMI scores between 0.9 and 1.1 points lower than the men who drove themselves. The difference was equal to being about 6.6 pounds lighter for a man or 5.5 pounds lighter for a woman of average height. The active and public-transit commuters also had less body fat. The journal BMJ published the study online. HealthDay News and Reuters news service wrote about it August 19.
By Howard LeWine, M.D.
Harvard Medical School
What Is the Doctor's Reaction?
We hear it over and over: Get more exercise. For many, finding the time to do it is the biggest obstacle.
Try leaving the car at home. If you live close enough to work, walking or biking to get there will help to shed pounds and body fat. And if you live too far from work, here's some good news. Commuting to work by bus, train or other public transportation may do the same, according to this study. BMJ, formerly the British Medical Journal, published the study.
The study results do not actually prove that commuting by public transportation was the direct cause for lower body weight and less body fat. What the researchers found is that average-sized adults who got to work using public transit weighed 6 to7 pounds less than those driving to work. They also had about 1% to 1.5% less body fat.
The researchers did try to account for differences in other exercise, as well as social and economic factors known to influence body weight.
It makes sense that commuting by public transit would be linked with a healthier body. It usually requires some walking or biking to get to and from the bus stop or train station. In fact, a prior study found that U.S. adults who use public transportation walk an average of 19 minutes as part of their daily commute to work.
What Changes Can I Make Now?
Leaving the car at home may not be an option for you. Here are some other ways to get more exercise while at work.
Get up and move often. One study compared workers who sat continuously for 5 hours with those who got up every 20 minutes to walk around briskly or perform some other exercise. The frequent movers had lower blood sugar and insulin levels. That's a good formula to keep down body fat.
Count steps. Don't do this just at work. Wear a pedometer all day long. It's a low-cost way to track your progress. You might not reach the widely touted goal of 10,000 steps. The goal is to keep increasing your steps from week to week.
Take longer walks at lunch time or when you are back at home. If you are a new walker, start at a comfortable level for you. Divide your walking into 3 parts:
- A slower pace to warm up
- A faster pace to get your heart pumping
- A slower pace to cool down
What Can I Expect Looking to the Future?
Cities and suburbs have taken some baby steps toward making it safer and easier for people to walk and bike to work. Much more needs to done, which will require major financial commitments. And reasonably priced, convenient public transportation would help encourage more people to leave the car at home.