In this large 16-year prospective cohort study of premenopausal women, an increase in time spent bicycling was associated with a significantly lower change in weight, and this relationship was stronger among women with excess weight. For women who did not bicycle in 1989, less weight gain was evident for even a small increase to ≤5 min/d in 2005. Conversely, women who bicycled for ≥15 min/d in 1989 were at a higher risk of weight gain if they decreased or stopped bicycling in 2005.
Although brisk walking, unlike slow walking, has been suggested as a beneficial PA, only 39% of the women reported they walked briskly at baseline, while 50% reported they walked slowly. Walking briskly can be difficult, especially for women who are overweight/obese or those with arthritis or other disabilities.34
Overweight women spent half the time walking briskly (5.4 min/d) compared to lean women (10 min/d) while overweight and lean women spent comparable times bicycling (2 and 2.7 min/d, respectively).
Unlike discretionary gym-time, bicycling could replace time spent in a car for necessary travel of some distance to work, shops, or school as activities of daily living. Bicycling could then be an unconscious form of exercise because the trip’s destination, and not the exercise, could be the goal.35
Research on bicycling in addition to walking is relatively new.36
Although bicycling was found to be inversely associated with weight gain, fewer studies have included women, many studies have combined walking and bicycling, and several studies have been conducted in countries with bicycle environments different from the U.S. Our findings agree with Littman et al37
who conducted a study in western Washington state and found that fast bicycling, and not slow walking, in non-obese men between the ages of 53 and 57 was associated with weight attenuation. Though the age range was similar to the women in our study, this population only included lean males. In France and Northern Ireland, Wagner et al38
studied 8865 men aged 50–59 and found that men who walked or bicycled to work for ≥30 min/d had a lower body mass index (BMI) of 0.3 kg/m2
, a smaller waist circumference of 1 cm, and body mass change of 0.06 kg/m2
compared to men who did not walk or bicycle to work. While this study agreed with our positive association between brisk walking, bicycling and obesity reduction, the study only included males and walking was not differentiated between slow and brisk even though the walking was ≥30 min/d.
In an Australian study which included men (n=3810) and women (n=3022), Wen and Rissel39
determined that men who bicycled to work (n=93) were significantly less likely to be overweight and obese (39.8%) compared to those who drove to work (60.8%) but these inverse relationships were not evident in the women studied (n=10), which could be due to the lack of power. In both men (n=195) and women (n=216), walking to work was not associated with overweight or obesity and the authors suggested this may be because walking was not sufficiently vigorous or the distance was not great enough to affect weight. Their findings concur with ours. Bicycling by the men in that study was associated with less weight gain.
Hemmingsson et al36
conducted a randomized trial in abdominally obese women (30–60 years of age) with success defined as bicycling ≥ 2 km/d (primary) or walking 10,000 steps per day (secondary) for an 18-month duration. The intervention group members were given bicycles and followed a PA prescription of walking or bicycling while the control group members were given program support and pedometers. The intervention group was more likely to bicycle than the control group (38.7 vs 8.9%) while both groups had the same compliance rates for walking. Both groups achieved similar waist reductions (−2.1 and −2.6cm, P=0.72). Though none of the participants reported bicycling at baseline, 29% of the women bicycled as part of the intervention group. In our study, overweight/obese women bicycled for approximately the same amount of time as lean women but did not walk briskly the same amount of time as lean women. The study conducted in Sweden supports our finding that overweight/obese women will bicycle and can then achieve weight control.
While our research found significant associations between bicycling and less weight gain, dose response associations, and greater benefits for overweight/obese women, as previously shown in other studies,25, 26, 40
our research also revealed how few women bicycled for a substantial period of time. Though 48% indicated they bicycled and, they may have been on a stationary machine, they bicycled on average for only 2.5 min/d. Of these bicyclists, only 13% bicycled for ≥10 minutes/day at baseline and only 1.2% bicycled for 30 min/d or longer. Perhaps more women did not bicycle for longer periods because of a lack of bicycle environments comfortable to them and an emphasis in the U.S. on walking. Compared to bicycling,7
multiple studies have been conducted on walking, described as the “near perfect form of exercise.”5
Perhaps walking has been identified as beneficial because it has been compared, in the U.S. car-centric nation, to not walking.41, 42
The research that has been conducted on bicycling in the U.S. has included bicycle environments based on the American Association of State Highway and Transportation Officials (AASHTO) bicycle guidelines18
and the Federal Highway Administration (FHWA) teachings43
which favor roads, lanes, and shared-use paths. The guidelines have been based primarily on the perceptions of male bicyclists perhaps because more males bicycle21
and the studies have thus included a higher percentage of male respondents.8–10
Research conducted in Minnesota, Canada, and Australia, suggested females have a greater preference for separation from vehicle traffic.44–47
Compared to the U.S., the Dutch use 50- to 60-year old male and female bicyclists as the design models in their bicycle facility guidelines48
and these guidelines detail bicycle-exclusive cycle tracks and cycle track intersection and curb cut treatments.19, 49
On Dutch roads with car speeds of 80 km/h (49.71 miles per hour), a separate cycle track is recommended parallel to the road and on Dutch roads which bicyclists share with cars, the recommended car speed is 30 km/h (18.6 miles per hour).19
Though the Netherlands might be acculturated as a bicycle country, Canada’s Quebec bicycle design handbook features cycle tracks and other European bicycle facilities.50
As a result of being car-centric or being overly cautious about trying different bicycle facilities, in the U.S., 9% of the population walks for commuting whereas only 0.5% commutes by bicycle.24
In the Netherlands, 22% of the population walks and 27% commutes by bicycle.20
Individuals who have available comfortable bicycle infrastructure may still require individual determinants, such as self-efficacy and interest in bicycling, but they have, as a start, the infrastructure. Notably, if individuals have comfortable bicycle environments and they then bicycle, they are less likely to have medical risk factors and likely to have lower overall mortality. 51–54
Strengths and Limitations
There are several limitations to this study. First, the sample was not a random sample from the United States and the women in the study were better educated (all nurses) and primarily Caucasian. Second, our PA measurements are inevitably imperfect, which would tend to attenuate the association between PA and weight control. While objective measures of PA may have been desirable, the validity of our self-reported PA questions has been documented.27, 55
Third, the intensity of bicycling was not recorded and the assessment did not discriminate between regular biking and riding a stationary bicycle,. Fourth, only recreational physical activity was assessed and not total physical activity, (i.e., not time spent in activity doing housework or nursing work). Finally, although the different activities were analyzed in terms of min/d, information about the frequency of bicycling is lacking from our questionnaires such that we are unable to determine if there is any difference between someone engaging in 70 min/week all at once vs. someone bicycling 10 minutes every day.
These limitations notwithstanding, there are several strengths. First, this research included a large sample size followed with repeated measurements over 16 years. Second, women with conditions affecting weight such as pregnancy-related or post-partum weight gain were excluded. Finally, information on a wide variety of potentially confounding behavioral and demographic variables was collected at every assessment, which allowed us to assess different activity types and weight change associations independent of these potential confounders.