Physical inactivity increases the risk of many chronic diseases, including coronary heart disease and type 2 diabetes. Yet many adults in the UK do not undertake the amount of physical activity recommended by the Department of Health – 150 minutes of moderate intensity physical activity per week, in periods of at least ten minutes at a time. One way for working adults to build regular physical activity into their daily lives is to walk during the daily commute.
Investigating walking to work
Walking has been described as near perfect exercise. It is free, familiar, carbon neutral, requires no special equipment or training, and can be easily combined with other modes of transport when making longer journeys. Walking at a speed of three miles (around five kilometres) per hour counts as moderate intensity physical activity, so the daily commute may be an easy way of clocking up the recommended amount of physical activity.
As part of the ‘Walk to Work’ feasibility study, DECIPHer researchers measured how much walking to work contributed to adults’ physical activity levels.
How was this done?
Seventeen workplaces were involved in the study – eight small (50 or fewer employees), five medium (51 to 250 employees) and four large (250 or more employees).
The amount and intensity of participants’ physical activity was measured for seven days using an accelerometer, a device worn on a belt around the waist. Each participant also wore a GPS receiver, allowing researchers to map when and where physical activity took place, and how long participants spent travelling. Additionally, participants were asked to record how they travelled, and how long it took, in a diary each day.
Of the 147 participants who lived within two miles of their workplace (‘walking distance’), 130 provided accelerometer data and information about their mode of transport. They were categorised as follows, according to their most common method of travel over the week when this was measured: usual walkers (n=70); usual drivers (n=33); usual cyclists (n=18); mixed/other (n=9).
Those categorised as ‘usual cyclists’ were not included in analysis, as the accelerometers could not accurately measure physical activity when cycling. Those using ‘mixed/other’ modes of transport were also excluded, leaving 70 walkers and 33 car users.
What were the findings?
Walking vs driving
Accelerometer data was used to identify the following for each participant:
- Total physical activity (measured in mean daily accelerometer counts per minute, or cpm);
- Time spent doing moderate to vigorous physical activity (MVPA);
- Time spent sedentary.
The following was found:
- Overall weekly physical activity was around 45% higher for those who usually walked to work, compared to those who travelled by car.
- Those who usually walked to work took part in around 19 minutes more of MVPA per day than those who usually travelled by car.
- There was no difference in the amount of sedentary time recorded between the two groups.
- By looking at when physical activity took place, it was found that the main differences in the physical activity of car users and walkers were in the morning and late afternoon – when they would be likely to be travelling to or from work.
- When looking just at weekends, the car users and walkers did not differ in their physical activity. This means that the car drivers were not making up the difference by being active at the weekends.
The contribution of walking to work
Fifty-eight people who walked to work also provided GPS data for at least one of their journeys. This was combined with accelerometer data to examine how much MVPA took place during the journey to and from work. It was found that the commute contributed nearly half (47.3%) of participants’ daily MVPA – on average, 38 out of 80.3 minutes.
Why is this important?
To our knowledge, this is the first study with adults to combine accelerometer and GPS data to examine the role of the commute in overall physical activity and MVPA. This research found that adults who usually walked to work had significantly higher levels of both total physical activity and MVPA than those who travelled by car. It also found that the journey to and from work was responsible for most of the difference in weekday physical activity between walkers and car users.
It is important to note that the findings discussed here cannot be generalised to the wider population, because of the small sample size and the characteristics of these participants (who were mostly well-educated, younger adults). The researchers conclude that the objective methods used in this study should be used in larger, more representative studies.
The findings of this research highlight the important contribution of walking to work to adults’ physical activity. This research suggests that developing interventions to increase walking to work may be an effective method of encouraging working adults to live healthier lives.
Audrey S, Procter S and Cooper A. The contribution of walking to work to adult physical activity levels: a cross sectional study. International Journal of Behavioral Nutrition and Physical Activity 2014, 11:37. doi:10.1186/1479-5868-11-37, which is available, open access, at http://www.ijbnpa.org/content/pdf/1479-5868-11-37.pdf
Dr. Suzanne Audrey is a research fellow at DECIPHer, based at the University of Bristol. Catt Turney is research and knowledge exchange assistant at DECIPHer, based at Cardiff University. She tweets at @CattTurney.