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Earlier this month, I blogged about exercise safety in "Exercise 1: checking it's safe to start" , about the helpful GPPAQ - General Practice Physical Activity Questionnaire - described in "Exercise 2: UK Department of Health, resources for assessment & advice", and excellent advice on how to exercise in "Exercise 3: US Department of Health & Human Services, resources for assessment & advice".  In today's post, I want to talk about the value of pedometers - the little gadgets we can use to count the number of steps we take.

Pedometers can be surprisingly effective at motivating us to walk further.  Bravata & colleagues looked at 26 research studies on pedometers in their paper "Using Pedometers to Increase Physical Activity and Improve Health: A Systematic Review" (see below for link and full abstract).  They found that, overall, pedometer use led to more than 25% increase in distance walked over the average 18 week duration of the investigations.  They concluded "The results suggest that the use of a pedometer is associated with significant increases in physical activity and significant decreases in body mass index and blood pressure."  More recently still, Cobiac & colleagues wrote in their paper "Cost-Effectiveness of Interventions to Promote Physical Activity: A Modelling Study" (see below), "There are many options for intervention, from individually tailored advice, such as counselling from a general practitioner, to population-wide approaches, such as mass media campaigns, but the most cost-effective mix of interventions is unknown."  After reviewing the literature, they concluded  "Based on current evidence of intervention effectiveness, the intervention programs that encourage use of pedometers ... and mass media-based community campaigns ... are the most cost-effective strategies to implement and are very likely to be cost-saving."

Wikipedia has an interesting & informative article about pedometers and the Scottish "Paths to Health" website also makes some helpful comments.  Probably most useful overall is the practical advice given on page 47 of the full "Physical activity guidelines for Americans, 2008"  where they state: 

"For adults who prefer walking as a form of aerobic activity, pedometers or step counters are useful in tracking progress toward personal goals. Popular advice, such as walking 10,000 steps a day, is not a Guideline per se, but a way people may choose to meet the Guidelines. The key to using a pedometer to meet the Guidelines is to first set a time goal (minutes of walking a day) and then calculate how many steps are needed each day to reach that goal.

Episodes of brisk walking that last at least 10 minutes count toward meeting the Guidelines. However, just counting steps using a pedometer doesn't ensure that a person will achieve those 10-minute episodes. People generally need to plan episodes of walking if they are to use a pedometer and step goals appropriately.

As a basis for setting step goals, it's preferable that people know how many steps they take per minute of a brisk walk. A person with a low fitness level, who takes fewer steps per minute than a fit adult, will need fewer steps to achieve the same amount of walking time.

One way to set a step goal is the following:

1. To determine usual daily steps from baseline activity, a person wears a pedometer to observe the number of steps taken on several ordinary days with no episodes of walking for exercise. Suppose the average is about 5,000 steps a day.
2. While wearing the pedometer, the person measures the number of steps taken during 10 minutes of an exercise walk. Suppose this is 1,000 steps. Then, for a goal of 40 minutes of walking for exercise, the total number of steps would be 4,000 (1,000 × 4).
3. To calculate a daily step goal, add the usual daily steps (5,000) to the steps required for a 40-minute walk (4,000), to get the total steps per day (5,000 + 4,000 = 9,000).

Each week the person gradually increases the time walking for exercise until the step goal is reached. Rate of progression should be individualized. Some people who start out at 5,000 steps a day can add 500 steps per day each week. Others, who are less fit and starting out at a lower number of steps, should add a smaller number of steps each week."

So the bottom line is (if you use, or want to use, walking as a significant part of your overall exercise programme), consider getting a pedometer.  Online stores like Amazon UK stock a wide variety.  As Cobiac & colleagues found in their research - a pedometer is likely to pay for itself many times over if it helps you become a bit fitter.

Next week I'll blog on "Exercise 5: the recommendation to do strengthening exercises".

Bravata, D. M., C. Smith-Spangler, et al. (2007). "Using Pedometers to Increase Physical Activity and Improve Health: A Systematic Review." JAMA 298(19): 2296-2304.  [Free Full Text]
Context Without detailed evidence of their effectiveness, pedometers have recently become popular as a tool for motivating physical activity. Objective To evaluate the association of pedometer use with physical activity and health outcomes among outpatient adults. Data Sources English-language articles from MEDLINE, EMBASE, Sport Discus, PsychINFO, Cochrane Library, Thompson Scientific (formerly known as Thompson ISI), and ERIC (1966-2007); bibliographies of retrieved articles; and conference proceedings. Study Selection Studies were eligible for inclusion if they reported an assessment of pedometer use among adult outpatients, reported a change in steps per day, and included more than 5 participants. Data Extraction and Data Synthesis Two investigators independently abstracted data about the intervention; participants; number of steps per day; and presence or absence of obesity, diabetes, hypertension, or hyperlipidemia. Data were pooled using random-effects calculations, and meta-regression was performed. Results Our searches identified 2246 citations; 26 studies with a total of 2767 participants met inclusion criteria (8 randomized controlled trials [RCTs] and 18 observational studies). The participants' mean (SD) age was 49 (9) years and 85% were women. The mean intervention duration was 18 weeks. In the RCTs, pedometer users significantly increased their physical activity by 2491 steps per day more than control participants (95% confidence interval [CI], 1098-3885 steps per day, P < .001). Among the observational studies, pedometer users significantly increased their physical activity by 2183 steps per day over baseline (95% CI, 1571-2796 steps per day, P < .0001). Overall, pedometer users increased their physical activity by 26.9% over baseline. An important predictor of increased physical activity was having a step goal such as 10 000 steps per day (P = .001). When data from all studies were combined, pedometer users significantly decreased their body mass index by 0.38 (95% CI, 0.05-0.72; P = .03). This decrease was associated with older age (P = .001) and having a step goal (P = .04). Intervention participants significantly decreased their systolic blood pressure by 3.8 mm Hg (95% CI, 1.7-5.9 mm Hg, P < .001). This decrease was associated with greater baseline systolic blood pressure (P = .009) and change in steps per day (P = .08). Conclusions The results suggest that the use of a pedometer is associated with significant increases in physical activity and significant decreases in body mass index and blood pressure. Whether these changes are durable over the long term is undetermined.

Cobiac, L. J., T. Vos, et al. (2009). "Cost-Effectiveness of Interventions to Promote Physical Activity: A Modelling Study." PLoS Med 6(7): e1000110.  [Free Full Text] 
Background: Physical inactivity is a key risk factor for chronic disease, but a growing number of people are not achieving the recommended levels of physical activity necessary for good health. Australians are no exception; despite Australia's image as a sporting nation, with success at the elite level, the majority of Australians do not get enough physical activity. There are many options for intervention, from individually tailored advice, such as counselling from a general practitioner, to population-wide approaches, such as mass media campaigns, but the most cost-effective mix of interventions is unknown. In this study we evaluate the cost-effectiveness of interventions to promote physical activity.  Methods and Findings: From evidence of intervention efficacy in the physical activity literature and evaluation of the health sector costs of intervention and disease treatment, we model the cost impacts and health outcomes of six physical activity interventions, over the lifetime of the Australian population. We then determine cost-effectiveness of each intervention against current practice for physical activity intervention in Australia and derive the optimal pathway for implementation. Based on current evidence of intervention effectiveness, the intervention programs that encourage use of pedometers (Dominant) and mass media-based community campaigns (Dominant) are the most cost-effective strategies to implement and are very likely to be cost-saving. The internet-based intervention program (AUS$3,000/DALY), the GP physical activity prescription program (AUS$12,000/DALY), and the program to encourage more active transport (AUS$20,000/DALY), although less likely to be cost-saving, have a high probability of being under a AUS$50,000 per DALY threshold. GP referral to an exercise physiologist (AUS$79,000/DALY) is the least cost-effective option if high time and travel costs for patients in screening and consulting an exercise physiologist are considered.  Conclusions: Intervention to promote physical activity is recommended as a public health measure. Despite substantial variability in the quantity and quality of evidence on intervention effectiveness, and uncertainty about the long-term sustainability of behavioural changes, it is highly likely that as a package, all six interventions could lead to substantial improvement in population health at a cost saving to the health sector.