Using pedometers to increase physical activity in overweight and obese women: a pilot study

Obesity has reached epidemic proportions globally, with more than 1 billion adults overweight and at least 300 million of these clinically obese [1]. Obesity carries with it significantly higher risks for developing diabetes, hypertension, stroke, coronary artery disease, sleep apnoea, joint and respiratory problems [2–4].

Studies have shown that exercise can elicit improvements in cardiovascular fitness, body composition, blood lipid profile and retention of essential muscle mass [5]. Regular physical activity also improves, mental health states [6], blood pressure [7], type 2 diabetes [8], protects against some cancers [9] and the risk of osteoporosis [10]. Despite increased knowledge about the benefits of exercise, weight loss and a healthy diet for psychological and physiological well-being, motivating sedentary overweight obese adults is a difficult task. Even those who initiate changes often find it difficult to comply with a program for any length of time, most falling back into their old inactive habits after an intervention ends [11]. Most public health guidelines recommend that adults participate in 30 minutes of moderate intensity physical activity on most, if not all days of the week [12–15]. However, the 2008 US Physical Activity Guidelines Advisory Committee recommends that overweight/obese adults should accumulate at least 60 minutes of activity on most days of the week [16]. Ensuring that a sufficient amount of physical activity has been accumulated daily to attain health benefits can be very difficult, especially in the overweight and obese. Therefore, establishing new ways to achieve these higher targets need to be explored.

It is generally recommended that lifestyle-based (or home-based) increases in physical activity, as opposed to structured exercise programs (gym, walking trainers, supervised programs) are more likely to be successful in facilitating increased physical activity and weight loss over the long-term [17, 18]. Studies have shown that the daily use of pedometers is associated with significant increases in physical activity [19]. Feedback from pedometer step counts has been shown to prompt behaviour change as they raise awareness of current walking behaviours [20], can be used to motivate [21], and to self-monitor [20, 21]. A meta-analysis of 26 RCTs and observational studies of pedometer use in adults reported a significant increase in the number of steps walked per day [19]. However, the authors concluded that some limitations of the included studies were: 1) the studies were all of relatively short duration and the extent to which these results are durable over the long term is unknown; 2) few studies provided detailed information about their participants or evaluated more than one of the outcomes of interest 3) many interventions included the use of two or more components (eg, pedometers, step goals, diaries, counselling). Hence studies investigating pedometer use without a step goal and/or without physical activity counselling are required, including comparisons between participants who can see their daily step counts vs pedometer use in which they are blinded to their daily step counts.

The aim of this pilot study was to investigate whether the daily recording of steps using pedometers could increase physical activity in sedentary overweight and obese women. We hypothesised that the daily use of pedometers would act as prompt to increase daily physical activity in sedentary overweight and obese women. In this study middle-aged women were targeted as > 50% of this group are overweight and therefore at high risk for developing cardiovascular disease, diabetes and hypertension [2]. Women are specifically targeted in this pilot study as they generally have a large input into their families. Thus, any lifestyle changes have the potential to flow on and affect their family members (spouses, children).

Our results are consistent with previous research indicating that the daily use of pedometers is effective in increasing walking behaviour. A meta-analysis of 26 RCTs and observational studies of pedometer use in adults reported a significant increase in the number of steps walked per day [19]. Participants in the RCTs who used pedometers, recorded their steps and had a step goal increased their physical activity by an average of 2491 steps per day more than pedometer users who did not have a step goal. In the meta-analysis study, pedometer users increased their number of steps by 27% over baseline [19]. Bravata et al., [19], found that step-count goal was an important predicator of increasing physical activity. Similarly in our study, those in the control group who were not given a daily step goal and unable to open their pedometers on a daily basis, had no significant increase in their physical activity over baseline. On the other hand, the pedometer group had a step goal, were able to open view their pedometer on a daily basis and record steps. Since pedometers provide a quantifiable walking measure, they enable participants to track and record progress from a baseline reference point. Studies have shown that immediate feedback from the pedometers enable participants to set realistic goals, act as an environmental cue, raise awareness of current walking behaviours [20], to motivate [21], to self-monitor [20, 21], and to increase walking behaviours [7, 28].

We did not observe any changes in anthropometric measures in this study, which is consistent with other studies [29]. It has been suggested that 60 to 90 min of moderate intensity exercise on most days of the week would be required for weight loss [30]. Therefore, the extra 3461 steps steps/day (equivalent to 30 min of physical activity) performed by the pedometer group may not have been adequate to see changes in anthropometric measures in this group [31]. Anthropometric measures may have remained stable, despite increased physical activity, due to nutritional compensation. However, we did not observe any increase in dietary intake at 12 weeks (Table 3). Lack of change in nutritional intake may be due to under reporting by overweight and obese groups as shown in previous studies [32, 33].

Current public health guidelines suggest that ≈ 30 min of moderate-intensity activity/day on most days of the week provides health benefits and reduces risk for a range of conditions in all population groups [12–14]. However, new recommendations by the US Physical Activity Guidelines Advisory Committee suggests that overweight/obese adults should accumulate at least 60 minutes of activity on most days of the week for weight loss [16]. Brisk walking for 60 minutes is equivalent to approximately 6,000 steps [34]. This means that overweight individuals would need to accumulate an extra 6000 steps for weight loss. Therefore, new ways are required to help achieve this higher target. In our study, sedentary overweight and obese women were asked to comply with the National Australian guidelines for adults and increase their physical activity by 30 min/day. Those in the pedometer group with 6242 ± 541 steps/day at baseline, reached an average of 9703 ± 921 steps/day after 12 weeks, an increase of more than 3000 steps/day. However, overweight adults in our study would need to accumulate at least 12,000 steps per day to comply with these new guidelines and achieve weight loss. As suggested by the the US Physical Activity Guidelines Advisory Committee, energy intake (diet) must be also be considered for weight control by this particular group [16].

The increase in daily steps in the pedometer group was mainly through walking more (Table 4). It has been previously demonstrated that walking is the single easiest way for people to increase their physical activity and sustain it over the long term [35]. Walking, which is "self paced" is the most frequently reported physical activity and most preferred in the overweight and obese as it is low-impact with little risk of injury [12, 36, 37].

This study showed improvements in systolic blood pressure in the pedometer group after 12 weeks compared to the control group. As dietary intake in the pedometer group at 12 weeks did not significantly change from baseline we can comment that improvements in blood pressure are most likely due to an increase in physical activity in this group and unlikely to be influenced by any changes in dietary intake. In a meta-analysis of 26 RCTs and observational studies, intervention participants, who had increased their physical activity levels, had a statistically significant decrease in systolic blood pressure of 3.8 mm Hg and diastolic blood pressure of 0.3 mm Hg [19]. This reduction in systolic blood pressure was independent of decreases in BMI. Our results are also consistent with a meta-analysis of 54 studies conducted by Whelton et al. [38] showing that aerobic exercise reduced blood pressure in both hypertensive and normotensive adults. All frequencies, intensities, and types of aerobic exercise lowered blood pressure. By highlighting the health benefits of physical activity, health professionals can use such evidence to encourage overweight and obese patients, who are frustrated by an inability to lose weight, to engage in physical activity.

In this study we asked our overweight and obese participants to comply with the Australian Physical activity guidelines which advises most adults participate in 30 minutes of moderate intensity physical activity on most days. Further work is required to demonstrate whether using pedometers on a daily basis could help the overweight and obese accumulate at least 60 minutes of activity on most days of the week, thereby meeting the new recommendations for physical activity advised for this group [16]. It is possible that changes in anthropometric measures could be observed after 12 weeks in this group with 60 min targets. One of the limitations of this study was using a pedometer without a memory chip, where only a total step count for the week was available for the control group. There is evidence to suggest that despite participants not being able to see their daily step count when wearing sealed pedometers, a certain amount of reactivity (i.e. steps are higher) occurs during the first 2–3 days of monitoring under these conditions [39]. For future studies using pedometers with a memory chip which is capable of storing daily step counts over a period of seven days could be used. A study in overweight and obese adults has shown that a piezo-electric pedometer is more accurate than a Yamax Digi-Walker in those with higher BMI [40]. This type of pedometer could be used in future studies for studying walking behaviours in overweight and obese individuals. Another limitation of this study was the lack of detail in how the participants chose to perform their physical activity. It is also suggested that in addition to daily activity, exercise should be performed in bouts of 10 mins and resistance exercise should be performed two times per week [15, 29]. Although those in the pedometer group reported that they had increased their walking, the duration of each walking bout is unclear. Recommendations regarding resistance training were not highlighted to the participants.

In conclusion, this pilot study shows that the combination of having step goals and immediate feedback from using a pedometer was effective in increasing physical activity levels in sedentary overweight and obese women.