Presently 98 % of young adults own a cellular/mobile telephone (cell phone) and they use these devices heavily (>4 h day−1) [1]. There is also evidence that this heavy cell phone use occurs in seemingly every imaginable setting (e.g., in college classes, while driving, in bed, during sex, in the shower etc.) [2, 3]. In other words, many young adults are using their cell phones often and everywhere. Because of the omnipresence of cell phone use, researchers have begun to examine how these devices may be affecting other behaviors and behavioral outcomes. For example, excessive cell phone use has been linked with an increased incidence of traffic accidents, elevated anxiety, lack of sleep, poor academic performance and lower cardiorespiratory fitness [2, 4–12]. Taken together these findings indicate that excessive cell phone use may be considered a negative health behavior.
Previously, our group has examined associations between cell phone use and a range of health behaviors and outcomes [5, 13, 14]. We have reported an inverse relationship between cell phone use and cardiorespiratory fitness and a positive relationship between cell phone use and sedentary behavior [5, 13]. Additionally, we examined the effect of cell phone use on average walking speed during a bout of treadmill exercise in a controlled laboratory environment [14]. Using the cell phone to talk or send text messages significantly decreased treadmill walking speed relative to a condition with no cell phone use. This result is similar to another laboratory study by Parr et al. that utilized motion capture and an 8 m track to demonstrate that subjects had impaired gait mechanics and walked more slowly while texting versus a condition with no cell use [15]. These findings are potentially important if they translate to actual walking behavior as walking is the most commonly reported form of physical activity [16, 17].
There is evidence that individuals use their cell phones while walking and that this use is associated with increased risk of injury [7–11]. However, other than the aforementioned laboratory-based studies, there is only a single study that we are aware of which examined how cell phone use affects free-living walking pace in a field setting [18]. This previous study examined the effects of cell phone use on attention while walking across a large open area on a college campus. The open area was a central student gathering place and posed a “complex navigational task” (p. 599) for the subjects. It demonstrated that, under these conditions, talking on a cell phone while walking led to inattentiveness, increased weaving and directional change, and greater time needed to traverse the open area relative to non-users. However, it remains unknown if cell phone use increased the time it took to complete this “complex navigational task” because cell use actually slowed walking pace or if it simply added to the difficulty of traversing the open area (e.g., increased weaving and directional change). If the greater time to traverse the open area was due to increased weaving and direction change and not a decrease in walking speed, cell phone use while walking may actually increase total walking behavior while maintaining speed. This would be a positive outcome. To assess whether cell phone use actually decreases free-living walking speed there is a need to investigate how cell phone use affects free-living walking in a setting relatively free of distraction and navigational challenge. In addition, this prior study only examined talking on a cell phone. There is a need to assess the effect of increasingly common cell-phone based activities that require the user to look at the device (e.g., texting, watching a video).
A greater understanding of how cell phone use may affect walking behavior is important as walking is the most commonly reported form of physical activity and for many individuals walking for active transport (i.e., getting from one place to another) is the only daily physical activity they participate in [16, 17]. While the amount of walking (i.e., duration, distance) individuals participate in is positively associated with a number of health benefits, walking pace is emerging as a stronger predictor of cardiovascular disease risk. Recent articles from Boone-Heinonen et al. and Saevereid et al. both indicated that walking pace, more strongly than distance or duration, was inversely associated with cardiovascular disease risk factors and congestive heart failure [19, 20]. Therefore, if individuals regularly use their cell phones while walking and this use reduces walking speed then it is possible that these slower walking speeds could increase the risk of cardiovascular disease.
The purpose of this study was to compare average speed during free-living, active-transport walking while individuals were holding a cell phone to their ear (talking), actively utilizing the phone with their hands and looking at the screen (texting), or not using a cell phone (no use). Naturalistic observations were made, unbeknownst to the subjects, in a field setting as individuals traversed a 50 m straight walkway on an American college campus. We hypothesized that individuals who were talking or texting on a cell phone would walk more slowly than individuals who were not using their cell phone.