Writing texts while walking can alter posture and balance, say scientists who studied the effects of mobile phone use on 26 healthy volunteers.
Participants in the Australian study walked at a comfortable pace in a straight line over a distance of around 28 feet.
Each was asked either to walk without a phone, or to walk while reading or typing a text. At the same time, their body movements were analysed in three dimensions.
Texting, and to some extent, reading, was shown to modify body positioning while walking. While texting, participants walked more slowly and were more likely to swerve from a straight course.
Although the arms and head moved with the chest to facilitate reading and texting, increased head movement could have a negative effect on balance, said the researchers, whose findings are reported in the online journal Public Library Of Science ONE.
Texting pedestrians may be more at risk when navigating obstacles or crossing roads, they added.
Study leader Dr Siobhan Schabrun, from the University of Queensland in Australia, said: "Texting, and to a lesser extent reading, on your mobile phone affects your ability to walk and balance. This may impact the safety of people who text and walk at the same time."