Should you use a pedometer when you exercise? Johns Hopkins provides advice.

Pedometers have become increasingly popular in the last few years, particularly in the wake of the American Heart Association’s (AHA) Start! campaign, which provides participants with discounted pedometers and other tools to promote exercise.

The most recent evidence supporting their use comes from a study in the Journal of the American Medical Association. Data pooled from 26 studies totaling 2,767 participants found that people who used pedometers walked about one mile more per day than those who did not use pedometers. Other benefits included a 27% average increase in physical activity, a 3.8–mm Hg drop in systolic blood pressure, and a 0.38- point decrease in body mass index.

But pedometers alone didn’t boost activity. The participants who benefited most also recorded their progress benefited in “step diaries” and set step goals, such as 10,000 per day. To achieve this goal, the AHA recommends adding 1,000 steps each week to your walking routine until you reach 10,000.

All pedometers are not created equal. According to a study from the University of Tennessee, piezoelectric pedometers (also called accelerometers) count the steps of overweight adults more accurately than less-expensive spring-levered pedometers, especially at slower walking speeds. Extra inches around the waist can cause pedometers to tilt and skew results in spring-levered models.