Q: I got a new fitness tracker that I hope will help me be more active. Looks great but will it really count steps accurately and tell me how many calories I burn?
A: Fitness trackers—both wrist worn and pedometers—can be helpful tools for tracking physical activity and as a reminder to get moving. Physical activity is so important for your health, including cancer prevention. Studies show that both tools accurately count steps taken in moderate to fast walking and jogging, usually within three to five percent of actual steps taken. They are not designed to track certain types of exercise, such as strength-training and calisthenics.
Both wrist-worn trackers and pedometers tend to be much less accurate in estimating calories burned. They rely on built-in formulas that convert step counts to distance moved and then to calories burned. That leaves a lot of room for error due to individual differences in body size, metabolism and exercise details. These trackers can over- or under-estimate calories burned by at least 10 to 20 percent compared to metabolic measurements of actual calories burned.
Still, research does support using pedometers and other trackers to help boost physical activity, especially if you were to set a step goal. For example, in studies of pedometer use, people using pedometers increased daily step totals by over 2,000 per day, about a mile for an average adult.
Wrist-worn fitness trackers may include additional features that track sleep, sitting time or vigorous activity. Some are compatible with smartphones and computers so you get a progress record for personal use, or to share with friends for support, or with a health professional or coach. Since whatever you choose is only helpful if you wear it and check it, find one that is comfortable, easy to use, and includes the features that you will use.