Wearable activity trackers, such as Fitbit, can help predict how cancer patients will do on chemotherapy.

Jorge Nieva, MD, of the University of Southern California in Los Angeles, and colleagues analyzed data from 65 people undergoing treatment with chemotherapy that causes nausea and vomiting. They were asked to wear a Microsoft Band tracker for nine hours a day for two months. Among the 41 people who actually wore the trackers consistently, only nine recorded more than 60 hours of non-sedentary activity over the course of 60 days. But those who did so were less likely to experience severe side effects and other complications leading to unplanned hospitalization.

The researchers suggested that activity trackers could help identify patients in need of intervention to prevent hospitalization and may predict those who are more likely to report serious adverse events in clinical trials. Hundreds of trials are now incorporating fitness trackers as an objective measure of quality of life.