What is the fine-grained topic of the following text: While some of the growth will come from an aging population that requires more health-related monitoring at home, devices like the Fitbit Force activity band — which tracks a wearer’s steps, calories burned, sleeping patterns and progress toward fitness goals — are also expected to gain popularity as deskbound workers look for new ways to watch their waistlines. Only return the topic.
Increasing popularity of health monitoring devices like Fitbit Force activity band