The intervention group will receive a Fitbit, SMS and will be assigned to a private Fitbit community (4-5 participants per group) for 12 weeks. During the intervention, participants will receive weekly personalized SMS on their mobile phones including encouraging messages, reminders, and tips to increase steps, and weekly step goals. The investigators will use a secure, web-based platform, iCardia, to support continuous real-time remote monitoring of activity data from Fitbit devices and personalized communication via SMS based on incoming data. The investigators will set up the Fitbit networking settings on participants' phones to give notifications when there are posts to this group. Individual goals and a weekly team goal of steps will be set up by the research team. Each member will be awarded a badge upon reaching each individual's weekly goal. Teams will also be awarded badges when all team members reach their individual weekly goals.

The attention control group will also receive a Fitbit and will be asked to continue with normal daily activities. During the initial in-person session, they will receive the same PA recommendations as the intervention group to walk at least 30 minutes for 5 days or more a week or 10,000 steps a day. However, a plan for improving PA will not be discussed.

The frequency and content of weekly personalized SMS are based on each participant's preference. Prior to implementation of intervention, the investigators will conduct focus groups to learn participants' social network activities and preferences, strategies that can be used to encourage engagement via a private Fitbit community network.

daily steps

modified six-minute walk test

Physical Activity Self-efficacy/Social Support scale will be used to assess confidence to perform physical activity