This study is a parallel group randomized controlled trial among female university students designed to test the effect of a physical activity intervention on daily walking. Both groups will receive messages 2-3 times per week via WhatsApp. Intervention group will receive orientation and wear a pedometer for the study period. The follow-up duration is 3 months.

Background: Sedentary lifestyle is a major risk factor for chronic diseases. The majority of Saudi females do not meet a recommended level of physical activity.

Study Objective: To test the effect of a physical activity intervention on daily walking.

Study Design: Parallel group randomized controlled design among female university students.

Methods: Students will be randomly assigned to either the intervention or the control arm. WhatsApp groups (2 per arm) will be formed within each study arm for communications. The intervention participants will receive a brief (15-minute) orientation on diet, exercise, and benefits of keeping a healthy weight; each will be instructed to wear a pedometer every day for 12-weeks with a daily step goal of 8,000. They will receive 2-3 health-promotional (walking and diet) messages per week via WhatsApp; group interaction is optional. The control group participants will receive 2-3 non-health related messages per week. Average daily steps will be assessed in all participants at baseline and 3-month follow-up using a 7-day pedometer measurement.

Inclusion Criteria:

• female
• student enrolled at Qassim University during 2016-2017 academic year
• owns smartphone with internet access
• willing to complete all study requirements

Exclusion Criteria:

• Physical disability that precludes physical activity
• Morbidly obese (Body Mass Index >45 kg/m2)
• Physician recommendation not to exercise