Short sleep duration is highly prevalent and linked to negative mental and physical health consequences, including increased cardiovascular disease risk [1]. According to data from the National Health Interview Survey, 70.1 million U.S. adults (29.2%) sleep <6 hours per 24 hour period [2]. These statistics are a stark contrast to recommendations made by a recent consensus panel of sleep experts that concluded "at least 7 hours" is the amount of sleep needed for health and performance among adults [3]. Therefore, a high number of U.S. adults could benefit from extending sleep duration. Several small experiments have demonstrated the benefits of short-term sleep extension [4-8]. However, these studies are limited by extending sleep as a temporary experimental manipulation rather than a longer-term behavioral intervention. To deliver sleep extension interventions, wearable sleep trackers may be useful, particularly given the rapid uptake among consumers (+500% in 3 years) [9]. We have developed a novel technology-assisted behavioral sleep extension intervention that employs four elements -- a wearable sleep tracker, didactic content, an interactive smartphone feature and brief telephone counseling. User testing supports feasibility of extending sleep, but little is known about the effects of differing types of technology interventions on sleep. Therefore, the goal of this study is to examine the differences between technology sleep extension interventions and sleep duration.

Study Design - Intervention

• Web or phone prescreening: Participants will first complete a brief online screening to determine initial eligibility criteria (self-report of medical and psychiatric conditions, sleep disorders). Individuals who are potentially eligible will be sent an Actiwatch via FedEx, along with training instructions. Participants will wear the Actiwatch for a 7-day prescreening assessment. Research staff will receive verbal consent for this screening procedure and will go over instructions over the phone to ensure participants understand how to use this device.
• Study Visits: Visit 1- Screening assessment: Participants will attend a one hour laboratory visit that will include consent procedures, standardized measurements of height, weight, waist and hip circumference, and blood pressure. Participants will complete baseline study questionnaires.
• Enrollment: During visit 1, staff will review eligibility. Participants will be informed at the end of visit one of their eligibility. If the participant is eligible, they will receive a verbal and written instructions and informing them of their study group assignment. If they are not eligible, a payment will be sent via check.
• Randomization: Participants will be randomized to 4 study groups using sealed envelopes with assignments determined via a random number generator.
• Study Conditions: Participants will be randomly assigned to 1 of 4 study groups.
• Study group 1: Participants will receive the telephone coaching and wear the Fitbit device week 1 through week 6.
• Study group 2: Participants will receive the telephone coaching only.
• Study group 3: Participants will wear the Fitbit device week 1 through week 6 study but will not receive telephone coaching.
• Study group 4: Control group. Participants will not receive telephone coaching nor will they wear the Fitbit device. They will be instructed to keep their sleep schedule consistent.

Arms and Interventions -

• The intervention will be delivered via smartphone and adherence will be facilitated by telephone coaching. Participants will receive weekly "lessons", which are content that is emailed each week as part of the program. In study groups 1 and 3, participants will wear a Fitbit sleep tracking monitor for the duration of the intervention. Coaches will be able to log in and see participants' data to help encourage them to meet their sleep goals.
• Weekly lesson content will be delivered via email (e.g. mail chimp).
• Telephone coaching: Participants in study groups 1 and 2 will be assigned to a sleep coach who will monitor their progress during the study and provide weekly telephone coaching sessions related to their sleep-related goals. The coaches will establish legitimacy by their knowledge of sleep and basic counseling principles. They will establish goals with the participants based on the participants' values and beliefs, including the particular sleep related goals and also usage goals, (e.g., number of log-ins completed per week). Performance monitoring will be completed through an online dashboard visible to the coaches (Fitbit web log in). The first coaching session is a 20 min engagement session, which includes introductions, rational for the program, clarifying roles of the coach and the participants' goals for the program. Coaches (directed by Dr. Baron) will provide feedback to the participant based on Fitbit and sleep diary data. For weeks 2-6, the coach and participant will also have weekly brief (5-10 min) follow-up support calls to troubleshoot any problems with the application or Fitbit, review progress, problem solve barriers to progress, and set goals for the following week. In-between sessions, the coaches will be available, mostly over email, to troubleshoot any problems with the content or Fitbit. Frequency of text, phone, and email communication will be recorded.
• Control group: Participants assigned to the no-treatment wait list control condition will be told they were assigned to the wait list group, and therefore eligible to receive the intervention components at the end of the study. At the end of the final session, they will receive a Fitbit wearable fitness tracker and emails with the 6 didactic lessons.

Inclusion Criteria:

1. BMI >25 kg/m2
2. Short sleep duration (<6.5 hrs of sleep per night, on average)

Exclusion Criteria:

1. High risk or presence of restless legs syndrome or insomnia as assessed by the screening questionnaires,
2. History of cognitive or neurological disorders;
3. Presence of any major psychiatric disorder, current alcohol or substance abuse;
4. Unstable or serious medical illness;
5. Shift work or travel over 2 time zones in the past 2 months,
6. Inability to read and write English,
7. Pregnancy or desire to become pregnant during the study period,
8. Significant environmental factors disturbing sleep (e.g. awakenings >4 per week due to caregiving responsibilities),
9. >8 hours in bed on average,
10. engaged in special diet for weight loss (e.g., diet post weight loss surgery),
11. use of hypnotics within the past three months.