Early mobilization is an important element in Enhanced Recovery After Surgery (ERAS). It reduces risk of conditions which are related to prolonged bed rest such as deep vein thrombosis, lung atelectasis, pneumonia, and sacral sore. (Appelboom, Taylor et al. 2015) It is also associated with shortened length of hospital stay, improved survival, and reduction in health care cost.

However, "early mobilization" was not defined consistently in previous study. Some authors recommend patients to get out of bed and ambulate on the day of operation while others define as getting out of bed more than 2 hours on day of operation and up to 8 hours on second post-operative day. (Wolk, Meissner et al. 2017) The inconsistency in definition is partly due to the inability to quantify patients' mobility which is usually self-reported by patients and is subjective.(Eva van der Meij 2017) This is especially true for elderly patient in whom preoperative mobility varies significantly between individuals. For this reason, the approach of early mobilization in elderly should be goal directed and individualized according to their preoperative mobility and functional status.

The aim of current study is to monitor and motivate elderly patients undergoing abdominal surgery to increase postoperative mobilization by using Fitbit Zip activity tracker.

This is a randomized, controlled, single center trial comparing the use of activity tracker with and without automatic feedback in improving postoperative mobility of elderly patients undergoing abdominal surgery.

Selected subjects will be randomized into treatment and control groups in a ratio of 1:1.

Patients will be randomized upon enrollment using computer generated random assignment. Treatment group will be put on activity tracker device (Fitbit Zip) with automatic step counts feedback throughout the study. Meanwhile, control group will be put on same activity tracker without automatic feedback for same duration of intervention. The Fitbit Zip tracker (Fitbit Inc, San Francisco, California USA) is a validated commercially available activity tracker and its use has been proven accurate in elderly patients.

Subjects from both treatment and control group will be put on wristband starting from one week before the scheduled operation until 7 post-operative days. Patients will be instructed to wear the wristband continuously 24 hours per day except during water based activity. The treatment group will receive normal wristband with indicator showing steps count, distance, and calories. Meanwhile, the control group will receive Fitbit Zip with a display covered with adhesive tape and will not receive automatic feedback on the mobility from the device.

At the end of the intervention, all the data will be retrieved from the Fitbit Zip via Fitbit Connect software 2.0. On top of that, data on patients' demographic, types of operation, operative findings, length of hospital stay and postoperative complication will also be recorded in case report form.

Inclusion Criteria:

• Adult age >60 years old
• Patients electively scheduled for abdominal surgery includes upper gastro-intestinal surgery (subtotal gastrectomy, partial gastrectomy), colorectal surgery (hemicolectomy, anterior resection, sigmoidectomy, abdominal perineal resection), and hepatobiliary surgery ( pancreatectomy, cholecystectomy, hepatectomy)
• Able to provide informed consent

Exclusion Criteria:

• Cognitive impairment
• Neurological deficit which requires assistance in mobilization (e.g stroke, post limb amputation)
• Emergency surgery
• Prolonged ventilation >24 hours
• Prolonged stay in ICU >48 hours
• Lack of compliance to wearing wrist band
• Allergic to wristband