Staying in bed leads to deconditioning that can largely be prevented by physical activity (1). In the context of ERPs, being out of bed on POD0 and POD1 are independent predictors of shorter hospital stay (2). There is little available evidence to suggest what amount of mobilization improves outcomes. Patients are helped to be out of bed after transfer to the ward on POD0. The next day, they are helped to eat all meals out of bed and to walk the length of the hall at least three times.
For more information, see Chapter 14: Early Nutrition and Early Mobilization: Why They Are Important and How to Make it Happen in The SAGES / ERAS® Society Manual of Enhanced Recovery Programs for Gastrointestinal Surgery
References
1. Convertino VA. Cardiovascular consequences of bed rest: effect on maximal oxygen uptake. Med Sci Sports Exerc. 1997 Feb;29(2):191-6.
2. Maessen J, Dejong CH, Hausel J, Nygren J, Lassen K, Andersen J, Kessels AG, Revhaug A, Kehlet H, Ljungqvist O, Fearon KC, von Meyenfeldt MF. A protocol is not enough to implement an enhanced recovery programme for colorectal resection. Br J Surg. 2007 Feb;94(2):224-31.