Inactivity for most people (non-athletes) will result in decreased muscle strength at a rate of one to three percent per day, with noticeable strength loss occurring after about two and a half to three weeks. If you are sick or completely immobilized (think bed rest), muscle strength can decrease by 50 percent in just three weeks.
Admission to hospital often causes physical deterioration especially for elderly patients, and muscle deconditioning begins within 2 days. Baseline strength reducing by up to 20% in 1 week, which is the equivalent of 10 years of normal ageing.
Muscle strength loss impacts on a person’s ability to do normal activities of daily living. It unfortunately takes at least twice the amount of time to build muscle back up as it does to lose it.