How long will it take for your muscles you built to start to atrophy and lose muscle?

Few weeks. How long for toned muscles to atrophy from disuse? Evidence indicates two weeks of strict bedrest causes significant muscle weakness & dysfunction; which begets further weakness & escalating disuse. Degree of weakness is likely dependent upon baseline muscle mass/tone.This phenomenon seems explanatory for weak/spastic/pained muscles contributory to onset of fibromyalgia after a serious illness. .