This paper finds that shift work clearly affects sleep and wakefulness but
that there is very little known empirically about optimal sleep-wake patter
ns - except for the ones commonly used but not evaluated, for example, exte
nsion of morning sleep after night work, split sleep (main sleep + nap), na
p positioning and duration, delay of main sleep, full commitment to night w
ork (including bright light), phase advance and napping in relation to morn
ing work, and modification of sleep strategies depending on the speed and d
irection of rotation. Thus computer simulations of the efficacy of alternat
ive strategies must sometimes be used. The paper tries several such approac
hes and finds some possible ways of optimizing sleep. Still, the need for e
mpirical data is emphasized.