The patient should usually keep the sleep diary for two to three weeks. Items one to three on the sample diary record total sleep time and items four to seven record time spent in bed.
You should divide the average sleep time by the average time spent in bed for each seven-day period. Multiply the answer by 100 to get an estimate of sleep efficiency. The aim is to increase sleep efficiency to as close to 100% as possible by minimising the amount of time spent in bed trying to fall asleep and maximising the time spent in bed actually sleeping.