Sleep complaints and unusual sleep durations have been found to increase the risk for coronary heart disease. One explanation states that insomnia and excess fatigue on final waking are predictive for myocardial infarction because they are part of a state of 'vital exhaustion'. Sleep complaints and sleep durations, however, are usually assessed with retrospective self-report procedures. Such procedures must be interpreted with reserve because in insomniacs, a consistent disparity in the perception of habitual and current sleep has been observed. This caused us to question whether this phenomenon is present in exhausted males also. Two approaches were used. The first one consisted of a retrospective assessment of subjective sleep characteristics, the second one of self-monitoring these sleep characteristics during 21 days. In the second week, subjects slept in a laboratory. No disparity was found in how exhausted males perceive their habitual and current sleep. It appeared that sleep quality is worse and sleep duration is shorter in exhausted males. They also feel more sleepy and take longer naps during the day, indicating that their daytime functioning is impaired. Sleeping in a laboratory reduced time asleep and midsleep wake. Sleep quality, however, was essentially the same as at home. These findings made us conclude that it is not the intrusion of nocturnal wake times per se but more likely the impaired daytime functioning which is the reason for exhausted males to complain about their sleep.