Although sleep deprivation can have a significant adverse effect on our daytime functioning, it is not a “one size fits all” phenomenon. Recent research has shown that younger and longer sleepers (eight or more hours per night) are more sensitive to the effects of sleep loss. A recent study involving older people (on average, age 58) found that their performance after sleep deprivation was not significantly altered and another study found that older people (on average, 68 years) appear to need less sleep than younger people (on average, 22 years).
Besides age, there are significant “trait-like” differences in individual response to sleep loss. One study discovered that while some subjects showed significant impairment in daytime functioning after 36 hours of sleep deprivation, other subjects exhibited minimal impairment. In addition, because the study involved a group of young, healthy adults, the researchers believe that individual differences in response to sleep deprivation in the real world population of young, middle age, and older adults would be even greater.
These recent findings demonstrate that the effects of sleep deprivation are not a "one size fits all" phenomenon: just as people have different sleep needs, their responses to sleep loss vary significantly.
It turns out that the effects of sleep deprivation are dependent upon whether a person has experienced partial or total sleep loss; over how many days the loss occurs; whether recovery sleep is possible; and the circumstances under which the loss takes place. Sleep loss in laboratory studies on sleep deprivation, typically involving only four hours of sleep a night with no recovery sleep allowed for a week or even longer, is far more severe than the more modest sleep losses most people struggle with in daily life. And sleep loss does not have the same negative effects if the person is motivated to cope with it; for example, if he or she dealing with a crisis, on call as a doctor, being paid to work long shifts with little sleep, or caring for a newborn. It also helps if the loss occurs under positive circumstances such as a vacation or social event. Of course, because of the stress of lab experiments, it is not clear if stress or sleep loss produces the impairment, but real-life sleep loss can occur as a result of stress. In fact, stress is a typical cause of sleep problems so we don't know yet if the performance decrements after sleep loss are due to sleep loss itself or the stress that causes the sleep loss.
The bottom line: sleep loss does not always have significant detrimental effects on daytime functioning.
Dr. Gregg D. Jacobs, www.cbtforinsomnia.com/mh