New research from the University of Pennsylvania School of Medicine in
Philadelphia, USA, has shown that people who sleep less than 5 hours a day have
impaired mental ability much similar to those who go without sleep for two or
three days continuously. The study that was published in the March issue of the
journal Sleep involved 48 participants divided into 4 groups. The first group
slept four hours a night for two weeks, the second group slept six hours a night
for two weeks, the third group slept eight hours a night for the same period and
the fourth group did not sleep at all for three consecutive days. The
participants were monitored to see that they were awake. Mental and
physiological tests were used every day to monitor how the participants were
coping with the little sleep. They also had to evaluate how tired they felt.
Researchers found that those who slept less than eight hours were slow to react,
less able to think clearly and struggled to perform simple memory tasks. The
impaired level of mental ability was similar to those who did not sleep at all.
participants who actually slept a few hours reported that they felt
less tired than those who were deprived of their sleep for a few days.
Researchers also indicated the different individuals needed different amounts of
sleep. In conclusion, lead author of the study Dr Hans van Dongen of the
University of Pennsylvania School of Medicine said that counter measures should
be worked out for people like pilots, trainee doctors, who are continuously
sleep deprived due to their work.