Weekend lie-in reduces tiredness, tension and soreness within the body, but does not help in restoring concentration, according to researchers from Penn State University. The study was led by Alexandros Vgontzas.

According to the Daily Mail, researchers found that even if a person lost a few days of sleep, he/she faced unpleasant consequences including increased daytime sleepiness, worsened daytime performance, an increase in molecules that are a sign of inflammation in the body and impaired blood sugar regulation.

Increased inflammation and impaired blood sugar regulation partially indicates the negative effects of sleeping less.

This study was basically conducted to find out whether the 'recovery' sleep during the weekends can effectively reverse these unfavourable effects.

The researchers arrived at the conclusion after introducing 30 volunteers to a sleep schedule that imitated a sleep-restricted week and followed by a weekend with 'recovery' sleep, Newsroom America reported.

At various stages of the schedule, researchers analysed the volunteers' health and performance using several different tests. They found that the volunteers' drowsiness and levels of molecules increased considerably after sleep restriction, but returned to normal levels after recovery sleep.

Plus, the levels of hormone (a marker of stress) remained the same during sleep restriction but decreased drastically after the recovery sleep.

However, the volunteers' performance on tests conducted to study their concentration ability deteriorated radically after sleep restriction but did not improve after recovery.

This study suggests that 'recovery' sleep over a weekend does not overturn all the bad effects of sleep lost during the week.

The study 'The Effects of Recovery Sleep after One Workweek of Mild Sleep Restriction on Interleukin-6 and Cortisol Secretion and Daytime Sleepiness and Performance,' appears in the American Journal of Physiology-Endocrinology and Metabolism.