The long weekend lie-in may be a tempting prospect, but it doesn't appear to make up for all the damage caused a lack of shut-eye during the week.
While it does reduce sleepiness, stress and inflammation within the body, it won't help restore the ability to concentrate, American researchers have found.
Research has shown that even a few days of lost sleep can have adverse effects, 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 could partially explain why sleeping less negatively affects health in other ways and shortens the lifespan.
Though many people believe they can make up sleep lost during the week by sleeping more on the weekend, it’s unknown whether this ‘recovery’ sleep can adequately reverse these adverse effects.
To help answer this question, researchers led by Alexandros Vgontzas of the Penn State University College of Medicine, in the U.S., placed 30 volunteers on a sleep schedule that mimicked a sleep-restricted week, followed by a weekend with extra ‘recovery’ sleep.
At various points during this schedule, the researchers assessed the volunteers’ health and performance using a variety of different tests.
The researchers found that the volunteers’ sleepiness increased significantly after sleep restriction, but returned to baseline after recovery sleep. 
Levels of a molecule in blood that’s a marker for the amount of inflammation present in the body increased significantly during sleep restriction, but returned to normal after recovery.
Levels of a hormone that’s a marker of stress didn’t change during sleep restriction, but were significantly lower after recovery.
However, the volunteers’ measures on a performance test that assessed their ability to pay attention deteriorated significantly after sleep restriction and did not improve after recovery. 
This last result suggests that ‘recovery’ sleep over just a single weekend may not reverse all the effects of sleep lost during the week.
The study is entitled ‘The Effects of Recovery Sleep After One Workweek of Mild Sleep Restriction on Interleukin-6 and Cortisol Secretion and Daytime Sleepiness and Performance’. 
It appears in the American Journal of Physiology-Endocrinology and Metabolism, published by the American Physiological Society.