Does weekend nap compensate weekday overwake?

I read some literature regarding sleep recently. Sleep science has been studied for more than a century. However, there are many controversies about how to take good sleep.

Even the best duration of sleep in a day is still under argument. It is highly likely that less than six hours of sleep will do damage to your health. But, whether seven hours is adequate is uncertain. Some researchers claim eight hours sleep is required. The benefit and harm of oversleeping are also under discussion.

A recent study suggested the possibility that snoozing on the weekend can compensate the lack of sleep in the weekdays. After investigating a total of 38,000 Swedish people's sleep history, the researchers concluded that people taking one or two hours napping on weekend had the mortality as same as people with good regular sleep.

The Washington Post: Sleeping in on the weekends can compensate for lack of sleep during the week, study suggests

To be honest, I am skeptical of this outcome. I do not believe that only a few hours of extra-sleep can substitute regular sleep. I am scared that many businesspersons believe this result to reduce regular sleep on weekdays. Perhaps, the shortage of sleep cannot be a single reason for mortality. There is a hypothesis that the worst influence of shortened sleep is to cripple the immunology system in the body. Then, weekend snoozers may take some behaviors to activate their immunology systems, such as good cuisine and physical exercise.