According to the experts, the amount of sleep needed every night in average is between seven and nine hours, to keep our minds alert and our bodies healthy. However, according to statistics, with the modern busy lifestyles many people aren't getting enough sleep.

According to the 2013 International Bedroom Poll, for instance, in the United States, half the population sleeps less than seven hours during the week. Many resort to catching up when circumstances allow, making up for the missing sleep hours. Whether it's napping during the day, or sleeping longer hours during the weekend, people try to find ways to get more rest.

But, according to experts, this catch-up can have its own impact on health. It could even be a sign of an underlying health problem when this catch-up becomes too much.

Sleeping in at weekends stems from the need to catch up on missing sleep hours during the week. According to Charles Czeisler, chief of the Division of Sleep and Circadian Disorders at the Brigham and Women's Hospital, in Boston, this is an attempt to recover from sleep deprivation during the work days.

However, Czeisler is not an advocate of sleeping late at the weekend, which he calls "sleep binging". The expert says that is a break from consistency and it can lead to further disruption of our sleep cycles.

According to experts, sleep takes place in alternating cycles of approximately 90-minutes, switching between Rapid Eye Movement (REM) and slow wave sleep (Non-REM sleep). The later time of awakening and the extra hours of sleep at the weekend can lead to confusion in the body when people return to their weekday routine. Czeisler defines this phenomenon as "social jet lag".

According to him, if you're waking up at 6 am on regular days and then at noon on a weekend day, that's the equivalent in time zones of Boston to Paris difference.

Making a habit of this, according to Czeisler, is not a healthy lifestyle to lead but rather it's a form of sleep bulimia with chronic binging. Such cycles can be disruptive to sleep integrity and people will miss vital moments in their sleep cycle, such as the most important REM cycles, the expert says.

Even worse, the "crash and burn" cycle many live by can lead to skimping on sleep and driving themselves to the point of exhaustion, and then crash, Czeisler added. This can have adverse health consequences and, for this reason, it's better to have the consistency of sleep.

On the other side, the daytime nap can do wonders to improve overall mood, performance and alertness and be for many a moment of relaxation.

U.S. National Sleep Foundation recommends naps of 20-30 minutes only, to avoid disruption of night sleep and grogginess and disruption of night sleep. But the desire to take a nap every day, even when having had a good night's sleep, particularly in countries where siestas are not the norm, could be a sign of something more serious.