If you lack this, you can feel much older

Lack of sleep makes you old

Scientists conducted two different studies to find out how important sleep is. Initially, 429 people were asked once a day how old they felt on a scale of 12 to 120 years. Their answers were compared to sleep data collected over a 30-day period.

The researchers found that increased fatigue and an increased number of sleep-deprived days over a 30-day period were associated with a tendency to feel older than your actual age.

The less self-reported sleep, the greater the impact on a person's perception of age.

Conversely, participants who got enough sleep felt much younger than they actually were.

In the second study, which included 186 people aged 18 to 46, scientists looked at how optimal sleep and restricted sleep affected how older participants felt.

Optimal sleep was defined as two consecutive days of nine hours of sleep per night, while limited sleep was defined as two consecutive days of only four hours of sleep per night.

The study lasted a total of one week and was conducted in participants' homes. All test subjects had to keep a sleep diary and were also equipped with a so-called actigraph, which records sleep and movement patterns. On the last two days of the study, participants were asked to follow the optimal sleep instructions or the restricted sleep instructions. After that, laboratory tests were performed on everyone.