Scientists say a decent diet and exercise program might make you feel young, but sleep may be the key.
A new study found that seven or nine hours of sleep makes you feel younger.
According to Stockholm University experts, sleeping fewer than eight hours a night can make you feel ten years older.
Youth is more than a feeling. The Sun reports that feeling young improves health as research shows.
Feeling younger is connected to a longer, healthier life expectancy and a younger brain.
Leonie Balter, Stockholm University Department of Psychology researcher, said: "Since sleep is essential for brain function and overall well-being, we decided to test whether sleep holds any secrets to preserving a youthful sense of age."
"While previous literature has shown that feeling older is associated with worse sleep quality, our data indicate that sleep may be more important for subjective age than the other way around," researchers wrote in Proceedings of the Royal Society B: Biological Sciences.