Two nights of bad sleep makes you feel four years older, study shows

A woman stifles a yawn as she looks out of the window during her commute.

Good quality sleep underpins our overall well being, including our cognitive performance, mood and long term cardiac health. Now, evidence shows that the quality and duration of our sleep also determines how young we feel. 

A study, conducted by researchers at Stockholm University, has found evidence to suggest that sleep directly influences how energetic (young) we feel. Similarly, poor quality sleep has been linked to feeling unenergetic (old).