People around the globe marked World Sleep Day on Friday, an annual event that serves as a reminder of the importance of sleep to one's well-being and health.

In a pre-recorded interview broadcast on RTHK's Hong Kong Today programme, Julia Sun, a clinical psychologist at the Chinese University's Department of Psychiatry, said people should not underestimate the importance of a good night's sleep.

"Sleep is really important and it is related to the physical and mental well-being. Physically, chronic sleep depravation will lead to reduced immune function and hormonal imbalance. And also we can see that when people sleep less, they tend to gain more weight. Sleep depravation is also linked to increased cardiovascular risk," Sun said.

"In terms of mental well-being, insomnia, or sleeping less, leads to increased irritability... it also leads to more mood swings and also difficulty in managing stress."

Sun recommended that people get into a routine before bed, to ensure a good night's sleep.

"I think that regularity is important - try to have a regular sleep-wake schedule no matter in weekdays or weekends... try to limit the screen use before sleep, for example like 15 to 30 minutes before bedtime. And also you can dim your light before you go to sleep."