Celebrated on April 7 of every year since 1950, World Health Day spreads awareness about the importance of our health, and the many reasons why it’s so vital. Sponsored by organizations such as the WHO (World Health Organization), this year’s theme is “Our planet, our health”. This theme represents an array of topical modern-day health issues affecting the world at large, such as climate change, keeping cities liveable, making clean water accessible, reducing air pollution, and mitigating diseases like those spread by mosquitoes.

Since it’s a holiday devoted to making the world a healthier place to live in, one of the healthiest changes you can make to your daily routine is getting more sleep every night—after all, nearly a third of our lives is spent being asleep. Here are some pieces of advice recommended by the WHO for improving your sleep hygiene.

Don’t underestimate the stages of your sleep—each one counts!

In January 2004, the WHO met in Germany with 21 sleep experts from around the globe, to examine and review the long-term health consequences of chronic interrupted sleep before determining what exactly a “normal” night’s sleep consists of. One of the key topics in their findings concerns how sleep involves a variety of stages.

The first type of sleep normally experienced is NREM (non-rapid eye movement), where alpha waves associated with being awake start to fade. Brain activity begins to increase during the second stage (though without any eye movement), while the third stage (formerly split into a third and fourth stage), known as slow wave sleep (SWS), is when the brain falls into a deeper sleep and heart rate and brain activity slow down. These stages are important to remember, since adults sleep an average of seven to nine hours nightly, and slow wave sleep can start to dissipate once one reaches age 40—which can lead to frequent awakenings during the night.

Children younger than 5 need to sleep even longer than normal

If you’re a parent of a child in this age range, you'll want to pay attention to this one. This is because young children have different sleep habits than adults, therefore their sleep hygiene will involve more hours during the night. According to another WHO study from 2019, the range of sleep hours for children aged 3-4 should be 10 to 13 hours a night, meanwhile babies less than a year old are recommended to get as many as 16 (if between 4 and 11 months of age) or 17 hours of sleep (if between 0 and 3 months). To maximize sleep and health benefits, kids aged 2 to 4 should be getting a minimum of three hours of physical activity per day, while spending no more than one hour in front of a screen daily.

For adults, remember to keep your environment quiet and comfy

Certain sleep disorders such as sleep apnea, narcolepsy, and insomnia are ones adults can be vulnerable to, and can lead to a variety of health issues. Worse, a lack of sleep can have real-world consequences, such as difficulty concentrating, subpar work performance, psychological issues such as depression, and general fatigue.

One factor the WHO says can directly impact sleep continuity is external stimuli such as noise. Therefore, keeping your sleep environment as quiet and calm as possible can help prevent any short-term drowsiness you may feel during the day. Sleeping in a room that’s also dark and at a comfortable temperature can also help minimize potential sleep disturbances. In any case, the WHO recommends you get as high-quality of a sleep as possible, since it’s critical for our own well-being in the short, medium, and long-term.