On the occasion of World Sleep Day, a sleep-in-forest competition kicked off on Saturday at Dongping National Forest Park on Shanghai's Chongming Island, with a first batch of 50 participants immersed in fresh air and greenery for a good sleep and a cash prize.

The competition will be regularly held from 9 am to 7:20 pm on Saturdays through April 26, as well as on May 2 and 3. Competitors' sleep conditions will be objectively recorded by professional sleep monitoring devices, which will comprehensively evaluate each one's sleep quality and decide the winners. Data metrics include sleep latency, total sleep duration, deep sleep percentage and sleep continuity.

The organizers disclosed that the monitoring equipment would collect real-time data on participants' heart rates, sleep duration and other information, which will be displayed simultaneously on a large screen on-site.

At every competitive event, the participant with the highest sleep score can win a cash prize of 3,000 yuan ($435), while the contestant who falls asleep the fastest can earn 2,000 yuan. All other participants who follow the rules and make it to the end would share a prize pool of 10,000 yuan, according to the organizers.

Aiming to free urban residents from their daily hustle and bustle, the contest is extensively open to healthy individuals aged 18 to 50. Falling asleep is not mandatory for the competition. Participants are allowed restful activities such as simply closing their eyes or lying still.

Throughout the entire event, participants should remain lying down on the provided standard mattress. They are allowed to turn over, but no part of the body should extend beyond one-third of the mattress' surface area. Significant movements such as sitting up, standing or leaving the bed to visit a restroom will be seen as the end of their challenge.

Conversation or other disturbing behavior with others, eating or drinking — except for water — are not allowed during the competition. Electronic devices such as cellphones and tablets, as well as other entertainment devices, are also not allowed.

The competition has seen active registration and gained unexpected popularity on social media platforms. Sticking to the idea of "take a lung cleanse and get some good sleep", the organizers hope to offer participants a unique sleep experience at a national forest park, leveraging the power of nature to offer them physical and mental relaxation.

Chongming is China's third-largest island and is on its way to becoming a world-class eco-friendly island. With 20 percent of Shanghai's municipal area, it boasts the city's best air quality, largest green space, and richest biodiversity, and supports approximately 28 percent of the city's forest resources.

wangxin2@chinadaily.com.cn