As the coronavirus pandemic drags on, sleep deprivation has become a cause for concern among some people in Japan as they deal with lifestyle changes such as staying indoors or working from home.

Along with the rising stress, there has been a surge in the sale of sleep-promoting products while experts are advising people to modulate their sleep-wake cycles using various methods -- even basking in the morning sun to stimulate the secretion of a sleep-inducing hormone.

Photo shows Masaki Nakamura on Oct. 2, 2020. (Kyodo)

Masaki Nakamura, a doctor who operates a sleep and stress clinic in Minamiaoyama in Tokyo's Minato Ward, says he has seen a noticeable jump in patients since June after the government lifted the emergency declaration to combat the global health crisis late in the previous month.

"What stands out is the number of people visiting for the first time for anxiety or sleeplessness or repeat visitors with worsening conditions," said Nakamura.

Patients complain of pandemic-related stress. Some speak of how hard it is to get used to online work from home or the difficulty balancing work with private life. Others simply feel anxious about the future of their companies, Nakamura said.

One female patient, who, like her husband, is teleworking, told Nakamura she feels an extra burden now since she also cooks lunch for her partner, which only adds to her stress.

More than 20 percent of some 900 men and women in their 20s to 50s reported deteriorated sleep quality in an online survey by Well-Lab, a private concern established by doctors and other experts to offer information about women's health, according to findings it released in September.

Symptoms mentioned by many respondents included restless sleep, frequent waking at night, and fatigue even after sleep. Experts say prolonged sleeplessness can impair concentration, leading to mistakes on the job. In extreme cases, it may even result in depression.

Kenichi Kuriyama, head of the Department of Sleep-Wake Disorders at the National Center of Neurology and Psychiatry, said to sleep well, "resetting the biological clock is important." As preparation for a good night's sleep, "you should wake up at a fixed time every day and soak up the morning sun," he said.

The secretion of the hormone melatonin, which promotes healthy sleep, begins in the human body about 14 hours after the first exposure to light following waking. So if a person soaks up the sun at 7 a.m., melatonin production starts at around 9 p.m. When the secretion increases to a certain level, says Kuriyama, sleep comes on naturally.

But as the daily sleep-wake cycle is adjusted by an internal body clock that is slightly longer than 24 hours, a small time discrepancy emerges. Thus, resetting the body's internal clock in the morning is necessary for regular sleep.

People have trouble falling asleep if their brains are agitated or are in a state of tension. To relax, experts recommend taking a lukewarm bath a couple of hours before going to bed or using a steamed towel or hot compress to warm the eyes. Other recommendations include stretching and performing yoga.

"You cannot sleep if you try your best to sleep," said Kuriyama. He suggests trying various methods before hitting the hay.

Indeed, demand has been on the rise for sleep-inducing products and other items such as bathwater additives for relaxation.

As of Oct. 19, monthly sales of miscellaneous sleep-related goods at the Loft retail chain based in Tokyo, including a fragrant mist spray for pillows, grew by 40 to 60 percent compared with the same period last year.