As the COVID-19 pandemic drags on, sleep deprivation has become a cause for concern among some people 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.

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.