A new study suggests that extreme early risers – people who are willingly up by 5.30am – may not just be restricted to a handful of tech CEOs and your annoying cat. Around one in 300 people tracked over nearly 10 years had naturally early awake times, which may not sound that common, but is perhaps unthinkable for anyone who struggles to wake up at 8am.

One of the authors, Louis Ptáček, a professor of neurology at the University of California San Francisco, has been interested in extreme early risers for 20 years, after meeting a woman who would wake at 1 or 2am. He said that it made her miserable and lonely. “She grew depressed,” reports the Atlantic. “Sometimes, she would vacuum at 4am just to fill the time.”

For others, those early hours are cherished, filled with self-improving activities such as exercise and meditation. The schedule of the actor Mark Wahlberg created much excitement online last year; he claims to rise at 2.30am to pray, then exercise. In an interview earlier this year the singer Belinda Carlisle revealed herself to be an “extreme lark”: “I get up at 4am, have a coffee, then put on my Audible app and listen to a great spiritual teacher.”

At the 24-hour PureGym chain, says CEO Humphrey Cobbold: “We’ll get 50 to 60 people in between about 2am and 6am.” Some will be shift workers, not necessarily natural early birds, but many will have arranged an earlier start to their day which means they can leave work earlier. “They’re typically people who work in busy offices. They work out, grab a breakfast and are at their desk by 7am. People organise their days around that sort of schedule if it suits them.”

Anything past 6am “is a lie-in”, says Erica Wolfe-Murray, a business consultant and author of Simple Tips Smart Ideas. She wakes around 4.45am. “I can get so much done, I have huge clarity of thought and my book was largely written in bed from 4.30am,” she says. “I’d do two hours’ writing, then get up and go to circuit training, or in summer go for a walk.”

For Amir Khan, a GP who also appears on the Channel 5 show GPs: Behind Closed Doors, his day begins at 4.50am. He does a six- to nine-mile run, enjoying the peace of no traffic and few other people. Instead, he looks out for wildlife. “If it’s later in the year, I’ll see foxes and owls. At this time of year I see rabbits and deer, hedgehogs and badgers. It’s a lovely time of the day and it feels like it’s all yours – it’s special.”