You have probably heard of people who rise with the morning sun. But how about people who have already accomplished half of the day's tasks even before dawn?
No, we are not talking about shift workers or taxi drivers, but a breed of early risers who start their day as early as 4.30am - by choice.
While many of us are still drooling onto pillows, these extreme early birds have already ticked off items on their to-do list, such as running 10km, cleaning their home and clearing their e-mail.
They say such a lifestyle invigorates them and makes them feel productive and efficient. They also usually go to bed well before midnight.
Social media analyst Augustus Loi, 30, has a selfimposed weekday schedule that begins at 5am.
Before he goes into the office at 9am, he has already run a myriad of personal errands, such as doing housework, going to the gym or teaching himself something new - he is now teaching himself programming.
While his colleagues are blearily revving up their engines with coffee, he does not need a "slow ramp up" as he is already "wide awake".
He says: "I read that successful people wake up early. This is part of managing myself and seeing time as my resource."
Indeed, famous morning people include Apple chief executive Tim Cook, who is known to begin sending e-mail at 4.30am and hits the gym at around 5am, and Disney chief executive Bob Iger, who gets up at 4.30am every day and begins some heavy-duty multi- tasking. He exercises, reads the papers, listens to music, watches TV and reads e-mail all at the same time.
For those of us who have a deep attachment to our beds, the thought of getting up in the wee hours may inspire no small degree of fear and loathing.
But these "mind over mattress" people say that an early start energises them instead of making them feel tired.
Housewife Clarissa Choh, 39, wakes up by 5.30am every day, prepares breakfast for her three schoolgoing children, takes them to school and hits the Evolve MMA gym by 7.30am for a Brazilian jiu-jitsu class.
After the workout, she runs errands between 9 and 11am.
"By noon, I feel that I've accomplished many things," she says. "I'm much busier now as a full-time mother than when I was working, but I surprisingly don't feel as tired."
She used to own a clothing boutique.
Given the level of discipline required to be an early bird, it is no surprise that a lot of them are exercise junkies.
Yoga teacher Azmi Samdjaga, 43, has been waking up at 5.30am daily to practise yoga for the past 10 years because it "energises" him.
Marketing communications manager Darren Marc Tan, 30, gets up at 5am every day to run. On weekdays, he clocks 12km before heading to work. On weekends, he completes 18km.
"I concentrate better throughout the day. I am more alert and do work faster," he says.
It is not all about work productivity. Others have personal reasons for waking up early.
Commodities banker and restaurateur David Seow, 30, wakes up by 5am every Saturday to play golf with his father as the sport is "part of father-son bonding time".
Because one round of golf can take at least four hours, he says an early game usually concludes by lunchtime, which leaves him the rest of his Saturday afternoon to run errands and hang out with friends. In the evening, he helps out at Restaurant Labyrinth, which he co-founded with three others.
Retiree Winnie Tan, 61, is up by 4.30am every day and spends her first waking hour in prayer. The devout Catholic considers this a "happy sacrifice" of her sleeping time.
"I look forward to waking up for this special hour. I see it as a commitment I've made to God and I want to keep to what I've promised," she says.
Doctors and psychologists here say there is no conclusive scientific study that shows that an early riser performs better than a night owl or that early risers live longer.
Dr Yik Keng Yeong, a general practitioner, says it boils down to "personal philosophy".
"You either subscribe to the belief of being an early riser or you do not," he says, adding that he personally believes in the old adage "Early to bed and early to rise makes a man healthy, wealthy and wise".
Psychologist Daniel Koh of Insights Mind Centre says that brain repair takes place between midnight and 3am daily, so if a person is asleep during that window, he is getting quality sleep.
Since early risers tend to head to bed early, they are more likely to benefit from this brain-repair window.
Most importantly, the early risers are happy and proud of their time management.
Mr Loi says: "Some people think I'm a little extreme, but I don't feel stressed about keeping to this schedule. I feel that I'm in control of my time and I'm not rushing through my days."