For years now, I've gotten up between 3:45 and 5 a.m. purely for logistical reasons, begrudgingly starting my day trying to get my blurry eyes to focus on my coffee. And the idea that an early morning is synonymous with success is incredibly pervasive--people repeatedly point out with the clear intention of emulation that leaders like Tim Cook get up well before the sun.

To all that, I'll argue: Getting up early might not be the secret to success we've all been told it is.

The Basics of Circadian Rhythm

People sleep and are awake based on a natural cycle you've probably heard of--the circadian rhythm. This rhythm is controlled by the hypothalamus in the brain, but it's influenced to a large degree by external factors. The biggest cue for the body is light, but other elements, like temperature, factor in, too.

So in a perfect world for most individuals, the sun would be a natural alarm clock, and work would happen about two hours after our nearest star lifted over the eastern horizon. That's how things worked for centuries before technological advances like the light bulb messed with it all.

When the Circadian Rhythm Goes Wrong

Now, this would make 4 a.m. mornings hard enough for plenty of leaders and workers, since 4 a.m. and the sunrise simply aren't aligned in most areas of the world for much of the year.

But it gets worse.

Some people also have honest-to-goodness circadian rhythm disorders. The most common, found in about 10 percent of people who complain of chronic insomnia, is delayed sleep-wake phase. With this condition, a person's natural body clock is set so that they fall asleep two or more hours later than most people do, and they get up later in the morning as a result. These "night owls" sleep perfectly fine otherwise, with no real problems getting quality rest.

Then you can have irregular sleep-wake rhythm disorder, where your rhythm is so disorganized you don't really have a pattern at all and just pretty much nap whenever you need to. There's also non-24-hour sleep-wake rhythm, where your rhythm shifts a little bit later every day in a long cycle.

And of course, there is advanced sleep-wake rhythm, where you get up hours before others do. While not everyone who gets up at 4 a.m. has this condition, a naturally earlier clock means that these early birds don't bat an eye at the idea that work starts long before the rooster crows. They naturally can fit the cultural demand to start as soon as possible.

Get Creative Instead of Feeling Guilty or Pointing Fingers

The big picture is, when people insist on the 4 a.m. morning, they're assuming that everyone works under the same biological script, and that changing that script is simply a matter of willpower. But this simply isn't true.

Yes, you can shift your schedule a little and use options like light lamps or oral melatonin as therapy to trick your brain. But variations in sleep scripts are real, and professionals believe that at least some circadian disorders might have a genetic component. That means you shouldn't hold it against yourself or anyone else if those therapies aren't effective enough.

People don't achieve early schedules based on mechanical or arbitrary cultural clocks. They achieve it based on biological ones, and rest and productivity are always in a yin-yang relationship, no matter where your clock setting might be. That means that, particularly now, in an age where flexible scheduling and gig-style jobs are commonplace, it's time to put to rest the idea that 4 a.m. wins.

Instead, get creative to accommodate varying schedule needs, and then achieve your best productivity by getting up whenever you darn well feel like it.