We've all got that one mate who seems perfectly fine on just a few hours of sleep while we feel like a zombie if we don't get our recommended 7-8 hours. Turns out, it's not just because they're a mutant (although, technically, they could be).

Here's the deal: If you're regularly clocking in less than 5 hours of sleep and still not showing signs of sleep deprivation like drowsiness, forgetfulness, and increased urge to steal all the office stationery - you might be one of the "chosen" few who have what's called Short Sleep Syndrome (SSS). Snazzy name, right?

Now, before you rejoice and think, "Awesome! More time for Netflix," understand that SSS is a legitimate medical condition believed to be caused by a rare gene mutation. People with SSS don't need naps or to cram in extra sleep on weekends and they still rock at work or school with only their piddly amount of sleep. Researchers think genetics plays a big part in it.

These lucky folks (or maybe it's just us envious zombies speaking) may have a particular mutation of the ADRB1 gene. This wonderful francium of a genetic tweak is linked with shorter sleep cycles and a buttload of β1-adrenergic receptors. These receptors are handy side-kicks regulating body functions during the circadian (wake-sleep) schedule. In essence, they’ve basically got a super-efficient body clock.

On the flip side, if you fall into the bigger masses of us poor, sleep-deprived souls, it's probably due to factors such as consuming enough caffeine to stun a horse, or a love-hate relationship with your pillow. Common causes can include insomnia, narcolepsy, chronically singing the 'I can't sleep' blues, or intake of too much caffeine or alcohol.

While occasional insomnia falls into the annoying-but-no-big-deal category, if it's more of a frequent flyer, it might be time to skedaddle to a healthcare provider. Often, little tweaks in your sleep hygiene like religiously sticking to a sleep schedule or avoiding caffeine late in the day, can help tame the sleepless beast within.

Just remember, whether you're a coffee-guzzling sleep zombie or a marvel genetic abnormality able to do with less sleep, maintaining a balanced, healthy lifestyle is the key. Anything out of the ordinary, whether it's chronic sleep deprivation or abnormally less need for sleep, should be checked out by a healthcare trooper. Because, well, you're worth it, right?