India, April 14 -- Do you wake up in the middle of the night? 3 am wake-ups may draw gasps if you believe in superstitious, supernatural theories. But there's nothing unnatural about it. In fact, there's a real, scientific reason behind why you wake up. Your biological rhythm is at play, and it can be attributed to diurnal variation.ALSO READ: Sleeping late every night? Study says poor sleep makes your brain age faster

Dr Amir Khan, a UK-based NHS general practitioner, explained in the No Appointment Needed Podcast episode dated April 14, why you may keep waking up at 3 AM and how cortisol plays a role. While this is a natural process, one lifestyle habit can make you more prone to late-night wakefulness.

Waking up at 3 AM is not myster...