Sick of counting sheep while nursing a runny nose? You're not alone-most cold sufferers curse the night-time. But why does your already annoying cold suddenly feel like the end of the world when you're trying to doze off? We've got Dr. John W. Seibert, from the Vanderbilt Bill Wilkerson Center for Otolaryngology and Communication Sciences, and a couple more big brains to break down this nocturnal nuisance.

The offering plate's first contributor is your circadian rhythm. Ready for the all-night party, it boosts your already hyped-up immune system, causing inflammation and worsening your symptoms. Add in the hormone cortisol that drops at night (after peaking in the morning to reduce inflammation), and we've got a delightful cocktail spelling 'misery.'

Stacking up more misery points is your body's inability to drain post-nasal mucus when you lie down, which straps a rocket onto your journey to a broken sleep. Of course, daytime activities erratically juggle your attention, but the quiet solitude of night empowers you to get laser-focused on every symptom-hyper-observing your suffering can worsen your perceived condition.

So if you're flipping your pillow to find a cold side of relief, or worsening symptoms are cutting into your Beautyrest, don't soldier on; seek medical advice. Remember, common colds live for the drama at night but don't let them take away your crucial z's.