I have often wondered why some people have no difficulty falling asleep on a plane or bus, maintaining their blissful slumber impervious to light, noise and movement, whereas others will be woken by the squeak of a mouse or a toilet flushing, and are highly sensitive to light and other disturbances. Unfortunately, I happen to be on the extreme end of the light sleeper spectrum and depend on being hermetically sealed with my eye mask and ear plugs, in a dark and quiet room, for any hope of falling and staying asleep.
This is highly inconvenient, especially living in a terraced house in the inner city, where noisy neighbours and frequent traffic are all part of the otherwise fantastic lifesyle. Without a doubt, if there was one thing I could change about myself it would be to become a heavy sleeper.
In a quest to overcome this trait, I’ve tried hypnotherapy, mindfulness meditation, listening to calm music, lavender drops, warm milk and reading until I’m exhausted. But the reality is, if it’s not dark and deathly quiet, I simply don’t fall asleep.
My annoying idiosyncrasy has also had unforeseen consequences. Like the time I went on holiday to Byron Bay and diligently packed my ear plugs and an unused eye mask which I’d squirreled away after a long haul flight. I awoke the first morning to find my face swollen with a pink allergic rash from the dye in the eye mask, which had mixed with my sweat during the hot humid night. I looked like a sick raccoon and spent the rest of the holiday on antihistamines and hiding behind oversized sunglasses. Not fun, or pretty.
But now I have the answer to the question I have pondered all my life. Scientists at the Harvard Medical School, led by neurologist Dr Jeffrey Ellenbogen, have discovered why some people’s brains are better than others at blocking out environmental stimuli during sleep. Ellenbogen and his team recorded the brainwaves of people who reported being heavy sleepers as they were subjected to different noises at increasing volumes. Ellenbogen paid particular attention to the patterns produced by the thalamus, the area of the brain that modulates incoming auditory and visual stimuli. He found that the number of pulses, or sleep spindles, produced by the thalamus varied among the sleepers. Those with the highest number of spindles were the heaviest sleepers and slept through more noises than those with fewer spindles.
Scientists are not sure why some people generate more sleep spindles than others, but they suspect it may be genetic. Dr Ellenbogen hopes that future research will lead to drugs or other therapies that can increase the number of sleep spindles so that light sleepers become better at blocking out external stimuli. I really hope they achieve their mission. Until then, my eye mask, ear plugs and the occasional sleeping pill will continue to be my lifesavers.