I should’ve won an Oscar for the cool-as-a-cucumber work persona I portrayed back in my coffee-slinging days. Out of necessity, I had mastered the art of the even keel. But on the inside, I felt just the opposite. I was averaging three to four hours of sleep a night, arriving to work at 4:30 in the morning and teetering through my shifts like a lunatic zombie. During those days of chronic sleep deprivation, the slightest provocations—snippy customers, malfunctioning equipment, spilt milk (literally)—brought on uncharacteristic tidal waves of anxiety, sadness, desperation, and fury. It was as if the volume on my feelings dial had been turned up to eleven and the knob was broken off.
I have since recovered from this descent into zombie melodramatics and now enjoy regular sleep patterns, but the experience left me wondering about the havoc that sleep deprivation wreaks on our emotions. Why do we get so punchy and sensitive when we don’t get enough sleep? Scientists have been grappling with this very question for years, and in 2007, a new culprit behind all the crazy arrived on the scene.
The Amygdala: Where Feelings Are Born
This small, almond-shape structure in the temporal lobe helps to process our emotions. Most notably, it’s linked to anxiety and fear responses, meaning that when you see something distressful take place—like an angry, overly caffeinated customer lunging toward you screaming “Where’s my half ‘n’ half?!!”—the amygdala is responsible for interpreting it as such and sends out signals to the rest of your brain and body. (Cue quickened heartbeat, shortness of breath, and an overwhelming desire to pour all available creamer in the building down the drain.)
In a study published in Current Biology in 2007, researchers observed the neural activity of twenty-six participants as they were shown increasingly gory images. Fourteen of them had been awake for thirty-five hours straight; twelve had slept normally. Much to the surprise of the researchers, the MRI scans showed that amygdala in the sleep-deprived group was a whopping 60 percent more reactive to the pictures than in the normal-sleep group, indicating significantly higher levels of distress.
Also surprising was the fact that the amygdala in the sleep-deprived group had lower connectivity with the medial prefrontal-cortex, which functions to ensure that our emotional responses are contextually appropriate. In other words, it tells the amygdala to get a grip when it’s advocating for an unbridled fit of hysterics over spilt milk at the condiment counter. When well-rested, the more primal amygdala relents to the cortex’s refined wisdom; when sleep-deprived, it goes rogue.
In the long-term, a rogue amygdala may have ominous implications for mental and emotional well-being. Chronic depression and bipolar disorder are a few of the conditions linked with an overactive or abnormal amygdala.
I’ll never fully understand how I mustered remote unflappability while Amygdalapalooza was taking place in my feeble, tired brain, but I take a small amount of comfort in knowing that science can explain at least some of the emotional maelstrom that swept over me. The good news is that normal emotional balance can usually be restored with a good night’s rest. So the next time you feel compelled to bawl at the sight of undercooked spaghetti, take stock of your sleep patterns. A little shut-eye will do some good.
