Andrew Miller: Why a bad sleep might be just as detrimental to our health as smoking or alcohol

“Where did you grow up?” my bright-eyed elderly patient asked, as I popped the IV into her innocent arm. “I don’t think he did,” mumbled the unhelpfully truthful nurse, smiling sweetly. Growing up is overrated. “Good for you,” slurred the patient just as the drugs reached her brainstem, rendering her unconscious. Being aware only has a temporary biological basis, inside our fragile brain. Anaesthesia contains no dreams — except during emergence, when true sleep might intervene. “Waking and dreaming are variations of the same basic brain state,” is how influential neuroscientist J. Allan Hobson put it. Dreams occur because the forebrain builds coherence, which is what it always does, in this case from chaotic REM activations. Last week I was in Sydney for board meetings, in company with the family. After a night of sensory overload outdoors at Circular Quay with hordes of incoherently merry Christmas party attendees, our worn-out, cranky seven-year-old needed a sleep-in, and so did I. And sleep she did, with the effortless ease jealous adults can only daydream about. Twelve hours later she remained cocooned, hair cascading over the pillows, limbs akimbo and eyelids occasionally flickering as she floated in the warm amnion of her dreams. In stark contrast, my prostate claxon had sounded before dawn and my ineffectual grabs at core sleep were pushed aside by the ragged agendas that constitute the portfolio of my petty adult burdens. I noticed a mild headache, possibly aggravated by the affectionate matrimonial pats occasionally received as rewards for my louder snores and snorts. I have a new smart watch; it’s much smarter than me anyway. Now lighter, with a longer battery life, they can comfortably collect accurate biometric data during sleep, proving again just how wrong I can be. I thought I was sleeping eight hours a night, but the laboratory validated watch is rarely recording more than six. Sleep is essential for all central nervous systems, even the C. elegans roundworm with its well-studied 302 neurons. Humans boast around 85 to 100 billion neurons, so not only do we have little excuse for forgetting the same person’s name at every Christmas party, it’s also hardly surprisingly that nightly physiological housekeeping is essential for our mental and physical health. During ninety-minute cycles of REM and non-REM sleep the brain is surprisingly active on a schedule of metabolic tasks, including increasing interstitial space by sixty percent to clear beta and tau amyloid in sticky glymph. Those are the proteins targeted in the agonisingly slow development of holy-grail dementia therapies. While we accept the idea that smoking, carrying extra weight, and diabetes are risk factors for multisystem disease, chronic sleep deprivation is an underappreciated problem that might be just as detrimental. Sleep’s importance is easily demonstrated by the severe symptoms that even short periods of denial can evoke. Emotional instability, hallucinations, marked cognitive impairment and involuntary microsleeps can start occurring after only 24 hours of awake time. All this is exaggerated in the developing mind of a child, where the raw numbers are staggering. Under two-year-olds make millions of new synaptic connections every second — a lot of that apparently related to shoving random items in their mouth. By the age of seven, synapses are being organised into neural topiary — there are still millions being made each minute, but many more are being pruned in a great cull as cerebral circuits, the freeways of the mind, are inscribed. We know that kids quickly become animals when they are hungry; in new environments; over-stimulated by Satan’s screens; on a sugar high, or tired. With such a complex nervous system, all this is hardly surprising, yet we often demand degrees of self-control from children that adults themselves rarely achieve under stress. We alleged grown-ups must also become much more sympathetic to our own need for proper sleep. All I want for Christmas is a nap after lunch, during which I might dream of being able, once more, to sleep like a seven-year-old.