Dr. Guy Leschziner: Pursuing perfect sleep worsens insomnia

Around 30% of adults will experience insomnia in a given year and ~10% develop chronic insomnia. The most effective first‑line treatment is Cognitive Behavioral Therapy for Insomnia (CBT‑I), which targets both conscious anxiety about sleep and unconscious conditioning that links bed with being awake. Techniques include sleep restriction (temporarily limiting time in bed to roughly the amount you’re actually sleeping) and stimulus control (only using bed for sleep and sex). Properly delivered, CBT‑I significantly improves sleep in up to about 80% of chronic insomniacs.

Sleep naturally fluctuates and there is no single “perfect” template; genetics, age, and life context matter. Overemphasis on rigid targets (e.g. exactly eight hours) and constant monitoring (especially via trackers) can heighten anxiety, weaken the association between bed and sleep, and actually precipitate or worsen insomnia. For many people with insomnia, putting away the tracker and reducing catastrophic thinking about sleep is more therapeutic than more data.

Sleep switches us off from the environment and makes us vulnerable, yet it has been conserved across species; some animals even evolved to sleep with half their brain at a time just to keep doing it. Sleep supports immune function, cardiovascular health, glucose regulation, pain perception, and mental health. Deep slow‑wave sleep appears particularly tied to restoration, and likely plays a role in metabolic 'housekeeping' in the brain, including clearance of proteins like beta‑amyloid that are linked to Alzheimer’s disease.

Every cell carries a roughly 24‑hour clock coordinated by a master clock in the hypothalamus, strongly influenced by light, especially blue light via specialized retinal cells. Evening screen use doesn’t usually cause instant insomnia via blue light alone, but chronically pushes the body clock later while social obligations still demand early wake‑times, creating chronic sleep deprivation. Pre‑industrial societies show far less insomnia and different, more flexible sleep patterns, highlighting the role of contemporary culture and schedules.

Even a single night of sleep loss can dramatically increase calorie intake, alter appetite/satiety hormones, and bias people toward higher‑sugar, more energy‑dense foods. Chronic short sleep is associated with greater weight gain over years, impaired glucose tolerance, and increased diabetes risk. On the brain side, sleep loss leads to local “micro‑sleeps” in cortical areas, degraded cognition, and heightened emotional reactivity, complicating treatment of anxiety and depression.