Diving into sleep Evolution, dreams and aging

I have been battling sleep issues lately, and as I look for ways to improve my situation, I find myself being drawn into a broader exploration of the topic. It’s interesting stuff, and I find it easy to understand why people devote entire careers to their studies. I am also humbled by realizing how little I know about a function that, in theory, should comprise roughly a third of our lives.

I’m finding that sleep is not merely a restorative state of inactivity but a dynamic process essential for survival and adaptation. Across the evolutionary timeline, sleep has promoted cognitive function, memory consolidation, and the socially (and professionally) essential function of emotional regulation.

The factoid that hooked me is an evolutionary trait known as “unihemispheric sleep.” In short, many species, birds and sea mammals in particular, are known to allow one hemisphere of the brain to sleep while the other remains awake. It’s an adaptation that allows dolphins to rest half of the brain while the other remains active enough to swim, surface for air, and remain aware of their surroundings. It’s not hard to imagine how that ability would benefit species under constant threat from predators, but I suspect that I may have employed similar tactics in budget hearings and lengthy church services.

I am also discovering the vicious effects of stress on sleep cycles. When conflict and sensory overload define our days, our active minds work against us, triggering hyperarousal and intrusive thoughts that disrupt our delicate balance of sleep. As the psychological toll of stress wreaks havoc on our sleep patterns, our lack of sleep impacts the following day, resulting in inattention and emotional volatility that, in turn, results in additional stress.

Our patterns of sleep, or “sleep architecture,” center around dreaming but are addressed separately from the more tantalizing topic of dream content. The subject matter of dreams has been approached from a decidedly less scientific point of view, ranging from the ponderings of ancient philosophers to notions of dimensional travel embraced by the late-night radio crowd.

The content of our dreams is influenced by a combination of factors, including our experiences, emotions, memories, and subconscious thoughts. Dreams often reflect our daily activities, concerns, preoccupations, and unresolved conflicts or desires. Additionally, physiological processes, including increased brain activity and neurotransmitter release, may contribute to the imagery and themes present in our dreams.

Independent of the subject matter, the occurrence of dreams (and their absence) plays a defining role in identifying the normative sleep architecture that is found to be restful and restorative. I’ll spare you the barrage of abbreviations and acronyms, but the oversimplified view is that the stages of rapid eye movement sleep (REM) and the deeper non-rapid eye movement sleep (NREM) are cyclical, and those cycles become progressively longer throughout the night.

Independently, the latter stages of NREM are characterized by slow brain waves (delta waves) and have been associated with restorative processes of tissue repair, hormonal activity, and another fascinating function, memory consolidation. REM sleep, on the other hand, is believed to play a role in emotional regulation and learning. The formula for restful and restorative sleep is finding the optimum balance and sequence of REM and NREM within the allotted time. I’ll go out on a limb here and predict that the person who figures out how to replicate the ideal pattern within a shorter period of time will become extremely wealthy.

With that 30,000-foot view, I am also attempting to understand how the progression of age can affect sleep. Influenced by physiological, psychological, and environmental factors, older adults are known to have an increased susceptibility to sleep disorders. Insomnia, sleep apnea, and restless leg syndrome are common disturbances that afflict those of us who are old enough to remember Nixon’s Cabinet and “Lancelot Link.” Those common disturbances alone can compromise our quality of life and overall health.

More serious issues, like chronic pain, respiratory disorders, neurological conditions, hormonal changes, gastrointestinal disturbances, and cardiovascular diseases, can also significantly impact sleep. If our assortment of maladies doesn’t keep us awake, the medications used to manage those conditions may also contribute to sleep disturbances in older adults.

My goal is to improve my situation with understanding rather than pharmaceuticals, and the best tip I have found so far is that periods of restlessness need not result in “insomnia anxiety.” While it’s not a replacement for the benefits of sleep, research has shown that quiet, peaceful wakefulness also has restorative value and should be positively embraced.