Physician’s Perspective

The Importance of A GOOD NIGHT’S SLEEP

… and Why You Might Not Be Getting One

By Fouzia Siddiqui, MD, FAAN

Getting a good night’s sleep is essential to helping the body and mind function optimally, and a continual lack of sleep can have significant health consequences. Unfortunately, sleep is often not taken seriously as a factor in good health, and many people regularly sacrifice hours of sleep in order to get through the demands of their busy schedules.

Approximately 50-70 million U.S. adults have a sleep disorder, the most common of which are obstructive sleep apnea and insomnia. In addition to interfering with daily activities (about 40% report unintentionally falling asleep during the day), sleep deprivation and sleep disorders can have substantial short-term and long-term effects on our brains.

Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a potentially serious sleep disorder in which breathing repeatedly stops and starts. The estimated prevalence rates of OSA have increased substantially over the last two decades, most likely due to our nation’s obesity epidemic. It is now estimated that 26% of adults in the U.S. between the ages of 30 and 70 years experience sleep apnea.

The physical effects of OSA on the body include hypertension, worsening diabetes, heart failure, heart disease, stroke and other vascular issues.

OSA also affects our brains, causing various sleep disturbances throughout the night that deprive the brain of oxygen and preclude the brain from getting to the restorative stages of sleep (deep sleep and REM sleep). As a result, people with OSA often experience symptoms such as short attention span, reduced short-term recall, irritability and mental exhaustion.

In terms of long-term effects, OSA can result in detrimental changes in brain matter and neurons, which can in turn lead to memory loss and alter neurotransmitter levels in the brain. In one study, researchers at the University of California, Los Angeles, compared the mammillary bodies— structures in the brain that are important in memory storage—of several adults suffering from sleep apnea with those of healthy people. They found that the mammillary bodies in the troubled sleepers were nearly 20% smaller than in their untroubled counterparts.

Furthermore, multiple studies have discovered a decrease in both gray and white matter in the brains of subjects with OSA. A neuroimaging study published in the journal Sleep found that participants with severe, untreated sleep apnea had a significant reduction in white matter fiber integrity in multiple brain areas, which was accompanied by impairments to cognition, mood and daytime alertness.

According to the American Academy of Sleep Medicine, a few studies have evaluated the effects of continuous positive airway pressure (CPAP) therapy on several subjects who had seen significant damage to their brain matter. After a year of CPAP treatment, these patients’ white matter was almost completely restored, while their gray matter saw substantial improvement after just three months. This is in line with other studies that have confirmed that CPAP treatment, when used regularly, can almost completely alleviate the symptoms and effects of sleep apnea.

Insomnia

Another very common sleep disorder in the developed world is insomnia, which involves difficulty falling asleep, staying asleep and not feeling refreshed during the daytime, and generally occurs at least three times a week for one month. Short-term insomnia is reported by about 30% of the population, and chronic insomnia by 10%.

According to a recent Johns Hopkins study, people with insomnia exhibited more neuronal excitability, which is defined as

the propensity of a neuron in the brain to generate an output signal from a given input signal. These findings indicate that “insomnia is not a nighttime disorder. It’s a 24-hour brain condition, like a light switch that is always on.” All this neural activity can have long-lasting effects on a person’s body, including poor short-term and long-term memory, reduced concentration, reduced attention span, mood irritability, and mental exhaustion. In short, insomnia leaves the brain exhausted and unable to perform the duties necessary to keep us happy, healthy and productive.

A study at the University of California, San Francisco, found an association between poor sleep quality and reduced gray matter in the frontal lobes of Gulf War veterans. The frontal lobe helps control important neurological processes, such as working task memory and executive function. The study revealed that poorer sleep quality, such as that among patients with chronic insomnia, is associated with reduced total cortical and regional frontal lobe matter volumes, resulting in cognitive deficits in attention, executive function and nonverbal memory.

Take Control of Your Sleep

With so many negative health effects of poor sleep quality on the body and brain, getting the recommended number of daily hours of sleep is essential. You can improve sleep quality by developing consistent routines at bedtime and creating a healthy sleep environment—for instance, by keeping the bedroom free of electronics and free of arguments; dimming lights; and keeping the room at a cool, comfortable temperature. If you have any symptoms of a sleep disorder, be sure to talk to your doctor about available treatments.