“I don’t sleep well and I’m exhausted” were her main complaints that day in the office. I then asked her, “What does an average 24-hour day look like for you?” She proceeded to describe her work as a janitor from 6 PM until 12:30 AM, sleeping from 1 AM until 6 AM, getting up to take her children to school, and then going to a second part-time job from 7 AM until 12 PM. After returning home from her second job, she does home errands and cooks, then picks up her children from school. She feeds them dinner before heading to her main job.  After getting a peek into a typical day of my patient’s life, and looking at her sleep study, it was clear that she had more than one sleep problem. Yes, she snored and had a crowded airway and indeed was found to have mild obstructive sleep apnea. Yes, she was under constant stress and sometimes had trouble falling asleep. But her biggest sleep disorder was the one that was eclipsing them all—insufficient sleep.

We now know that nutrition, exercise, and sleep are the three key components, or pillars, to living a healthy life and reducing the risk of poor performance and disease. 15 years ago the consequences of chronic insufficient sleep were not well-established, whereas today physicians and the general public are much more attuned to the potential consequences of sleep deprivation.  In the latest issue of SLEEP (Watson, NF et al., Recommended amount of sleep for a healthy adult: a joint consensus statement of the American Academy of Sleep Medicine and Sleep Research Society. SLEEP 2015; 38(6):843–844), experts in Sleep Medicine published their consensus statement on the desired sleep duration for adults ages 18-60. After reviewing 5314 scientific articles on the association between sleep duration and health, they came to the following conclusions:

  • “Sleeping less than 7 hours per night on a regular basis is associated with adverse health outcomes, including weight gain and obesity, diabetes, hypertension, heart disease and stroke, depression, and increased risk of death. Sleeping less than 7 hours per night is also associated with impaired immune function, increased pain, impaired performance, increased errors, and greater risk of accidents.
  • Sleeping more than 9 hours per night on a regular basis may be appropriate for young adults, individuals recovering from sleep debt, and individuals with illnesses. For others, it is uncertain whether sleeping more than 9 hours per night is associated with health risk.
  • People concerned they are sleeping too little or too much should consult their healthcare provider.”

Although wanting eight hours of sleep at night is a laudable goal, eight hours is not what everyone needs, and even 7 hours, as recommended above, may be hard to attain due to employment, home responsibilities, and other factors beyond our control. One of the treatment challenges of improving sleep duration is that by putting pressure on ourselves to sleep enough, we may inadvertently trigger anxiety about sleep and therefore push sleep further away.  In an achievement-oriented world, we easily fall into the trap of treating sleep as another “achievement,” rather than as something we let happen. We humans have the unique ability to push sleep away.  In the case of my patient described above, we’ve taken a pragmatic approach to her sleep problem–our biggest accomplishment so far has been working together to carve out a precious hour in her day….to take a nap.

Melissa Lim, MD

Sleep Specialist

Redwood City, CA

BRAIN TOILETING: Flushing Out the Purpose of Sleep

When new healthcare students look at me quizzically, as I recommend “pulmonary toilet measures” in the care of a patient, I am sure their look also connotes a tinge of, “What is this dinosaur of a doctor saying?” When we speak of old fashioned ‘pulmonary toileting’, we refer to the various ways in which a patient, often with the assistance of a respiratory therapist, cleans out their lungs, whether it be with increased physical activity, medications and bedside tools to break up mucus, or tipping a patient head down and beating them gently on the back. After some combination of these methods, the lungs are better cleared and cleaned of thick mucus and cellular debris. These methods have been known for decades as tools for assisting patients in the natural function of their lungs, especially when the lungs are compromised by respiratory infections.

In the area of sleep medicine, we have yet to answer the fundamental question as to the purpose of sleep. We know that animals universally undertake this activity, despite sleep’s inherent dangers in the dog-eat-dog animal kingdom. It’s no surprise that giraffes evolved to sleep 30 minutes a day (and do not lie down for more than 5 minutes!), whereas tigers sleep for 18 hours a day. Given its universality, then, sleep must be important. Some theories include the energy conservation theory, which is supported by a decreased caloric consumption that occurs during sleep. A second theory is that sleep serves a restorative function. For example, nocturnal growth hormone secretion may facilitate cell regeneration and muscle growth. More recently, researchers have described the metabolic clearance of toxic waste that occurs during sleep, or a form of “brain toileting,” to be concise. In animal models of sleep, there is a demonstrable increase in the volume of the fluid outside of and in between brain cells (Xie et al, Science, 2013 October; 342 (6156): 373-7), and in the clearance of beta-amyloid, one of the proteins found in abundance in brains of patients with Alzheimer’s disease. Dr. Maiken Nedergaard of the University of Rochester refers to a “glymphatic system,” much like the body’s lymphatic system, whereby the brain’s glial cells drive the exit of brain’s cellular byproducts into the cerebrospinal fluid for removal, and discovered that this system is the most active during sleep (see “Goodnight. Sleep Clean.” by M. Konnikova, NY Times, Jan. 10, 2014). Conversely, in sleep deprived animals, the clearance of brain toxins is significantly reduced. Although the corollary research in humans remains pending, the implications are many. As a whole, we sleep fewer hours per night than we did generations before, and sleep deprivation is steadily increasing. For instance in 2013, 40% of Gallup respondents said they slept 6 hours or less per night, whereas only 11% responded the same in 1942 ( Insomnia and insufficient sleep, from myriad causes, are prevalent in modern society, potentially increasing our risk of, or accelerating, neurocognitive decline.

Whether knowledge of the health risks of sleep deprivation and the health benefits of a good night’s sleep on a regular basis is enough to spur us to change our or our patients’ behavior is questionable. The inevitable alternative is that we will develop medications that enhance the glymphatic system despite sleep loss, or optimize its function during its quiescent state, i.e. while we are awake. At the very least, honing in on the purpose of sleep will help us educate our patients and provide additional ammunition to encourage lifestyle changes that enhance the opportunity to sleep. Until we learn to turn our lights off and take our brains to the loo, that may be the best we can do.

Melissa S. Lim, MD

Sleep specialist, Redwood City, CA