Is Your Sleep Quality Making You Sick?

[Nelson Vergel]

From:


Opinion | Yes, Your Sleep Schedule Is Making You Sick
Most of us have an indirect sense of our internal clock time just by knowing when we prefer to go to bed. But you can get a more objective measure of your circadian rhythm — or chronotype — and advice on what to do about it by taking this simple quiz.

Those with more serious problems than jet lag and late nights may need to make more serious changes.


Researchers have developed a limited form of sleep deprivation that is euphemistically called wake therapy. It has been shown to have sustained antidepressant benefit in patients with bipolar disorder and major depression. The idea is to get up for the day halfway through the usual sleep period, which shifts the circadian clock to an earlier time. It’s thought that this works by realigning the sleep cycle with other circadian rhythms, like changes in levels of body temperature and the stress hormone cortisol, that are also out of sync with each other in depression.


Studies show that it is possible to make wake therapy even more powerful by incorporating two additional interventions: early morning light therapy and what’s called sleep phase advance, in which the patient goes to bed about five to six hours earlier than usual and sleeps for about seven hours. This combination of treatments is called triple chronotherapy, and the typical course involves one night of complete sleep deprivation followed by three nights of phase-advanced sleep and early morning light.


In one study of 60 hospitalized patients with bipolar depression who were taking antidepressants or lithium, 70 percent of those who did not have a history of drug resistance improved rapidly with sleep deprivation and early morning light, and 57 percent remained well after nine months. Encouragingly, 44 percent of patients who had failed to respond to at least one trial of anti-depressants also improved.


In another study, investigators combined chronotherapy with psychotropic medication and found that depressed patients got better within 48 hours — much faster than antidepressants, which typically take four to six weeks to work. A second study of 75 depressed patients who were taking an antidepressant randomly assigned half to also receive chronotherapy and the other half to daily physical exercise. It found that 62 percent of patients remained well at the end of 29 weeks in the chronotherapy group compared with only 38 percent assigned to exercise.



With the possible exception of ketamine, a drug under investigation for treating depression, this therapy is the most rapid antidepressant treatment that we have. About 60 percent of depressed patients feel markedly better within hours. And — with the exception of some fatigue — there are no side effects.

 

[Nelson Vergel]

Humans Out-of-Sync

Humans are not immune to the type of clock disruptions documented in mice.

Decades of epidemiologic studies show workers with overnight shifts or other schedules out of sync with the light-dark cycle have an increased risk of weight gain and diabetes. Genetic mutations in human clock genes have been associated with obesity and metabolic disease. Conversely, a variation in the gene encoding the melatonin receptor has been linked to a higher risk of developing type-2 diabetes.

Even those without genetic mutations or unusual schedules may be at risk of clock disturbances. Thanks to light pollution and growing nighttime use of light bulbs and electronic devices that emit the same wavelengths of light as the sun, many otherwise healthy individuals may experience sleep disturbances or circadian disruptions.

“We live in a society where sleep is not respected,” Van Cauter said.

But sleep, circadian rhythms, and metabolism make up an “inseparable triad,” she noted. Insufficient sleep has been shown to have a harmful impact on glucose tolerance in many populations including healthy adults, children, hospitalized patients, and those with diabetes, she noted. It's also been shown to reduce resting metabolic rate to a large enough degree that it could translate to a 12.5-pound weight gain in a single year. Sleep restriction also increases hunger, Van Cauter noted. But restoring normal sleep can help reverse these ill effects.

“The work so far suggests that being sleep deprived and losing weight are contradictory,” she said. “To optimize weight loss, you need to sleep.”


Resetting the Circadian Clock Might Boost Metabolic Health

 

[Nelson Vergel]

How Your Circadian Rythm Rules Your Life