There are few ingredients more important to wellness than sleep. A good night’s sleep can enable us to awaken refreshed, ready to face the day’s challenges. Conversely, lack of sleep can result in a variety of physical, emotional, and mental problems. This will be the first of two blogs covering sleep, including general information on sleep, sleep disorders, and treatments and recommendations for troubled sleep.
Why is sleep so important?
There are many benefits to sleep, both physical and mental. Sleep is important in the regulation of blood pressure, the endocrine system, and appetite, and helps to boost the immune system.Sleep also aids cognitive functioning, and improves the ability to learn, remember, and problem solve, and enables individuals to cope better emotionally.
What is a normal sleep pattern?
The sleep-wake cycle is controlled by circadian rhythm, an inborn biological clock. As the night progresses, we pass through several sleep stages in a set pattern, with each cycle lasting about 90 minutes. There are two main sleep phases: REM (rapid eye movement) sleep accounts for about 25% of our sleep time, and consists of periods of rapid eye movement in which the brain is active but the body is at rest. This is the phase in which we dream. NREM (non-REM) sleep takes up the other 75% of our sleep and is made up of 4 quiet, restful stages of increasingly deep sleep.
As I’ve aged, my sleep has changed. Is this normal?
Yes, sleep patterns often change as people get older. Older people sleep less deeply: they awaken more frequently, get up earlier in the morning, get less REM (deep) sleep, spend more time in lighter phases of sleep, and spend more time in bed NOT sleeping. But the need for sleep is the same among older and younger people, so it is common for older folks to have more naps or to be sleepier during the day. Older folks may also be more likely to have advanced sleep phase syndrome, in which they go to sleep earlier and awaken earlier.
What are some common sleep disorders?
Insomnia, or the inability to get a full night’s sleep, is diagnosed in about 10-15% of the general population1. An official diagnosis of insomnia requires difficulty initiating, maintaining sleep, or an inability to return to sleep after an early-morning awakening, at least 3 nights per week for at least 3 months, with significant daytime impairment, and the problem is not explained by another physical or mental condition2. There can be a multitude of causes for insomnia, including anxiety, depression, distress, medications, circadian rhythm disorder, or poor sleep habits. Snoring can be a minor irritation, or a symptom of a serious problem, obstructive sleep apnea, in which the airway is partially or completely blocked and breathing is interrupted. Sleep apnea is dangerous and may lead to severe daytime sleepiness, high blood pressure, stroke, or heart attack. Circadian rhythm disorders result from abnormalities in the “clock” in the brain that regulates sleep. The irregularities may be due to jet lag, shift work, or delayed or advanced sleep phase syndrome.
What types of sleep problems are common among cancer patients?
Not surprisingly, about 30-50% of cancer patients report problems with sleep, with the most common disorders being insomnia and an abnormal sleep-wake cycle3. About 28% meet the official criteria for insomnia, which may begin before, after, or during treatment, and may persist for years after treatment has ended3. Cancer patients may have difficulty sleeping due to many problems, including the effects of the tumor (pressure or pain from the tumor, fever, trouble breathing), side effects from treatments or medications (pain, anxiety, night sweats, gastrointestinal or bladder problems)5, difficulty sleeping while inpatient (factors related to the hospital environment, such as being in an unfamiliar bed, having unwanted noise, being in a room that is too hot or too cold), or factors related to the hospital routine (interruptions from doctor or nurse visits, going for scans or procedures, getting medications or treatment)5.
What are the consequences of sleep disorders in cancer patients?
Poor quality sleep in cancer patients impairs several domains, and is correlated with increased pain, depression, and fatigue, and decreased functioning, quality of life, and treatment adherence. Importantly, sleep disturbances are associated with increased cancer-related morbidity and poor outcomes3.
How are sleep problems assessed?
Most cancer patients with sleep difficulties are assessed with a physical exam and health history, including documentation of side effects of cancer and cancer treatment, medications, diet, and exercise. A detailed sleep history is also taken, including description of sleep patterns and duration of the problem. If warranted, the “gold standard’ of a sleep assessment includes a polysomnogram, or sleep study, an overnight test in which the patient sleeps while hooked up to sensors recording brain waves, eye movements, breathing rate, blood pressure, heart rate and electrical activity of the heart. The results of this test can identify irregularities relating to sleep patterns, breathing, limb movement, or other unusual behaviors.
When should I make a referral to a sleep specialist? Appropriate referrals occur when the patient has excessive daytime sleepiness, is acting out during sleep, or is thought to have sleep apnea or restless legs syndrome.
- National Sleep Foundation; Insomnia & Sleep. Arlington, VA: National Sleep Foundation, 2013.
- American Psychiatric Association: Desk Reference to the Diagnostic Criteria from DSM-5. Arlington, VA, American Psychiatric Association, 2013.
- Savard J, Ivers H, Villa J, et al: Natural course of insomnia comorbid with cancer: an 18-month longitudinal study. J Clinical Onc. 2011;29:3580-3586.
- Vena C, Parker K, CunninghamM et al: Sleep-wake disturbances in people with cancer part 1: an overview of sleep, sleep regulation, and effects of disease and treatment. Oncol Nurs Forum. 2004;31(4):735-746.
- Boonstra L, Harden K, Jarvis S, et al: Sleep disturbance in hospitalized recipients of stem cell transplantation. Clin J Oncol Nurs. 2011;15(3):271-276.