Cancer and Sleep
People living with cancer are dealing with a range of conditions that make life more challenging: frequent doctor’s appointments, painful symptoms, uncomfortable side effects, and more. Trouble sleeping is yet another complication and its effects are pervasive.
Without sufficient sleep, pain feels more acute and emotions are more difficult to manage. Being exhausted makes it tough to keep a positive mindset and cope with the challenges of cancer.
Not only do sleep problems impact the experience of living with cancer, but an increasing amount of evidence suggests that sleep problems before cancer may actually increase one’s cancer risk as well.
Understanding how sleep is tied to cancer is important for reducing your cancer risk, and for learning how to make sleep problems during treatment more tolerable. Below we’ll review the link between cancer and sleep, common sleep problems associated with cancer, and actionable advice for sleeping better while living with cancer.
Can You Get Cancer From a Lack of Sleep?
While scientists agree that good sleep is essential to overall health, they have not yet determined lack of sleep to officially cause cancer. However, a significant amount of research does suggest a link between lack of sleep and an increased risk for various cancers.
The lack of sleep associated with cancer is most often related to chronic sleep deprivation, sleep apnea, and shift work sleep disorder.
Generally, sleep deprivation refers to any time a person has not had sufficient sleep (defined as at least 7 hours nightly for adults, although the specific amount you need may be more or less than that).
A person feels sleep-deprived after an all-nighter, but the kind of sleep deprivation associated with cancer is chronic. It can develop from insomnia, where a person regularly has difficulty falling asleep and getting the amount of sleep they need. It can even occur when they do get a full night of sleep, but that sleep isn’t truly restful. This second scenario is common with sleep apnea or shift work sleep disorder, both of which we’ll review in the following sections.
Chronic sleep deprivation impairs your cognition, worsens your judgment, and lessens your ability to regulate your mood, resulting in irritability and moodiness. It also weakens your immune system and may lead to weight gain, both of which help explain why sleep deprivation is linked with obesity, diabetes, and other serious health conditions.
Many of the symptoms of sleep deprivation lead to health outcomes that are themselves risk factors for cancer (obesity, etc.). However, a growing body of research suggests that lack of sleep itself may be an independent risk factor for several cancers:
- Prostate cancer: A 2013 study followed over 2,100 men between a period of three to seven years. The men with insomnia were between 1.7 to 2.1 times more likely to develop prostate cancer within that time frame. The worse their sleep deprivation, the more severe their prostate cancer.
- Breast cancer: A 2008 study of nearly 24,000 women found that those who slept 6 hours per day were 1.62 times more likely to develop breast cancer than those who received a healthy 7 hours. Like the prostate study cited above, another 2012 study found that lack of sleep also tended to correlate with more severe forms of breast cancer.
- Colon cancer: When it comes to sleep, every hour counts. One study found that individuals who slept fewer than 6 hours per night were 50% more likely to develop colon cancer than individuals who sleep at least 7 hours. These individuals were also more likely to report a sleep apnea diagnosis or work shift work.
Sleep apnea is a potentially life-threatening sleep disorder where the person stops breathing during sleep. This results in choking, gasping, or disruptive snoring, forcing the brain to temporarily wake up to begin breathing again. Often, the person will be roused by their apnea, but even if instances where they don’t consciously wake up, the disruption still interferes with the overall quality of their sleep.
Ideally, high-quality sleep describes a full 7 hours of uninterrupted sleep. Several times during this period, the sleeper cycles through the various stages of sleep, from light sleep to deep sleep to REM sleep. Each of these stages serves a different purpose. Deep sleep repairs the body muscles and tissue, while REM sleep repairs the mind - processing memories, emotions, and dreams.
We experience the bulk of our REM sleep in the latter half of the night. If sleep is interrupted due to sleep apnea, the cycles effectively start over again, resulting in reduced REM sleep. Less REM sleep causes the emotional and cognitive deficits of sleep deprivation. While a positive attitude may or may not be linked with increased cancer survival, it certainly makes managing the symptoms of cancer more tolerable.
Sleep apnea can develop when the airways are obstructed, such as with obesity (the fatty tissues around the throat block the airways), or from a communication issue between the brain and the breathing muscles.
Sleep apnea is associated with diabetes, obesity, and cardiovascular disease. Recent research indicates may also be linked with cancer:
- Head and neck cancer: In one study, 80% of the individuals with head and neck cancer also had sleep apnea, and they were more likely to suffer postoperative complications.
- Severity of cancer: A large study of nearly 5,000 individuals found a correlation between the severity of sleep apnea and cancer onset. Males younger than 65 years old were at particular risk.
- Cancer morbidity: One study categorized patients based on the severity of their sleep apnea. The ones with the most extreme sleep apnea were 5 times likelier to die from cancer.
A 2014 study of mice illuminates a potential why behind the link between cancer and sleep apnea. Mice infected with tumors were separated into two groups. Researchers then placed one group in a low-oxygen environment to recreate the condition of having sleep apnea (sleep apnea reduces the oxygen levels in your blood). The mice in the reduced oxygen environment (the “SF” lines in the charts below) experienced accelerated tumor growth compared to the control (“SC”):
The body reacts to reduced oxygen levels by increasing blood vessel production. That increased blood vessel production in turn gives cancerous tissue a growth boost.
Shift work sleep disorder
Shift work sleep disorder is a circadian rhythm disorder that affects individuals who work alternative work schedules, such as overnight or rotating shifts.
Your circadian rhythm describes your body’s natural patterns, such as when you feel hungry, when you feel tired, when you feel energized, etc. The circadian rhythms of humans line up nicely with the patterns of the sun - circadian literally means ”around the day.”
The lives of shift workers often operate in direct opposition to their circadian rhythms, causing them to live in a perpetual sense of jet lag and sleep deprivation. As a result, they’re much more likely to suffer from all the symptoms of sleep deprivation, including worsened mood, judgment, and cognitive performance.
Shift work sleep disorder is associated with an increased risk of several cancers:
- Prostate cancer: Several studies have observed an increased risk of prostate cancer with shift work.
- Breast cancer: Women who perform shift work demonstrated increased breast cancer risk.
- Colorectal cancer: A 2003 study of night-shift nurses found that those who worked rotating night shifts for 15 years or more, even just for 3 nights a month, experienced a significantly increased risk of colorectal cancer. Studies like this suggest that cancer risk may increase according to the length of time spent having a career in shift work.
The disruption to these shift workers’ circadian rhythms doesn’t merely affect their sleep. As we mentioned above, your circadian rhythms play a role in the daily schedule of a host of your biological functions, including hormone production and organ function. Adhering to an abnormal circadian cycle could make those other functions more vulnerable to healthy operation, too.
Hormone production in particular might explain the relationship between sleep problems and cancer incidence in shift workers. Melatonin is the hormone that regulates your sleep. Your brain relies on sunlight to know when nighttime is approaching, at which point it begins melatonin production. Because shift workers miss a lot of sunlight, and also experience a high amount of artificial light during times that are characteristically dark, they experience significantly lower melatonin production.
Like most biological functions, melatonin doesn’t operate in a vacuum. With lower melatonin levels comes increased estrogen production - which is tied with breast cancer risk. A 2003 study linked lower melatonin levels with increased breast cancer risk, and researchers hypothesized it was due to the patients’ estrogen levels.
Stress hormone cortisol also operates in inverse to melatonin, rising in the morning and lowering at night. Studies have found that individuals who perform shift work typically have higher overall cortisol levels. Stress is a leading contributor to insomnia, as it interferes with your ability to relax and calm your mind sufficiently to fall asleep.
Sleep Problems Associated With Cancer
Unfortunately, the sleep problems don’t stop with a cancer diagnosis. Typically, they get worse.
The symptoms of cancer and cancer treatment are wide-ranging and disruptive to all aspects of daily life, including sleep. Cancer treatment may cause new sleep problems of its own or exacerbate existing ones. Individuals experience higher levels of pain and discomfort, so it’s tougher to feel comfortable enough to sleep. They may also experience night sweats that disrupt their sleep. Finally, a cancer diagnosis can understandably lead to depression and anxiety, both of which are strongly correlated with insomnia.
Up to 70% of women with breast cancer and 50% of men with prostate cancer experience sleep problems. Generally, regardless of the type of cancer, somewhere between 30 to 75% of cancer patients experience issues with sleep.
Cancer treatment most commonly causes fatigue, excessive daytime sleepiness, insomnia, and restless legs syndrome.
Fatigue and excessive daytime sleepiness
Fatigue describes extreme tiredness or exhaustion. Cancer treatment and chemotherapy drugs often cause fatigue.
Excessive daytime sleepiness describes a feeling of extreme sluggishness that persists throughout the day. Individuals feel unrested, even after a night of apparently adequate sleep. Many anti-nausea medications prescribed to cancer patients include this kind of drowsiness as a side effect.
Although similar, excessive daytime sleepiness is distinct from fatigue, which describes low energy and a need to relax, while excessive daytime sleepiness is tied to a desire for sleep.
Cancer patients experiencing fatigue or excessive daytime sleepiness may be prone to nap during the day, which makes it harder to fall asleep at night.
Insomnia describes difficulty staying or falling asleep, such as waking too early or frequently during the night. Insomnia affects cancer patients at three times the rate of the general population.
It’s common for individuals with cancer to develop anxiety. Anxiety leads to stress, an activating sensation that makes it difficult to fall asleep at night. Plus, many cancer medications can also cause insomnia as a side effect. Steroids, for example, are extremely energizing.
Because of their insomnia, cancer patients may not get sufficient sleep at night, creating a cycle that results in more fatigue and exhaustion during the day.
Restless legs syndrome
Restless legs syndrome (RLS) strikes when the individual is lying down. They experience an extremely uncomfortable tingling sensation in their lower limbs, which can only be relieved by movement. This constant need to move the legs for relief makes it difficult to fall or stay asleep.
RLS appears to coexist with certain cancers. Women with breast cancer and older men with prostate cancer have a twofold risk for RLS. One study found 20% of individuals in chemotherapy had RLS. Again, that’s about twice the general population’s risk.
Tips for Better Sleep for Cancer Patients
Better sleep simply makes life easier. For those living with cancer, taking steps to improve sleep helps your body fight the cancer and helps your mind stay strong.
Therapeutic approaches to better sleep
Cognitive behavioral therapy for insomnia (CBT-I) is an effective treatment for many of the sleep problems experienced by cancer patients. Over the course of several sessions, patients work with their therapist on a variety of sleep techniques and best practices, including:
- Mental reframing: Patients review the negative thoughts and emotions they have around sleep, and begin to develop more positive and mindful habits.
- Relaxation techniques: Both progressive muscle relaxation and deep breathing exercises physically calm the body into a state conducive to sleep. The process of completing the exercises also gives the mind something to focus on, other than the worries and anxiety about their cancer.
- Sleep hygiene: Patients learn about good sleep behavior, such as following a bedtime routine, adhering to a consistent sleep schedule, keeping the bedroom cool and dark, and avoiding heavy meals, stimulating caffeine, or alcohol at night.
Sleep restriction therapy is sometimes practiced as part of CBT-I. During this practice, individuals work with their therapist to determine an appropriate daily sleep schedule, including their bed- and wake-times. Then, individuals adhere strictly to that schedule. They only spend time in bed when they are supposed to be asleep, and they get out of it at their wake time, whether or not they received their full 7 hours. They’re also not advised to take naps during the day. The idea behind sleep restriction is that it eventually forces the brain to naturally adhere to that set sleep schedule.
Light therapy uses specialized light boxes or lamps that provide the same brightness as the sun. Individuals sit in front of the light device for a specified amount of time, such as 15 minutes or 1 hour, to help reset their circadian clock. Light therapy is a recommended treatment for individuals with circadian rhythm disorders like shift workers.
CPAP therapy is the most effective treatment for individuals with extreme sleep apnea. The person sleeps with a CPAP mask over their face while they sleep. This mask is connected to a device that provides consistent air pressure, keeping their airways open while they sleep and preventing episodes of apnea.
Sleep products for cancer patients
Cooling mattresses can provide relief for cancer patients dealing with night sweats or hot flashes. These mattresses are designed with more breathable materials, such as gel-infused foams or latex, to provide a cooler sleep surface.
White noise machines help many individuals with insomnia fall asleep. These standalone electronics or smartphone apps have large libraries of nature sounds, classical music, or traditional white noise to block out distracting noise and thoughts.
Weighted blankets can be calming for a variety of individuals, but many patients with RLS find that they adequately soothe symptoms. The general guidance is to choose a blanket weighing 10 percent of your body weight, plus 1 pound.
- The American Cancer Society is the leading non-profit organization dedicated to fighting cancer, raising awareness, and funding research. The website offers a wealth of resources for cancer patients, cancer survivors, and their caregivers.
- The National Cancer Institute provides educational resources as well, while also publishing the results of the latest government-funded research.
- Cancer patients, survivors, and caregivers can find peer support through online forums such as the Cancer subreddit, The Cancer Forums, and the Cancer Survivors Network. The American Cancer Society also offers a 24-hour Live Chat and toll-free helpline available at 1-800-227-2345.