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Why Does Cancer Cause Insomnia?

Cancer can rob you of the sleep you need to heal. Published research confirms that insomnia affects between half and three-quarters of all people who have been diagnosed with cancer. Other research suggests that 25 percent of cancer survivors continue to suffer from sleep problems.

This is problematic for one chief reason: sleep is your body’s best opportunity for healing.

The immune system needs the support of good sleep to prevent its suppression by hormone imbalances and therapeutic agents.

Without sleep, not only can cancer worsen, but other problems make living with cancer difficult, such as daytime fatigue, increased pain sensitivity, and mood disruption.

Let's take a closer look at insomnia and how it can affect people living with cancer.

What is insomnia?

Insomnia describes problems with sleeplessness. Either you have trouble falling asleep, trouble staying asleep, or you awaken far too early and can’t fall back asleep.

Acute insomnia describes sleeplessness that happens once in a while, but is completely disruptive to sleep-wake patterns and leads to noticeable problems with daytime sleepiness. Acute insomnia can occur following a new diagnosis or after a period of therapy.

Chronic insomnia describes regular patterns of sleeplessness that occur over a period of at least 4 weeks. Many people with cancer suffer from long-lasting periods of insomnia.

Why do people with blood cancer have insomnia?


If you had bouts of insomnia or a circadian rhythm disorder prior to your cancer diagnosis, these can become magnified when you are ill and even following successful treatment. Also, women and seniors tend to suffer more sleep problems, even when they don’t have cancer.

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Living with cancer naturally creates anxiety. Racing thoughts about your future, uncertainty about treatments, being overwhelmed by too much complex information and fearing potential relapses if you are a survivor all contribute to bedtime anxiety.


Treatments can contribute to sleep problems. Radiation and chemotherapy can create circadian disruptions, as can visits to the hospital (not a great place to sleep!) and the pain that cancer brings (pain is public enemy #1 of sleep).

Daytime naps

Sometimes you just need to sleep during the day. But that nap might delay your “sleep drive” at bedtime and make it harder for you to fall asleep.


Whether they are prescribed for cancer, pain, or other conditions (related or not), many common drugs can mess with your sleep architecture, leading to either daytime fatigue or insomnia.

Physical changes

Cancer and its disruptive growth and behavior can lead to things like anemia, hot flashes, and inflammation; these can cause daytime fatigue, which forces the need to nap, which lends to problems falling asleep or maintaining sleep. It's a vicious cycle.

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Tips to achieve better sleep

If you suffer from sleeplessness, it’s important to fight back. Poor sleep in people with cancer can lead to a lot of preventable problems, such as drowsy driving, decreases in cognitive function, lower quality of life, depression, poor treatment compliance, and even reduced survival rate.
You can take these steps to seek the relief you need so you can achieve better sleep at night and enjoy more alertness and less fatigue during the day.

  • Mention your sleep problems to your oncologist. They should have tools and strategies in place for helping you cope with insomnia. If your doctor doesn’t ask you about sleep, bring it up anyway. You may have mentioned these problems early into your diagnosis and treatment; if you are looking at post-treatment insomnia, you should still bring it up.
  • If you have daytime sleepiness, mention this to your doctor, too. Daytime fatigue has many causes, with cancer and cancer therapies only be two of them. You will want to identify the root causes of both your insomnia and daytime fatigue; if they are related to something other than cancer, you have more opportunities to address them separately so you can get the sleep you need to heal.
  • Be prepared to start a practice in CBT-i. If you’re lucky, your cancer treatment facility will offer cognitive behavioral therapy (CBT), or a specialized form for insomnia (CBT-i). These are nonpharmacological approaches which can help you reclaim the sleep you need at night and the energy you need during the day.
  • There are drug therapies that can be useful for getting sleep, but they come with risks. Also, melatonin itself can be a useful supplement with far fewer safety issues. Timing and dosage of these medications is critical; don’t go this route without the supervision of your oncologist or you might disrupt your circadian system and make things worse.
  • Some kind of regular exercise (ideally in the morning) can help you maintain strong circadian rhythms that promote sleep onset.
  • Practicing alternative techniques like yoga, stretches, yogic breathing and meditation can be very useful in providing the relaxation necessary to fall asleep.
  • Find ways to prioritize sleep. This means asking your support system to respect your need for sleep at any time of day. It also means investing in comfortable, dark, quiet sleeping spaces and practicing good sleep hygiene. For instance, don’t take any electronic devices to bed, as the blue spectrum light they emit will shut off your melatonin production. Also, avoid caffeinated products after lunch and skip the evening adult beverages; these contribute to poor sleep and nighttime awakenings.
This article represents the opinions, thoughts, and experiences of the author; none of this content has been paid for by any advertiser. The team does not recommend or endorse any products or treatments discussed herein. Learn more about how we maintain editorial integrity here.

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