Why Good Sleep Matters During Cancer

With smartphones by our beds and enough stressful news to give anyone insomnia, it’s no wonder Americans are sleeping less than ever. The CDC found over a third (37.5%) of adults in Miami-Dade County don’t get enough sleep. For cancer researchers at Sylvester Comprehensive Cancer Center, a lack of sleep raises concerns about cancer risk and treatment outcomes.

“Fatigue and sleep disturbances are among the most frequently reported disease and treatment-related side effects in cancer, which have been shown to significantly affect quality of life, while also posing an increased risk of cancer recurrence,” says Loren Yavelberg, Ph.D., CEP, a post-doctoral associate at Sylvester Comprehensive Cancer Center, part of University of Miami Miller School of Medicine. Dr. Yavelberg and colleagues study lifestyle medicine, modifiable risk factors, and how people can reduce their cancer risk, as well as how to improve cancer treatment outcomes.

On most days, a lack of sleep shows up as grogginess, irritability, or an extra cup of coffee.

But for those going through cancer — and the caregivers who support them — sleep deficit has a very different kind of burden.

Sleep affects how our bodies, and specifically cells, heal. It shapes our mood, immune system, metabolism, stress hormones and ability to cope. “Sleep is our nightly repair shop. It’s when the body resets, clears waste, regulates hormones and repairs cells. Missing that opportunity means things pile up,” says Dr. Yavelberg.

What this means practically is that when sleep starts to unravel, everything else feels harder.

The good news is that sleep is also one of the most modifiable parts of daily life. “Small changes have big effects. Improving what you do during the day, so-called sleep hygiene, can go a long way, even during cancer treatment,” says Dr. Yavelberg.

Dr. Yavelberg and Youngmee Kim, Ph.D., a professor of psychology at the University of Miami who studies the effects of sleep on cancer patients, offer small, realistic changes to improve sleep quality and health. While they research cancer patients and their caregivers, their advice is relevant for anyone interested in improving their health.

The link between sleep and cancer

Sleep affects every part of cancer. A chronic lack of sleep is a cancer risk factor, a side effect for many and can affect cancer outcomes. A JAMA study found that sleep disruption from long periods of night shift work was associated with worse overall health, including an increase in cancer occurrence. “Circadian disruption from night shift work and light exposure at night can contribute to cancer risk, particularly for breast and colorectal cancers, but general sleep deficiency measured by duration or quality shows no consistent association,” says Judite Blanc, Ph.D., assistant professor of psychiatry and behavioral sciences at the Miller School.

Getting the sleep your body needs helps you feel better and stay healthier. The American Cancer Society recommends adults sleep about seven to eight hours on average at night.

Quality sleep matters at least as much as quantity.

“If you sleep 12 hours but wake up frequently, that’s not very beneficial. Someone who sleeps five or six hours uninterrupted can feel more rested,” says Dr. Yavelberg.

Of course, a few bad nights of sleep don’t increase your cancer risk or harm your treatment. What matters is long-term patterns, and even then, sleep is just one factor among many. “Cancer treatment is a stressful time, so it’s normal to have nights where it’s hard to sleep because of worries about a scan result or because of a side effect. Some nights of not sleeping well are not going to affect your cancer treatment,” says Dr. Kim. 

Why cancer makes sleep so difficult

Cancer disrupts sleep in multiple ways, physically and emotionally.

Stress and emotional overload

A cancer diagnosis introduces a level of uncertainty that can follow patients and families into the night. “It’s not only the person with cancer who has sleep problems. Having cancer in the family is a major stress for family caregivers, too,” says Dr. Kim.

Racing thoughts at bedtime are common, but they activate the same fight-or-flight systems that make it harder to fall or stay asleep.

Treatment side effects

Cancer medications, radiation and surgery can all interfere with sleep. Common culprits include:

• Pain
• Hot flashes or night sweats
• Nausea
• Frequent nighttime urination
• Medication-related alertness
• Medication-induced drowsiness that leads to napping during the day
• Hormonal changes

These symptoms can cause delayed sleep onset or fragmented sleep, making it harder to reach the restorative deep stages.

Inside UHealth research: Two studies on cancer and sleep

UHealth researchers are leading two studies that explore how sleep, stress, and daily habits affect cancer patients and caregivers.

A current NIH-funded study at UHealth offers a four-week, evidence-based sleep program for adults with gastrointestinal cancer and their caregivers. Dr. Kim and her team are working with couples to improve sleep-disrupting habits and modify unhelpful thoughts through small, gradual, evidence-based changes for both patients and their bedpartner caregivers.

Dr. Yavelberg and team also study whether prolonged overnight time-restricted eating and structured exercise can improve circadian alignment, sleep, fatigue, and quality of life for women with advanced breast cancer starting CDK4/6 inhibitor therapy.

While results for both studies are still in progress, the body of research in other populations suggests that circadian-friendly daily behavioral routines, as well as helpful thoughts and feelings, can improve sleep.

What healthy sleep looks like during cancer

Adults generally benefit from 7–8 hours of sleep. People in active cancer treatment may need more. However, the number of hours is only part of the picture.

Healthy sleep during cancer means:

• Falling asleep within a reasonable timeframe
• Staying asleep for longer stretches
• Waking up feeling somewhat restored
• Keeping consistent wake times

Healthy sleep doesn’t require perfection. “You don’t want to stay up all night thinking about how bad your sleep is. Don’t lose sleep over poor sleep,” says Dr. Yavelberg.

Practical ways for patients and caregivers to sleep better

Cancer can simultaneously cause exhaustion and an inability to sleep. “Cancer-induced fatigue is not actual sleepiness. Instead of napping, sometimes a short walk can help people feel less fatigued without disrupting nighttime sleep,” says Dr. Kim.

Plus, under stress, many people rely on routines that feel comforting in the moment but disrupt sleep later, like scrolling in bed, drinking caffeine late in the day or heavy evening meals. “Those behaviors can scrub your circadian rhythm. Once the sun rises, our biological clock wakes up, and when the sun goes down, it’s time to calm down,” says Dr. Kim.

Dr. Kim recommends the following tips to strengthen your daily sleep habits:

• Limit caffeine, alcohol, or nicotine intake some hours before bedtime
• Get moving each day, even if it’s just a short walk
• Keep your bedroom dark, quiet and cool
• Reserve the bed for sleep and intimacy
• Avoid screens in bed or within 30–60 minutes before bedtime
• Don’t go to bed unless you’re sleepy
• Wake up at a consistent time, even on weekends

When to ask for help

Talk to your cancer care team if:

• Sleep problems last more than a few weeks
• Fatigue is making treatment or daily life harder
• You rely on sleep medications most nights
• A partner notices loud snoring, gasping or pauses in breathing that might be sleep apnea

“Cancer patients should discuss sleep with their oncologist or mental health practitioner. For better outcomes, a personalized sleep health component that includes duration, quality and satisfaction should be part of the treatment or recovery plan,” says Dr. Blanc.

Sleep is a daily investment in strength, resilience and quality of life. For those going through cancer treatment and their caregivers, sleep is even more essential. One small change, like a cooler bedroom, a caffeine cutoff time, a short walk or a screen-free wind-down, can make a meaningful difference. “We tailor recommendations to each person so that we work together to find realistic changes,” says Dr. Kim.

Written by Wendy Margolin.

Tags: Circadian rhythm therapy, Dr. Loren Yavelberg, Dr. Youngmee Kim, Insomnia during chemotherapy, sleep and wakefulness, Sleep tracking for cancer recovery, Sylvester Comprehensive Cancer Center