Here’s How Naps Affect Your Cancer Risk, According to a Sleep Specialist

We delve into how naps (and sleep overall) may affect your cancer risk so you know if it's a good idea to take a snooze—or if you should try to power through the rest of your day.

If a nap in the middle of your day sounds blissful, you’re probably not alone. Experts seem to go back and forth as to whether naps are good for us. They can give you a midday energy boost, but napping too long can be linked to some serious health ailments, including diabetes—and potentially cancer.

Eric Zhou, PhD, an assistant professor of sleep medicine at Harvard Medical School, tells The Healthy @Reader’s Digest that researchers aren’t entirely sure if naps raise or lower our risk for cancer.

“Maybe, but it’s probably not the napping. Rather, it is what the napping represents,” Zhou explains. For good sleepers, a nap is refreshing. For poor sleepers, however, the daytime nap reflects a necessity due to their insufficient and/or fragmented sleep patterns, he says.

“Daytime naps are common for patients with insomnia,” Zhou explains. A person with insomnia may have a bad night of sleep and have to be up early for work, so they can’t get enough sleep. They may struggle during the day and take a nap when they get home, which may feel great in the moment.

“But what they have done is they have had dessert before dinner, spoiling their appetite for sleep that night,” Zhou explains, which he says may cause larger issues for your health…including your risk of cancer.

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How can sleep affect cancer risk

“We do know from good data that insufficient sleep can increase the risk of developing cancer, and insomnia symptoms can increase mortality risk for those with cancer,” Dr. Zhou says.

He adds that 2021 research published in SLEEP indicates a link between poor sleep habits and lung cancer, while 2015 research published in Sleep Medicine found a connection to breast cancer.

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Why is that? Dr. Zhou explains that sleep problems may lead to immune dysregulation, inflammation and circadian rhythm disruptions. 2015 research published in Nature Communications also shows tumor cells may be most active at night, suggesting that there is a critical circadian element to cancer pathogenesis.

So if your sleep struggles may be raising your cancer risk—can napping be the solution?

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The verdict on how naps affect cancer risk

If you’re a healthy person with regular sleep and wake cycles, a short nap in the day can help support healthy sleep and potentially reduce your cancer risk. In fact, Dr. Zhou calls it a “powerful reboot for your day.”

“It can improve cognition and feelings of sleepiness and fatigue,” Dr. Zhou says. “In specific contexts, like when someone is in a challenging work situation or is pregnant, daytime naps can be extremely valuable.”

That said, if you constantly feel like you want to nap during the day, something more serious may be afoot—so it’s important to see a doctor.

For more wellness updates, subscribe to The Healthy @Reader’s Digest newsletter and follow The Healthy on Facebook and Instagram. Keep reading:

Cancer: "Short duration of sleep increases risk of colorectal adenoma." SLEEP: "Actigraphy-Measured Sleep Disruption as a Predictor of Survival among Women with Advanced Breast Cancer." Sleep Medicine: "Night-shift work, sleep duration, daytime napping, and breast cancer risk." SLEEP: "Relationships between sleep traits and lung cancer risk: a prospective cohort study in UK Biobank." Epidemiology: "Sleep quality, duration, and breast cancer aggressiveness." BMC Cancer: "Sleep duration and the risk of cancer: a systematic review and meta-analysis including dose–response relationship." Nature: "Diurnal suppression of EGFR signalling by glucocorticoids and implications for tumour progression and treatment." Sleep and Biological Rhythms: "A dose-response investigation of the benefits of napping in healthy young, middle-aged and older adults." Journal of Clinical Sleep Medicine: "Minimal Effect of Daytime Napping Behavior on Nocturnal Sleep in Pregnant Women."

Kristen Fischer
After earning a science degree from Stockton University, Kristen Fischer ( decided to pursue writing instead. Since then, she has written about women's health, psychology, parenting, mental health--and everything in between. Her work has been published at Prevention, WebMD, Healthline, Motherly, and Parade. Kristen loves translating scientific jargon so people are empowered about their health. She lives at the Jersey Shore with her husband, son, and four cats.