The short term effects of poor sleep may be tiredness and a lack of concentration but there is far more serious long term damage on the immune system, say scientists.
Poor-quality sleep marked by frequent awakenings can speed cancer growth, increase tumour aggressiveness and dampen the immune system's ability to control or eradicate early cancers, according to a new study published online in the journal Cancer Research.
The study is the first to demonstrate, using an animal model, the direct effects of fragmented sleep on tumour growth and invasiveness, and it points to a biological mechanism that could serve as a potential target for therapy.
"It's not the tumour, it's the immune system," said study director David Gozal, MD, chairman of pediatrics at the University of Chicago Comer Children's Hospital. "Fragmented sleep changes how the immune system deals with cancer in ways that make the disease more aggressive."
"Fortunately, our study also points to a potential drug target," he said. "Toll-like receptor 4, a biological messenger, helps control activation of the innate immune system. It appears to be a lynchpin for the cancer-promoting effects of sleep loss. The effects of fragmented sleep that we focused on were not seen in mice that lacked this protein."
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"It's easy to say that getting a good night of sleep doesn't matter, or put it off for an extra hour of TV or to catch up on work. But sleep is like exercise or eating well: you need to prioritize it and build it into your day. Sleep is vital, and one of the most important things you can do for your physical and mental health." -- Dr. Scott Kutscher, Assistant Professor of Sleep and Neurology at Vanderbilt University Medical Center
"Follow a regular routine. Try to get to bed and wake up about the same time each night." -- Dr. Susan Redline, MPH, Peter C. Farrell Professor of Sleep Medicine at Harvard Medical School "Whether you have the best night of sleep or a night where you toss and turn, the key to long-term sleep success, in my opinion, is to have a consistent wake time every morning. If you can pair that wake time with light (either real or artificial -- I use a light box) and exercise, it's even better." -- Dr. Christopher Winter, Medical Director of the Martha Jefferson Hospital Sleep Medicine Center "Consistent schedule. Consistent schedule. Consistent schedule! Set your alarm clock to go to bed." -- Dr. Russell Sanna, Harvard Medical School's Division of Sleep Medicine
"Create a relaxing bedtime ritual, like taking a warm bath or reading a magazine. It's important to unwind before getting into bed." -- Dr. David Volpi, founder EOS Sleep Centers
"Dim the lights one hour before desired bedtime and also turn off the screens one hour before bed. Light, including that from computers, iPads, TVs and smart phones, is the most powerful trigger for our neurotransmitters to switch to the 'on' position. If people have a tendency toward insomnia, they can be up for hours waiting to switch to turn off." -- Dr. Lisa Shives, founder of The Linden Center for Sleep and Weight Management in Chicago
"If you have trouble 'turning your mind off' as soon as you get into bed, it could mean that you have not given yourself enough time to work through the issues of the day. You maybe did some chores around the house, put the kids to bed, watched some TV -- that was plenty of time to wind down, right? Well, a lot of those activities are more distracting than relaxing. Instead of working through those thoughts and worries, you kept your mind busy doing something else. So, now that you are in bed, with nothing else to focus on, those thoughts come up again. A better approach would be to take some time in the evening to work through the day, make lists to do tomorrow and clear your mental desktop of all the stuff that you still have to think about. Then, get into bed." -- Michael A. Grandner, Ph.D., instructor of psychiatry at the Behavioral Sleep Medicine program at the University of Pennsylvania
"Get some exercise any time of day. Even a 10- to 15-minute walk each day could help you sleep better." -- Dr. Russell Rosenberg, Chair, National Sleep Foundation
"Most people who have sleep problems spend too much time in bed trying to sleep. If you are spending eight hours in bed and only sleeping six restless hours, why not get six hours of deeper sleep rather than eight hours of fragmented sleep? It's counterintuitive, but I recommend most of my insomnia patients go to bed a little (or a lot) later." -- Dr. Kelly Glazer Baron, assistant professor of neurology and director of the Behavioral Sleep Medicine Program at Northwestern University "If you're in bed tossing and turning, unable to sleep, get out of bed. You just make things worse by lying there. Don't get back into bed until you think you can sleep." -- Philip Gehrman, Ph.D., CBSM, clinical director of the Behavioral Sleep Medicine Program at the University of Pennsylvania
"Napping can help stave off the exhaustion from not getting enough nighttime sleep. It can increase your cognition by promoting the same level of memory improvement as a full night of sleep. It helps you process your emotions so you not only think better but you feel better after a nap. I would recommend people nap for five to 30 minutes or 60 to 90 minutes as often as possible. That amount of time will refresh you without letting you wake up groggy." -- Dr. Sara Mednick, author of Take a Nap! Change Your Life
"Make sure to get 15 minutes of sunlight every morning." -- Dr. Michael J. Breus, Ph.D., Clinical Psychologist; Board Certified Sleep Specialist
"If I could offer one small piece of advice, it would be to 'listen' to your bedpartner. If your partner snores, has pauses in breathing or kicks their legs during sleep, then let her or him know about it! Those afflicted with a sleep disorder are usually unaware of it. By simply 'listening' to one another, everyone will hopefully sleep better." -- Michael Decker, Ph.D., associate professor at the Frances Payne Bolton School of Nursing at Case Western Reserve University and a spokesperson for the American Academy of Sleep Medicine
"Even if you think they are helping you fall asleep initially, alcohol and medicines that make you drowsy may affect your sleep throughout the night. To achieve a sound, restful sleep, ensure the last two hours before bed are void of these items or any strenuous activity so your body realizes it’s time for bed." -- Dr. Matthew Mingrone, lead physician for EOS Sleep Centers in California
"Consider moisture wicking pajamas! Makes a huge difference for anyone prone to night sweats." -- James Maas, Ph.D., former fellow, professor and chairman of psychology at Cornell University
"Make your bed with separate sheets and blankets. It’s a small change with a big payoff. This will reduce copartner disturbance from movement and disturbance because of temperature. Use only one fitted sheet to start. Then make the top-of-bed with twin size flat sheets and blankets to meet each person's needs. If you're worried about how that will look -- no problem -- you can cover this up with a single comforter when dressing the bed each morning." -- Dr. Robert Oexman, director of the Sleep to Live Institute
Gozal, an authority on the consequences of sleep apnea, was struck by two recent studies linking apnoea to increased cancer mortality. So he and colleagues from the University of Chicago and the University of Louisville devised a series of experiments to measure the effects of disrupted sleep on cancer.
They used mice, housed in small groups. During the day - when mice normally sleep - a quiet, motorised brush moved through half of the cages every two minutes, forcing those mice to wake up and then go back to sleep. The rest of the mice were not disturbed.
After seven days in this setting, both groups of mice were injected with cells from one of two tumour types (TC-1 or 3LLC). All mice developed palpable tumors within 9 to 12 days. Four weeks after inoculation the researchers evaluated the tumours.
They found that tumours from mice with fragmented sleep were twice as large, for both tumour types, as those from mice that had slept normally. A follow-up experiment found that when tumour cells were implanted in the thigh muscle, which should help contain growth, the tumors were much more aggressive and invaded surrounding tissues in mice with disrupted sleep.
"In that setting, tumours are usually encased by a capsule of surrounding tissue, like a scar," Gozal said. "They form little spheres, with nice demarcation between cancerous and normal tissue. But in the fragmented-sleep mice, the tumours were much more invasive. They pushed through the capsule. They went into the muscle, into the bone. It was a mess."
"This study offers biological plausibility to the epidemiological associations between perturbed sleep and cancer outcomes," Gozal said. "The take home message is to take care of your sleep quality and quantity like you take care of your bank account."
"Considering the high prevalence of both sleep disorders and cancer in middle age or older populations," the authors wrote, "there are far-reaching implications."
Their next step is to determine whether sleep affects metastasis or resistance to cancer chemotherapy.