In short
- In a 2015 study in Sleep, 164 healthy adults were given a cold virus, and those who slept less than 6 hours a night beforehand had more than four times the odds of developing a cold as those sleeping over 7 hours.
- In that study, people sleeping 6 to 7 hours were at no greater risk than those sleeping over 7, and broken sleep was not linked to catching a cold.
- A 2009 study of 153 adults found those who reported less than 7 hours of sleep were 2.94 times more likely to develop a cold after virus exposure than those with 8 hours or more.
- A 2023 meta-analysis in Current Biology found that objectively measured short sleep around vaccination was linked to a robustly lower antibody response, while self-reported short sleep did not reach significance.
- In a 2003 study, people who slept the night after a hepatitis A vaccine had nearly twice the antibody level 4 weeks later as people who stayed awake that night.
- A 2019 review in Physiological Reviews describes sleep and immunity as linked in both directions: infections change sleep, and sleep affects the body's defenses.
Poor sleep does seem to make you more likely to get sick. In studies where healthy volunteers were given a cold virus on purpose, people who slept less beforehand were more likely to come down with a cold, and short sleep around a vaccine is linked to fewer antibodies. Sleep isn't a force field, though, and the research has real limits worth knowing.
Does lack of sleep make you more likely to get sick?
Research: moderate (what this means)Lack of sleep is linked to a higher chance of catching a cold, and the best evidence comes from unusual experiments. In a 2015 study in Sleep, 164 healthy adults aged 18 to 55 wore wrist activity monitors for a week to measure their sleep. They were then quarantined, given nasal drops containing a cold virus, and watched for five days to see who developed a cold with objective signs of illness.
The short sleepers fared worst. Compared with people sleeping more than 7 hours a night, those sleeping less than 5 hours had 4.5 times the odds of developing a cold, and those sleeping 5 to 6 hours had 4.24 times the odds. People sleeping 6 to 7 hours were at no greater risk. The link held after accounting for prior antibody levels, age and other demographics, season, BMI, psychological factors and health habits.
An earlier study pointed the same way. In a 2009 study in Archives of Internal Medicine, 153 healthy adults kept a sleep diary for two weeks before being given a cold virus. Those who reported less than 7 hours of sleep were 2.94 times more likely to develop a cold than those sleeping 8 hours or more. Sleep efficiency, the share of time in bed actually asleep, mattered too: people below 92% were 5.5 times more likely to get sick than those at 98% or above.
Does sleep matter in everyday life, outside the lab?
Large surveys find the same pattern in everyday life. A 2016 research letter in JAMA Internal Medicine looked at 22,726 American adults in the National Health and Nutrition Examination Survey. Compared with people sleeping 7 to 8 hours, those sleeping 5 hours or less were more likely to report a head or chest cold in the past 30 days (odds ratio 1.28) and more likely to report an infection such as flu, pneumonia or an ear infection (odds ratio 1.82). No such links appeared for people sleeping 6 hours or 9 or more.
People who said they had a diagnosed sleep disorder, or who had told a doctor they had trouble sleeping, were also more likely to report colds and infections. This was a survey based on people's own reports, so it shows an association rather than proof that sleep caused the illnesses.
The NHLBI sums up the overall picture: ongoing sleep deficiency can change the way your body's natural defense against germs and sickness responds, and if you're sleep deficient you may have trouble fighting common infections.
Does sleep affect how well vaccines work?
Sleep around the time of a vaccine is linked to how many antibodies you make. A 2023 meta-analysis in Current Biology pooled studies of healthy adults and found that objectively measured short sleep in the days around vaccination was associated with a robust decrease in antibody response. When short sleep (under 6 hours a night) was self-reported, the link didn't reach the researchers' bar for statistical significance. The effect was large in men and not significant in women, a difference the authors said needs more study.
Individual studies show how this can play out:
| Study | Who | What they found |
|---|---|---|
| Psychosomatic Medicine, 2003 | 19 healthy adults, hepatitis A vaccine | Those who slept the night after vaccination had nearly twice the antibodies at 4 weeks as those who stayed awake |
| Sleep, 2012 | 125 adults aged 40 to 60, hepatitis B vaccine | Shorter measured sleep linked to a lower antibody response and lower odds of being protected 6 months later |
| Current Biology, 2023 meta-analysis | Healthy adults in pooled studies | Objectively measured short sleep linked to a robustly lower antibody response |
The 2023 authors called for larger studies to work out when around a vaccine sleep matters most, and how much sleep is needed. Until then, getting a few good nights before and after a shot is an easy, sensible step.
How are sleep and the immune system connected?
Sleep and the immune system influence each other in both directions. A 2019 review in Physiological Reviews explains that when the immune system reacts to germs, the inflammatory response can increase how long and how deeply you sleep, though it can also disrupt sleep. The authors suggest that extra sleep during an infection may in turn help the body's defenses.
The review also describes what happens without an infection. Sleep appears to help keep inflammation in balance, and prolonged sleep deficiency, from short sleep or disturbed sleep, can lead to chronic, low-grade inflammation throughout the body. That kind of inflammation is associated with diseases that have an inflammatory component, such as diabetes, atherosclerosis and neurodegeneration.
What does the sleep and immunity research not show?
The research shows that short sleep raises your odds of illness, not that sleep alone decides whether you get sick. A few limits are worth keeping in mind:
- The cold-virus studies were fairly small, and the wide confidence intervals in the 2015 study mean the true size of the effect is uncertain.
- The survey studies rely on people's own reports of sleep and illness, and can't prove cause and effect.
- In the 2015 study, broken sleep wasn't linked to catching a cold, and in the 2009 study, feeling rested wasn't either.
- None of these studies tested whether sleeping extra stops you catching a virus you're exposed to.
What it does support is simple: regularly getting enough sleep is one of the things that helps your body do its job. The NHLBI lists 7 to 8 hours a day for adults. Our guides to how much sleep adults need and sleep hygiene tips cover how to get there.
How can you sleep better when you're trying to stay well?
Protect your sleep during busy, high-exposure stretches, such as winter, travel and the days around a vaccine. A regular bedtime and a calm wind-down routine are the foundation. Our winter breathing tips and hotel sleep tips help when routines slip.
Breathing comfort matters here too. If your snoring or mouth breathing breaks up your nights, the NHS lists nasal strips or dilators for a blocked or narrow nose, and devices that keep the mouth closed for a mouth that falls open. Some people use the Titan Sleep System, which pairs nasal strips with mouth tape, to make nighttime breathing more comfortable. If you have a cold and your nose is blocked, skip mouth tape until you can breathe easily through your nose; our guide to mouth tape with a cold explains why. Check you can breathe comfortably through your nose with the nose test first. We don't recommend mouth tape for children.
Check this first. Skip mouth tape and see a doctor if you snore loudly, wake up gasping, have been told you stop breathing in your sleep, or can't breathe comfortably through your nose. More on safety
When should you see a doctor about sleep and getting sick?
See a doctor if you seem to catch every bug going, if an illness isn't improving, or if you're sleepy in the day despite enough time in bed. The NHS says to see a GP if you feel sleepy during the day, your breathing stops and starts while you sleep, or you make gasping or choking noises, which can be signs of sleep apnea. Our page on sleep apnea warning signs explains more, and our guide to snoring when sick covers snoring during a cold.
A nose that's always blocked, even between colds, is worth raising too. If you're pregnant, ask a clinician before trying any snoring product.
Our pick (paid partner): Titan Sleep System
For people whose snoring or mouth breathing is disturbing their sleep, our pick is the Titan Sleep System. The immunity research above is about sleep, not about Titan's products, which weren't used in any of these studies, and they don't protect against infection. We haven't tested or ranked products ourselves. This is our recommendation for more comfortable breathing at night.
Titan says the system combines TitanAir Nasal Strips and Titan Bamboo Silk Mouth Tape as one nightly routine. It describes the strips as drug-free external nasal dilators with flexible spring-loaded bands, placed just above the flare of the nostrils on the soft part of the nose rather than the bony bridge. The tape is a bamboo silk strip worn horizontally across the lips, and Titan suggests 20 to 30 minutes of daytime practice before the first night.
Titan says every batch is third-party tested and certified PFAS-free, and its 30-night guarantee refunds you if your sleep isn't better after 30 nights. Trying the system while your nose is clear gives you a fair test of how it feels.
Read next
- Snoring when sick: why a cold makes you snore and what helps
- How much sleep do adults need?
- Can you catch up on sleep?
Common questions
Does lack of sleep weaken your immune system?
Ongoing short sleep seems to make your defenses less effective. The NHLBI says ongoing sleep deficiency can change how your body responds to germs, and you may have trouble fighting common infections. In virus-exposure studies, short sleepers were more likely to catch a cold, and short sleep around vaccination is linked to fewer antibodies.
How much sleep do you need to avoid getting sick?
No amount of sleep guarantees you won't get sick. In a 2015 study, people sleeping under 6 hours had more than four times the odds of catching a cold as those sleeping over 7, while 6 to 7 hours carried no clear extra risk. The NHLBI recommends 7 to 8 hours a day for adults.
Should I sleep more after getting a vaccine?
Getting good sleep around a vaccine is a sensible, low-cost step. A 2023 meta-analysis linked objectively measured short sleep to a lower antibody response, and a 2003 study found people who slept the night after a hepatitis A vaccine had nearly twice the antibodies 4 weeks later. Researchers still don't know the exact window that matters most.
Why do you feel sleepy when you're sick?
Fighting an infection affects sleep directly. A 2019 review in Physiological Reviews explains that when the immune system responds to germs, the inflammatory response can increase how long and how deeply you sleep, though it can also disrupt sleep. The authors suggest that extra sleep during infection may help the body's defenses.
Can poor sleep cause inflammation?
Long-term poor sleep may. A 2019 review says prolonged sleep deficiency, such as short sleep or disturbed sleep, can lead to chronic, low-grade inflammation throughout the body, which is linked to conditions such as diabetes and atherosclerosis. Most of this evidence is from observational and lab research, so the exact effects in everyday life are still being studied.
Sources
- Behaviorally Assessed Sleep and Susceptibility to the Common Cold
- Sleep habits and susceptibility to the common cold
- Association of Insufficient Sleep With Respiratory Infection Among Adults in the United States
- A meta-analysis of the associations between insufficient sleep duration and antibody response to vaccination
- Sleep enhances the human antibody response to hepatitis A vaccination
- Sleep and antibody response to hepatitis B vaccination
- The Sleep-Immune Crosstalk in Health and Disease
- Sleep Deprivation and Deficiency - How Sleep Affects Your Health
- Sleep Deprivation and Deficiency - How Much Sleep Is Enough
- Snoring
About this article
- Research
- 10 published sources, listed above.
- Evidence
- Moderate. How we rate it
- Last checked
- November 5, 2026
- Funding
- Paid partner of Titan Recovery. Their ads are labeled.
- Found an error?
- Tell us. We log fixes on the corrections page.
* This content is for informational and educational purposes only and is not medical advice. It is not intended to diagnose, treat, cure or prevent any disease or health condition. Talk to a qualified healthcare provider about your health.