Each year, 20% of the US population contract the common cold, and roughly 200,000 people are hospitalized with flu-related illnesses. Identifying ways to speed up recovery is essential. When we’re sick, most of us head straight to bed; but is this extra sleep vital, and will it help us recover faster?
In this guide, we’ll discuss whether sleep is an effective treatment for viral infections. Although sleep may help you recover from a cold, it’s not the only treatment out there. We’ll finish by discussing complementary ways you can support your immune system and fight a cold more.
Can You Sleep Off a Cold?
‘Get plenty of sleep!’ Most doctors prescribe sleep as a first-line treatment for the common cold. So, it’s safe to assume that sleep has a role to play in recovery. There are five reasons why sleeping for longer may be beneficial:
- Immune-Boosting Sleep – Sleep supports our immune system. If sickness has taken hold, it’s because our immunity was compromised. So, sleeping for longer when you’re sick may help to strengthen immunity, allowing you to heal faster.
- Restorative Sleep – Studies have shown that when we have the flu, we spend more time in slow-wave ‘deep’ sleep. Slow-wave sleep is restorative for the mind and the body, so may speed up our recovery.
- Catch-up Sleep – Viral infections can cause sleep-disruptive symptoms. If your cold keeps you awake one night, you’ll probably oversleep the next. This ‘catch-up sleep’ can prevent a cold from worsening.
- Conserving Energy by Oversleeping – When we are asleep, most of our energy is conserved, so our bodies have more resources available to fight infections. After catastrophic injuries, patients are placed in medically-induced comas to conserve their energy. Our tendency to oversleep when we’re suffering from flu is a similar (more rudimentary) form of energy conservation.
- Oversleeping Caused by a Neurochemical Response – Researchers have found that, when animals are exposed to viruses, their bodies release chemicals which promote stress relief and ‘recovery sleep.’ It’s thought that humans release similar chemicals in response to flu, to induce a lengthy ‘recovery sleep.’
In essence, oversleeping allows your body time to repair itself. Each of these mechanisms will be explored in a little more detail below. Unfortunately, we know that some people find it very difficult to sleep when they’re sick.
Why Do I Sleep So Much When I’m Sick?
As we’ve discussed, it seems our bodies are programmed to need more sleep when we’re sick. However, other factors could contribute to oversleeping. Examples include the following:
- A Change in Schedule – When you’re sick, you often take the day off work, or change your schedule. This reduction in activities makes bed rest and sleep more accessible. The boredom that sets in after watching too much daytime television can also lead to oversleeping when you’re sick.
- Cold and Flu Meds – The ‘drowsy’ chemicals in your cold and flu medication can cause you to sleep for longer. Nighttime cold and flu meds can make some people feel very lethargic, and lead to too much oversleeping. As such, the extra sleep you’re getting might not necessarily be ‘restorative.’
- An Underlying Health Condition – Some people wrongly attribute their oversleeping to the flu. Oversleeping could be caused by sleep apnea, narcolepsy, or menopause.
Nonetheless, in many cases, sleeping for longer will probably aid your recovery. Let’s look at the evidence, to evaluate this claim in a little more detail.
Sleep and Immune Function
Scientists believe that sleep may help to regulate our circulating T and B cells (cells responsible for immunity). A strong immune system can fight disease more effectively. If good quality sleep facilitates better immunity, it’s no surprise that during times of illness we want to sleep more. But what has led scientists to draw a link between sleep, immunity, and disease recovery?
A study published in Sleep Journal found that people who regularly slept less than 5 hours per night were much more likely to contract the common cold. The researchers concluded that a lack of sleep made people more susceptible to illness because it weakened their immune systems.
It follows that, if poor sleep encourages the flu to take hold, oversleeping when sick might help the body to recover. So, if you find yourself sleeping for 10 or 12 hours at a time, your body is probably busy restoring immunity.
As we’ll explore, many lifestyle factors (besides sleep deprivation) can damage immunity. These factors should be remedied if you want to protect yourself against viral infections.
Can Deep Sleep Help You Recover from a Cold?
Each night, our bodies enter four stages of sleep. The length of each stage is mostly predictable and unchanging. However, studies have shown that specific factors can de-regulate the length of our sleep stages. Factors that can alter our sleep architecture include:
- Temperature (i.e., sleeping in a hot or cold environment)
- Medications or stimulants (illegal drugs, antihistamines, alcohol, and caffeine)
- Physical illness (such as the common cold or flu)
Studies have shown that slow-wave sleep tends to increase in duration (stage 3 and 4 sleep). Our slow-wave sleep is very deep, restorative sleep. At the same time, our REM sleep (rapid eye movement) slightly shortens in duration.
In a review published by Nature, scientists predict that this alteration in our sleep architecture is an adaptive process that helps our bodies access deep, restorative sleep. As a result, we can heal faster.
Unfortunately, anything that de-regulates the 4 stages of sleep can cause some people to feel groggy or imbalanced. This may explain why some people feel worse after sleeping when they’re suffering from the flu. Nonetheless, the increase in restorative, deep sleep seems a necessary trade-off to support recovery.
Does Flu Interrupt or Increase Sleep?
To answer this question, it’s vital to distinguish between the ‘incubation’ and the ‘symptomatic’ stage of flu. When you contract the flu, it ‘incubates’ for a short period of time. During this time, the quality and length of your sleep decrease. Once your symptoms arise a couple of days later, you may find yourself oversleeping, because you’ve lost so much sleep during the incubation period.
Incidentally, if you are troubled by a few sleepless nights that you cannot explain, you might be ‘coming down with something.’
The Incubation Stage
The incubation stage is the period of time between catching an infection and symptoms developing. With regards to the flu, the incubation period typically lasts 1-4 days. For a cold, the incubation period is roughly 1-2 days. Studies have shown that while the infection is ‘taking hold,’ you’re likely to experience the following:
- Reduced overall sleep (i.e., less than 5 hours per night)
- Waking up frequently throughout the night
- Feeling lethargic and groggy in the morning
Although you’ll experience disturbed sleep, you might not put this down to having the flu, as the main symptoms of the flu won’t have arrived yet. If the incubation stage lasts four days, that’s four nights of poor quality sleep you’ll need to claw back.
The Symptomatic Stage
This is when the nasty symptoms set in. We’ll explore cold and flu symptoms in a little more detail below, but you can expect fever, body pain, vomiting, and a runny nose. During the symptomatic stage, most people will sleep for a lot longer. This may be because the body needs to catch up on the sleep it has lost during the incubation stage.
It should be mentioned, one study on NCBI found that certain viral infections shortened (rather than lengthened) sleep duration during the symptomatic stage of flu. Perhaps this is evidence to suggest that some people’s bodies respond differently to illness. If you’re finding it difficult to sleep with the flu, you should read on to find out how to get a better night’s sleep.
Why Do I Feel More Tired than Usual?
The sleepiness that arises out of illness is distinguishable from the tiredness we feel after a long day. When we’re ill, we’re overcome with lethargy. But why do we feel so overwhelmingly sleepy? So-called ‘recovery sleep’ may be an inbuilt biological response to viral infections.
As a response to cellular stress, our bodies release certain chemicals which induce ‘recovery sleep.’ Cellular stress can be caused by a wide range of factors. These include:
- Sunburn or frostbite
- Viral illness (cold and flu)
- Physical injury
- Being poisoned with toxic substances
According to a recent study, roundworms release a chemical known as FLP-13 when they are exposed to viral infections. FLP-13 caused the worms to sleep for longer – presumably to aid recovery. It is believed that chemicals very similar to FLP-13 are released by humans when they’re infected with viruses, though scientists do not fully understand the relationship between sleep, illness, and recovery in humans.
Scientists predict that some people release more chemicals than others – in response to illness. This may explain why some people get a lot of ‘recovery sleep’ and others struggle to get the bare minimum. In time, scientists may be able to develop medications that can improve this mechanism, so that everyone can benefit from lengthy ‘recovery sleep.’
Can I Get the Same Benefits from Rest?
Some doctors tell us to get more sleep, whereas others focus on the importance of ‘rest.’ So, can rest be as effective as sleep for promoting recovery?
Taking rest is beneficial because (like sleep) it can help preserve your energy. Unlike oversleeping, rest may enable you to preserve your energy without feeling groggy. Also, rest promotes stress relief which will support the immune system.
Evidence suggests that people respond to illness in different ways. Some people need to sleep during the day when they’re ill. Other people can skip the afternoon naps and still recover quickly – as long as they take it easy throughout the day.
Although people respond to illnesses differently, you should never try to exercise a virus away. According to Trib Live, it’s a common misconception that you can ‘sweat out’ the flu in the gym. Working up a sweat is the worst thing you can do because your body is more susceptible to viruses after an intensive workout.
Drowsy Medication and Oversleeping
Cold and flu meds often contain ingredients that make us feel drowsy. These ingredients may cause us to oversleep. Can drug-induced sleep promote recovery in the same way as biologically-induced ‘recovery sleep’ can? The jury is still out on that one. Nonetheless, if you’re finding it very difficult to drop off to sleep, nighttime flu medication could be a great option.
One of the key ingredients in nighttime flu medication is Diphenhydramine. This ingredient is an antihistamine that relieves a runny nose. It is also a mild sedative so may encourage deeper, less disturbed sleep. Some people find ‘drowsy’ medication comforting and helpful, but others feel groggy when using it. Often, it’s a process of trial and error to see what works best for you.
Can Too Much Sleep Make a Cold Worse?
In general, oversleeping is associated with many adverse health outcomes, including:
- Cardiovascular issues
- Psychiatric conditions
However, given that the oversleeping associated with a cold is temporary, we can’t draw the same conclusions. The only real issue to be concerned about is dehydration.
If you are sleeping for 10 or 12 hours at a time, you will probably become very dehydrated. Staying hydrated is one of the best ways to rid your body of illness so make sure you keep a glass of water close to your bedside.
How Much Sleep Do I Need When Sick?
There are no hard and fast rules when it comes to sleep and illness. Healthy individuals are recommended 6-8 hours per night, so you should aim for at least this amount.
If you are suffering from influenza (as opposed to the common cold), you’ll probably need quite a lot more than 8 hours of sleep. According to the authors of ‘The Science of Sleep’ people suffering from a bad case of the flu often sleep for 12 hours at a time.
When you’re ill, you might find yourself napping throughout the day. There’s nothing wrong with napping. However, if you can sleep for at least 4 hours at a time, you’re more likely to get the ‘restorative’ benefits of sleep. If you’re struggling to ‘sleep through’ at night, try limiting your daytime naps so that you can get better quality sleep at night.
How to Sleep Better with a Cold or Flu
We’ve discussed the potential benefits of sleep, but what if you’re struggling to access these benefits? As mentioned, some people do experience insomnia alongside illness. It’s no wonder when you consider the many symptoms you have to deal with.
Both the common cold and flu are viral infections. However, the flu tends to come on more suddenly and is much more debilitating than the common cold.
Symptoms of a Cold
- A Runny nose
- A Sore throat
- A Light headache or nausea
Symptoms of Flu
- A dry cough
- Aches and pains
- Complete loss of appetite
Symptoms of the flu can be nastier and potentially more disruptive to sleep. Ironically, it’s flu sufferers that need sleep the most! Follow these tips to get a better night’s sleep when you’re ill:
- Clear Your Schedule –If you have the flu, don’t even think about going to work or meeting friends; now is the perfect excuse for a duvet day (or two). It’s imperative to avoid any source of stress, as this could further impair your immune system and delay recovery. If your mind is free of stress, you’re more likely to sleep soundly.
- Take Cold/Flu Medicine – Coughing is likely to disturb your sleep, but a cough treatment can prevent this. Alternatively, a decongestant may be helpful if you’re suffering from a blocked nose. Also, pain medication such as paracetamol can help dampen any aches and pains, helping you to feel more comfortable in bed. As we’ve discussed, it is up to you whether you try a drowsy or non-drowsy formula.
- Ventilate Your Bedroom – If you’ve got a high fever and shivers, it can be hard to know what temperature to pitch your room at. It’s good to encourage a free-flow of air because this will prevent bacteria from stagnating. Pile some blankets at the end of your bed so you can ‘layer up’ when you start to feel cold.
- Hydrate Yourself – If you’re finding plain water a chore, add some cordial or fresh lemon to the water to make it more palatable. If you’re struggling to stay hydrated, some rehydration salts (or a salty broth) could help you feel better. You’re more likely to ‘sleep through’ if you go to bed hydrated.
Should I See a Doctor?
Oversleeping when you have the flu could be coincidental; it may indicate an underlying health concern. For example, narcolepsy or sleep apnea could be responsible for excessive sleep habits.
If you notice any extremes in your sleeping behaviors, you should see a doctor. We know that it is normal for flu sufferers to sleep for up to 12 hours, but if this continues for many days (or increases) you should see a doctor. Similarly, if you’re unable to get more than 4 hours of sleep, for 4 consecutive nights, you should see a doctor. There are certain categories of people that are ‘high risk’ flu sufferers. These include:
- Pregnant women
- Older people over 65
- Anyone with a severely weakened immune system
- People with lung or kidney disease
If you fall into one of these categories, you’ll probably find you’re sleeping even more than an average flu sufferer. If you are in the high-risk category, you should always see a doctor for specialist treatment.
How to Prevent the Common Cold
Approximately 250 different viruses are responsible for causing the common cold. We’re all susceptible so we should all take steps to prevent this infection. Prevention methods fall into two main categories.
Firstly, we can improve our hygiene, so we’re less likely to come into contact with a virus (remember, viruses that cause the common cold are highly contagious!). Secondly, we can boost our immunity, so we’re less likely to surrender to a cold.
How to Boost Immunity to Prevent a Cold
- Reduce or quit smoking
- Limit alcohol intake
- Manage stress effectively
- Eat a varied diet, rich in vitamins and minerals
- Consider zinc and echinacea Supplements
- Consider probiotics
- Take regular, moderate exercise
- Supplement vitamin D if you live in a cold climate
How to Prevent Virus Contamination
- Wash your hands regularly, and always after using the bathroom
- Keep your hands away from your face (especially your mouth)
- Disinfect communal surfaces regularly (think: light switches, fridge and door handles, phones and worktops)
- Do not share your towel
- Ventilate your home and workplace
Also, some people opt for an annual flu jab to protect themselves against viral infections.
Should I Sleep More When I’m sick?
To answer this question, let’s summarize what we’ve discussed in this guide. Sleeping for longer is likely to improve a cold because it boosts our immunity, conserves our energy, and helps us forget about our symptoms. So, listen to your body; If it’s telling you that you need sleep, you probably do.
As we’ve discussed, people may respond differently to viral infections. Some people seem to thrive on ‘rest’ rather than excessive sleep. As such, there are no hard and fast rules regarding the exact amount of sleep you require when you’re ill.
If you want to turbo-charge your recovery, make sure your extended periods of sleep do not cause you to become dehydrated. Also, try to take steps to boost your immunity. This should help you recover faster and prevent colds from returning in the future.