[Coronavirus Update] The importance of sleep to survive a viral infection

Written by Denise Tam, Holistic Nutritionist

March 3, 2020

The key to surviving a viral infection like the Coronavirus is having a strong immune system.

In my first article back in January on the Top 10 Defense Strategies for the Coronavirus, sleep was one of the top tips I recommended to keep our immunity strong. This article will unpack why and give brief tips on how to improve our sleep.

Infection process

In Part 1 of How to Minimize your Chance of Being Infected, I explained how the actual virus infects and enters our cells through different receptors like ACE2 and the furin protein. Once it enters our cell, the virus releases the DNA or RNA, in the case of the Coronavirus it is RNA, then the cell unknowingly follows the instructions from the RNA and makes more of this virus within the cell. And from there the cells explode to release new viruses into the body and the infection cycle is repeated and spread throughout the body unless contained. 

Extended Reading:

If our immune system doesn't get onto the virus quickly and quarantine them then it will cause more infection and a wider infection. And this is why the key to surviving a viral infection like the Coronavirus is having an immune system that is optimally, if not perfectly. 


According to a JAMA study on Characteristics of and Important Lessons From the Coronavirus Disease 2019 (COVID-19) Outbreak in China, unlike SARS and MERS where the spread was mainly within the hospital, “it appears that considerable transmission is occurring among close contacts [for COVID-19]”. As a result, COVID-19 has led to more total deaths [than SARS and MERS] due to the large number of cases.

The JAMA study also reported :
  • 81% of cases are mild (non pneumonia symptoms)
  • 14% of cases are classified as severe (symptoms of : shortness of breath, low blood oxygen level)
  • 5% of cases are critical (use of ventilators etc)

And a very promising and encouraging finding of “no death in mild and severe cases” However, the case fatality rate was 49% in critical cases and those with pre-existing comorbidity conditions like cardiovascular and diabetes increased their CFR by 10% and 7% respectively.

So even if COVID-19 is a pandemic, and even if we are infected, the likelihood of recovering from it would be high if you do not fall into the other categories of pre-existing conditions and old age (over 80). This is exactly why having a strong immune system is important. 

sleeping is important for immune system

Apart from ensuring your diet and nutrients are in balance and you are getting sufficient immune boosting nutrients, one of the biggest things you can do for any viral infection is sleep. There are peer reviewed papers and extensive research of sleep on your immune response against viruses.

One study shows, quality is just as important as quantity when it comes to sleep. That 7-9 hours night is crucial for immunity, but the quality of sleep is also important. Between 10pm -2am  is when we have our slow wave deep sleep and this is when our body does the most restorative work and healing

So if we’re not getting our slow wave deep sleep, we are missing out on the production of growth hormone that affects our immunity and healing. In Hong Kong, sleeping at 12am  is already considered early and so at best you are getting maybe just one hour of that slow wave deep restorative sleep.

How do you know if you are sleeping well?

You can use different devices that help track your sleep. I’ve been using the Oura ring that tracks when I sleep, how well I sleep and how long I spend in my deep, light and REM stages of sleep as well as latency.

sleeping tracking

This other study showed just how detrimental sleep deprivation is on our immune system and did a study on 25 subjects who had approximately 8 hours of sleep consecutively for 7 days versus another group who had sleep deprivation of about 4-6 hours of night for 7 nights and were then able to recover from their sleep deprivation with 12 hours of sleep, those who were sleep deprived reduced their ability to fight off the flu by more than half compared to those who had enough sleep. And it took them around 30 days for their immune system to go back to ‘normal’. What would be interesting to know is the length of ‘recovery’ for those with chronic sleep deprivation, which many of us in Hong Kong have.

One last study to show the importance of sleep on immunity shows that 7 hours of sleep or less makes you about 3 times more likely to get a cold. Also sleep efficiency (the amount of time that you are asleep divided by the time you are in bed) of less than 92% (this is where a device like the Oura ring comes in handy), makes you 5.5 times more susceptible to getting a cold. No other factors like your weight, BMI, race and even flu season affected it as much as sleep efficiency and duration. 

Just in my circle alone, more than half of the people do not sleep well. Whether it’s insomnia, sleep apnea, anxiety, etc, it is important to address the sleep issue. Somehow as humans, we have decided on our own that it is okay to run on less sleep, but in reality it is taking a toll on our bodies. Insomnia is a very cruel thing, I’ve been there, during my chemotherapy treatments. I encourage you to work with a functional medicine practitioner to get to the root of the issue. 

Tips for better and more effective sleep: 

1. Set your circadian rhythm by going to bed at set times, preferably already have fallen asleep by 10pm or 11pm latest to get as much deep restorative sleep as possible.

2. Upon waking, expose your eyes to natural sunlight as early as possible to start your melatonin production. It takes around 12 hours for melatonin to reset, so the earlier you expose yourself to sunlight the earlier your melatonin will kick in at night. Melatonin is the hormone we produce to tell our bodies to go to bed.

3. Limit your exposure to blue light that can keep you awake and cause too much stimulation, raising your cortisol levels

4. Control cortisol levels using contemplative exercises like journaling or herbs like ashwagandha or holy basil

5. Lower your room temperature as study shows better sleep is achieved in a cooler environment. 

6. If you’re looking to recover from sleep deprivation, cheat your way into a deeper restorative sleep by dosing on 10-12mg melatonin so you can recover faster and reset your clock quicker 

7. Utilize natural relaxants and anti stress nutrients like magnesium, B complex, GABA or even something simple like sea salt with water in the morning to help offset the demands on your adrenals. Please work with your health care provider when adding in supplements to your routine. 

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