Top Line

Sleep is an essential component of our daily lives and how much sleep we get a night can be the difference in whether or not we protect ourselves from disease or viruses.

Why it Matters

If we get good quality sleep, we allow our immune system to function properly. If we get poor quality sleep, we suppress our immune system. Making us vulnerable against diseases and viruses.

Key Takeaways

• Chronic lack of sleep can increase your risk of upper respiratory tract infections (URTI).^1,2
• Lack of sleep may reduce the effectiveness of vaccines.³
• Improved sleep quality is associated with a reduced risk of infection, and can improve infection outcome and vaccination responses.⁴

Article:

Sleep is an essential component of our daily lives and how much sleep we get a night can be the difference in whether or not we protect ourselves from disease or viruses. This is because sleep and our immune system have a bidirectional relationship. In other words, if we get good quality sleep, we allow our immune system to function properly. If we get poor quality sleep, we suppress our immune system. Making us vulnerable against diseases and viruses.

A suppressed immune system will start to manifest itself from a chronic lack of sleep which can lead to systemic low-grade inflammation.⁵ This chronic lack of sleep can increase your risk of upper respiratory tract infections (URTI). ^1,2 For example, those who average less than 5-6 hours of sleep have a 30-45% risk for catching the common cold or a viral infection. That is a 10-25% higher risk compared to those who average more than 7 hours of sleep. This is regardless of environmental factors or health practices.⁶ See Figure 1 below.

Figure 1. Sleep duration (measured by wrist actigraphy) averaged over a 7-day period before virus exposure is associated with percentage of participants who subsequently developed a cold. The percentage of colds is based on predicted values (adjusted for age and pre challenge viral-specific antibody levels).⁶

On top of that, lack of sleep reduces the effectiveness of vaccines. ³ Now that vaccines are beginning to be distributed for Covid-19 you will want to make sure you are prioritizing the right amount of sleep. This will increase the effectiveness of the vaccine instead of inhibiting it in any way.

The good news is that getting good quality sleep is something you can control. Even better news is that improved sleep quality is associated with a reduced risk of infection, and can improve infection outcome and vaccination responses. ⁴

Below is a chart of the National Sleep Foundation recommendations for the average amount of sleep one should get based on their age group:

Newborns (0-3 months)	14-17 hours each day
Infants (4-11 months)	12-15 hours
Toddlers (1-2 years)	11-14 hours
Preschoolers (3-5)	10-13 hours
School age children (6-13)	9-11 hours
Teenagers (14-17)	8-10 hours
Younger Adults (18-25)	7-9 hours
Adults (26-64)	7-9 hours
Older Adults (65+)	7-8 hours

*Sourced from: Sleep Foundation

If you find yourself falling short of the recommended sleep time based on your age group, do not worry! There are many things that are within your control that you can implement immediately to improve your sleep quality.

First, here are some things to be aware of that might be inhibiting your sleep quality:

• Blue light
  • Artificial light after sunset can trick your mind into thinking it is still daylight out and inhibit the production of melatonin which triggers your body’s sleep process.
  • If you use your laptop or tablet for 2 hours before bed, it can blunt melatonin output by a whopping 23 percent.⁷
• Caffeine
  • Blocks the buildup of adenosine (sleep pressure) by binding to the adenosine receptors. Adenosine is needed to induce sleep, the more adenosine, the more sleep pressure you feel and will want to fall asleep.
  • Melatonin only signals the initiation of the sleep process which adenosine is a part of. By suppressing adenosine, you reduce the production of melatonin.
  • The effects of caffeine peak 30 minutes after consumption and has a half-life of 5-7 hours. So, if you consume caffeine later in the day it is most likely still in your system when it comes time for you to go to sleep.
• Foods & Alcohol
  • The below foods contain tyramine which increase the production of noradrenaline, which increases brain activity and prevents you from relaxing and beginning the sleep process:
    • Bacon, cheese, chocolate, eggplant, potato, sauerkraut, sausage, spinach, tomato, and wine should be avoided at dinner. This is dose dependent
  • Alcohol consumption reduces REM sleep. Your dream sleep and the cycle of sleep that helps you control your emotions, retain your memory, and more.

Now, here are some things you can implement right away to help offset all of the above:

• Limit blue light exposure at least 2 hours before going to bed. Using apps like f.lux will allow your computer screen to automatically cut out blue light when the sun goes down. There are also blue light blocking glasses from companies like Swanwick that you can wear at night to help limit overhead lighting, tv light, etc.
• Take naps 6-8 hours after waking up. Studies show that naps can improve memory and reverse performance inhibiting effects.
  • Naps should ideally be no longer than 20 minutes. Taking longer naps can make it harder to fall asleep at night. Especially if naps are taken later in the day at like 3 or 4 pm.
• Avoid caffeine after 1 or 2 pm.
  • Unless you are a fast caffeine metabolizer, this could be extended to 3 or 4 pm.
    • For example, the CYP1A2 and AHR gene affects how your body metabolizes caffeine. A CYP1A2 with a T variant is associated with consuming more caffeine and the AHR gene with a C variant is associated consuming more caffeine.
    • Genetic testing from companies like 23andMe will reveal this.
• 20-30 minutes of daily exercise helps balance your circadian rhythm and improve sleep quality.^8,9

The goal is to start with one area you struggle with most and consistently apply one of the above strategies. For example, if you consistently have trouble falling asleep and realize that you are consuming caffeine past 2 pm try avoiding caffeine after 2 pm for a week or two and see if that improves your sleep quality. If it does, stick with it and then begin to work on other areas like limiting blue light exposure and so on.

Now that you got a little more insight into how important sleep is and the benefits it provides to your health, what do you think is the single best thing you can do to improve your health? Hint: It is not just sleep.

Jon Esposito MA, CSCS, CISSN, USAW