Once, Twice, Three Times… Less Likely to Get a Cold

In the past, we’ve highlighted the importance of sleep in our lives as evidence mounts. A healthy amount of the stuff can help with memory, and a study showing that those who toss and turn to the tune of five or fewer hours of sleep per night have a higher incidence of “silent” heart disease suggests its importance in cardiovascular health. But it’s not like we needed science to tell us that getting plenty of sleep was good for us; the sluggish thoughts, rotten moods, and general uselessness we experience on inadequate sleep is our body’s way of telling us to sleep more and sleep better.

Still, we’re suckers for a good scientific study that further clarifies our Primal way of approaching the world, so we need to add just one more pro-sleep study to the pantheon of research we’ve already related (okay, there’ll probably be way more coming in the future, we can’t lie). Dr. Sheldon Cohen of Carnegie Mellon recently helmed a study examining the relationship between sleep and viral immunity, specifically immunity against the common cold virus. For fourteen days, the sleep patterns of 153 men and women were monitored, recorded, and analyzed (they didn’t just monitor how long someone was in bed, but rather actually recorded each patient’s sleep efficiency, or how many hours they actually slept). After fourteen days, drops of rhinovirus (which causes the common cold) were administered to the nasal cavities of the patients. Each person was monitored for the day prior to and five days after the administration of the virus.

People getting less than seven hours of sleep per night were almost 3 times as likely (2.94, to be exact) to develop a cold than those getting the recommended eight hours or more per night. Sleep efficiency was even more telling – those patients with less than 92% efficiency (in other words, for less than 92% of the time in bed, they were actually sleeping) were 5.5 times more likely to catch a cold.

We don’t want to overstate this, though. Just cause you miss a few hours of sleep doesn’t mean you’re sure to catch a cold, nor does it mean you’re going to suffer from heart disease or be unable to remember to pack a lunch. But if inefficient or inadequate sleep is a regular part of your life, you should be aware that you’re compromising your health.

Adequate sleep is, in our opinion, actually one of the toughest aspects of the Primal Blueprint to keep up with. Sure, Grok didn’t have rush-hour commutes to avoid, kids to pick up from soccer practice, or looming deadlines; he merely had to have enough food and shelter to survive for the day, no easy task. He lived a hard-scrabble life, where food was never guaranteed and danger lurked around every corner – but he was still able to find time for rest and relaxation. Meanwhile, our hard-scrabble lives are artificial. Man-made. Most of us have plenty of food, live in homes that can withstand thunderstorms and earthquakes, and have soft beds, but we make our lives more difficult than they need to be. We’ve replaced natural dangers with dangers and stresses of our own creation.

By all means, wake up early to beat traffic, spend plenty of time with your kids, and excel at your job… just don’t forget about yourself. Sneaking in a couple extra hours of sleep per day might be difficult for many of us, but the potential benefits are worth the effort.

Further Reading:

Top 10 Ways to Make it Through the Flu Season

Good Night and Good Health

Insomnia Sleep Tips

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14 thoughts on “Once, Twice, Three Times… Less Likely to Get a Cold”

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  1. A very important thing to get better sleep is to cut yourself off from as much modern gadgets as possible at the right time. If I only have the lamp and a book I dose off easily, but if I ever leave a movie on, or stay online it can get pretty tough to get some good sleep.
    Moreover, the reasons you mentioned are exactly why I will do everything I can to be able to work less. While it may seem that success depends on long hours and tirelessness, I always remember Steven Spielberg: works 9-5 without hardly ever any overtime. My dad told me once that the more he works the less he’ll make, and that is what I will strive for in my life: work hard to work less.

  2. That is a good post. It reminds me of Erwan Le Corre’s thoughts
    about us being “zoo humans” who need to escape and recover our natural way of life.

    I interview Erwan here:


    “The zoo is not just an environment, it is a phenomenon, a process, which is designed to keep you captive of both external and internal cages. It is something that conditions many of your behaviors, so clearly it is to me a domestication system, no less. The zoo impairs our ability to experience our true nature which is to be strong, healthy, happy and free.”

  3. Of course it’s possible that the people getting the poorer sleep also had other lifestyle factors contributing to their immunity – for example, perhaps when you feel tired you are more likely to eat bad food… Of course I would say this because whilst I am able to control all the other things in my life to be as primal as possible, sleeping is a lot harder to control and I often have little success! That said, I have had only 2 colds in 6 years…

  4. My sleep didn’t change much, but I have not had a cold since Feb 2008 when I went “Primal”. The lifestyle you prescribe has drastically improved my immune system. “Normally” I would have had 2-3 colds during that same time frame.

  5. I think it’s important to point out as many studies as possible when it comes to getting more sleep. It is one of the most underrated behaviors of healthy people and it should be in the forefront of our minds when it comes to living a healthy life.

    I use to be able to sleep for 12 hours or more, but these days, it seems like I end up waking myself up around the 7 hour mark. I’ve been trying to shoot for an extra hour, but it takes fine tuning your habits to make it work.

    Thanks for the post!

    All the Best,

    Andrew R

  6. I am proud to report that this winter so far (my first primal winter), I have not yet gotten sick. That is a first in a very long time.

    The SoG

  7. Great post Mark. I think as you say most people are fully aware of the benefits of consistent, quality sleep but scientific studies drive the message home even further. I myself have noticed that if I fail to get enough sleep a few days on the trot I start to feel really run down and get a runny nose.

    However, it is really hard to make yourself sleep the required amount. There just seems to be so many things to fit into the day and not enough hours to do them. Once I get in bed I generally don’t have trouble falling asleep. It’s just very difficult to make yourself get in bed at a reasonable hour.

  8. Sleep is so important and without a clear mind I cannot get my 7-10Hrs in. Recently I have found even if I am sleepy going to bed if I have an unresolved issue on my mind before hitting the sack I will always wake up with a busy mind stopping me from getting back to bed and keeping me up until the morning…..
    A great way to avoid this is simply to keep a notebook in which you write down all your worries, things to do and other tasks before you sleep, then tell yourself that you’ll deal with them later. Works wonders….

  9. I used to be able to sleep a solid 8 hours or more but ever since I’ve started eating “better” (more paleo, minimal dairy, etc.) and fasting intermittently, I’ve found that I can’t sleep more than 5-7 hours a night. Also, I notice that I sleep deeper and wake up feeling more refreshed than before. So I’m assuming that the 8 hours is NOT a hard and fast rule for everyone?

  10. I love to sleep and i do get what i need.
    8 hours sleep, eating healthy foods, exercising, take a good supplement such as Damage Control Master Formula. This is what i do and i never get winter nor summer colds, this works for me!

  11. “but we make our lives more difficult than they need to be. We’ve replaced natural dangers with dangers and stresses of our own creation.” – might be one of the best lines you have ever said Mark!

  12. I had a hard time believing in this, even with the scientific proof, until I started sleeping more and sleeping better.
    I can attest to its benefits. (knocking on wood) I believe my year being cold -free is a direct result of my change in sleeping habits.
    Thanks for sharing.

  13. I had my flu last week. I was sleeping badly and I got run down,and next thing I was bunged up with a nasty flu.