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Think and Grow Healthy: How Positive Emotions Can Protect You From The Common Cold

by Mark Dhamma
Home/Blog/Protect Your Mental Wellbeing During the COVID-19 Pandemic

Could the way we think affect our physiology? Here’s an easy test that you can do right now:

Think of something that really frightens you; maybe a scary movie you’ve seen. For some of us, public speaking causes fear. Perhaps for you, the scariest thing you can think of is being forced to eat high-sugar junk food with a hearty dose of gluten!

Notice when you think of something really scary that your heart rate increases slightly, you may tense your muscles in your face, the breathing becomes more shallow and at a faster rate.

Your thoughts have just changed your physiology.

Now, is it so much of a stretch to now think that perhaps that our thoughts can directly impact our health too? There’s mounting conclusive evidence that they do. Research has shown that our conscious thoughts are linked to cardiovascular disease, mortality and even cancer risk [2,3,4]. Surprisingly, one of the most understood effects is how positive emotions affect our immune system.

Your Thoughts and the Common Cold

Ask yourself, how long do your common colds last?

For some people, colds last only a couple of days, but for many others they can last up to three weeks. Some people seem to never get colds and others get multiple colds per year. Could how you think affect how many colds you get and the length they linger?

Of course, it’s common sense that depressed people tend to complain more about colds, more than happy people who choose not to focus on the negative aspects of how they’re feeling. Due to this, for many years researchers assumed that being happy or sad doesn’t actually affect the severity of the cold, it just affects how people report on how the cold is affecting them. However, between 2003 & 2006, Dr. Sheldon Cohen at Carnegie Mellon University had a series of studies [1] which concluded that your emotional states are a significant factor on whether you contract the common cold and how long it will last. Cohen recruited large numbers of healthy volunteers and they were first interviewed and observed nightly for seven nights. From these interviews, the average mood was documented, positive or negative. Positive emotion consisted of the interviewer and observer rating the volunteer as being “full of pep,” “energetic,” “happy,” “at ease,” “calm,” and “cheerful.” Negative emotion consisted of “sad,” “depressed,” “unhappy,” “nervous,” “hostile,” and “resentful” ratings. The ratings are of the volunteers actual emotional states.

After 7 days of observation, all of the volunteers got rhinovirus (the common cold) squirted into their noses and were kept under observation and in quarantine for six days to let the cold develop. Physiological measures of the cold such as mucus production and congestion were studied. Additionally, volunteers gave reports on how they were feeling. The findings showed that people with high positive emotion before the rhinovirus develop fewer colds than people with average positive emotion, who in turn get fewer colds than people with low positive emotion. The effect works both ways, with high positive emotion strengthening volunteers compared to average, and low positive emotion weakening volunteers compared to average.

How does positive emotion reduce colds?

Since the volunteers were kept in quarantine and closely observed, differences in sleep, diet, cortisol, vitamin levels, and exercise are ruled out. The key difference is interleukin-6, a protein that causes inflammation. The higher the positive emotion, the lower the interleukin-6, ergo less inflammation [5]. Sheldon replicated this study with flu virus as well as cold virus, with the same results: positive emotion is the driving factor.

How to Increase Positive Emotions

An exercise to increase positive emotions that I use for myself and with my clients is tospeak out loud at least 3 things you can be grateful for each day. Gratitude has been studied in Positive Psychology literature, has been shown to increase positive emotions, and decrease depressive symptoms, among other benefits [6].

The exercise is simple to do and simple to understand. As soon as possible after waking up, say out loud 3-10 things that you can be grateful for in your life. Maybe it’s a loved one, your health, your career, your intelligence, whatever is meaningful for you. The key to this exercise is to be creative and come up with new observations on what you can be grateful for. Allow yourself to feel the positive emotions that gratitude creates for you.

Doing this exercise in the morning has a double benefit. Not only does it build positive emotions to to make you feel good and likely reduce inflammation, it also primes your mind to focus on more things you find throughout the day to further increase positive emotions!

More and more research shows that our thoughts do indeed affect our health. It’s important to be just as aware of our thoughts as we are of diet and exercise. This is an exciting time to not only learn how to improve our mental health but also to improve our physical health. Perhaps taking our gratitude practice and levels of optimism as seriously as we take our diet, exercise and recovery, could unlock new levels of well-being for all of us.

Feeling pessimistic? In my workshop at Paleo f(x)™ 2016, I will be teaching you  how to be optimistic to protect yourself from heart disease. Hope to see you there!


  1. S. Cohen, W. J. Doyle, R. B. Turner, C. M. Alper, and D. P. Skoner, “Emotional Style and Susceptibility to the Common Cold,” Psychosomatic Medicine 65 (2003): 652– 57.
  2. H. Tindle, Y. F. Chang, L. Kuller, J. E. Manson, J. G. Robinson, M. C. Rosal, G. J. Siegle, and K. A. Matthews, “Optimism, Cynical Hostility, and Incident Coronary Heart Disease and Mortality in the Women’s Health Initiative,” Circulation 118 (2009): 1145– 46.
  3. E. Giltay, J. Geleijnse, F. Zitman, T. Hoekstra, and E. Schouten, “Dispositional Optimism and All-Cause and Cardiovascular Mortality in a Prospective Cohort of Elderly Dutch Men and Women,” Archives of General Psychiatry 61 (2004): 1126– 35.
  4. H. Tindle, Y. F. Chang, and L. Kuller, et al., “Optimism, Cynical Hostility, and Incident Coronary Heart Disease and Mortality in the Women’s Health Initiative,” Circulation 10 (2009): 1161– 67.
  5. W. J. Doyle, D. A. Gentile, and S. Cohen, “Emotional Style, Nasal Cytokines, and Illness Expression After Experimental Rhinovirus Exposure,” Brain, Behavior, and Immunity 20 (2006): 175– 81.
  6. Wood, A. M., Froh, J. J., & Geraghty, A. W. (2010). Gratitude and well-being: A review and theoretical integration. Clinical psychology review, 30(7), 890-905.
Positive Thoughts photo licensed under the Creative Commons.


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Mark Dhamma

Mark Dhamma has been studying high performance health and psychology for 17 years.