There’s no ifs-ands-or-buts about it. Traveling kicks our immune system’s butt- I should know! This is my third time being sick in two months since we began our world traveling adventure. This isn’t new information though. Most of us who have traveled know to start taking those pre-trip vitamins at least a day or two before a big trip to boost our immune systems and Airborne isn’t worth over 1 billion dollars for no reason. We have all heard theories (sharing stale re-used air on an airplane) or speculated (increased exposure to germs and sick people) as to why travel increases our likelihood of getting sick but what does research/evidence based information have to say about it? What are the ‘hard facts’ and why we are more likely to get sick when we travel? Some (if not all) of these will not surprise you (and you may even smuggly get to say to yourself, or anyone who will listen, that you were right all along) while others may inform, if not, intrigue you. I know I had fun getting to the bottom of this issue once and for all!
Big surprise here, but the closer you are to other people and their germs, the more likely you are to catch a bug yourself (go figure!). And with the ever shrinking seats in today’s planes that means we are closer together and sharing our germs more than ever with our fellow sardines.
Less sleep = higher likelihood of getting sick
Again, not a shocking revelation but what surprised me was HOW much more likely. In two separate studies looking at this issue both concluded an increased risk in illness. In the first study conducted in 2009, those reporting getting less than 7 hours of sleep consecutively over the course of 14 days, were 3 times as likely to get sick when exposed to a cold virus than those getting their full 8 hours (lucky bastards!). Similarly in a more recent study conducted in 2015 it was reported that those study participants who got less than 6 hours of sleep a night over the course of 7 days were 4 times more likely to report cold symptoms and the likelihood increased again for every hour of less sleep. Unfortunately, when traveling, disruption of sleep and your sleep schedule is often par for the course (hey look, I used golf lingo correctly! Awesome!), especially when traveling across time-zones or at odd hours (like taking a red-eye flight or twilight train ride to save some money). Changing and/or messing with the body’s circadian rhythm is rough on the whole system and can leave it (and you) out-of-whack for a while as it readjusts.
Stress is your body’s worst enemy
For those that think traveling to some far off destination and enjoying long-term adventuring can’t be stressful, think again. Although there are a LOT of wonderful aspects of traveling and long-term adventuring, when travel is your life it is also your job which has stresses like any other aspect of life and work. Researching locations, budgeting, figuring out all the details, arranging transportation and accommodations, packing up your life and then doing the traveling itself (often in a foreign country and language) is hella stressful! And doing this multiple times a month only adds to the workload and inevitable stress. But why is stress so toxic and how exactly does it impact the immune system? Well, when we are stressed our kidneys releases a hormone called cortisol which kick’s in our body’s ‘fight-flight-freeze’ response. Another interesting thing cortisol does is it shuts off the body’s inflammatory response (immune system) while it is redirecting functioning to ‘fight-flight-freeze’ mode. Unfortunately, when we experience on-going stress (as many who are preparing to travel and then traveling do) this response doesn’t shut off which means our body is being flooded by cortisol and our immune system remains suppressed making it harder for it to fight off infections and viruses.
What do we do?
So now that we have all this helpful information, the question that naturally follows is, what can we do to be healthy and prevent illness when traveling? Read Part II in this series to get your healthy travel tips.
Besedovsky, L.; Lange, T.; & Born, J. (Jan, 2012). Sleep and immune function. Pflugers Archiv: European Journal of Physiology. 463 (1): 121-37. Kiecott-Glaser, J.K.; McGuire, L.; Robles, T.; & Glaser, R. (2002). Psychoneuroimmunology: Psychological influences on immune function and health. Journal of Clinical Psychology. 70: 537-547. Irwin, M.R. (Jan., 2015). Why sleep is important: A psychoneuroimmunology perspective. Annual Review of Psychology. 66: 143-72. Lange, T.; Dimitrov, S.; & Born, J. (April, 2010). Effects of sleep and circadian rhythm on the human immune system. Annals of the New York Academy of Sciences. 1193: 48-59. Merez, B. (Sep. 8, 2016). Resetting your circadian clock to minimize jet lag. Harvard Women’s Health Watch. Retrieved from, http://www.health.harvard.edu/blog/resetting-your-circadian-clock-to-minimize-jet-lag-2016090810279 Popular Science (Sep. 14, 2016) Why We Always Get Sick While Traveling- And How to Prevent It. Retrieved from, https://www.popsci.com/why-we-always-get-sick-on-road-and-how-to-prevent-it Prather, A.A.; Janicki-Deverts, D.; Hall, M.H.; & Cohen, S. (Sep, 2015). Behaviorally assessed sleep and susceptibility to the common cold. Sleep. 38(9): 1353-9. Zitter, J.N. (Dec. 18, 2002). Upper respiratory tract infections among airline passengers. JAMA. 288(23): 2972.