Planes, Trains & High Blood Pressure?

Originally published in the National Post, May 17, 2011.

The Hollywood films Up in the Air and Planes, Trains and Automobiles provide two different portraits of the business traveller. The second movie has the John Candy character of Del Griffiths, a beer-swilling, chain-smoking shower curtain ring salesman who doesn't have a home for the holidays. The first movie has George Clooney's Ryan Bingham, who brags about the 320 days per year he spends on the road, and the 350,000 air miles the trips accumulated for him.

Clooney's character seems healthy; Candy's was a mess. Which one better reflects the reality of the business traveller? I have seen both types of business travellers in my practice. Results from two recent studies present an apparent paradox on the health effects of business travel. To investigate the paradox, a colleague and I visited Boston last week to announce a new study on the health of business travellers at the International Society of Travel Medicine Scientific Meeting.

First, let's examine what's already out there. One study, published in the Journal of Travel Medicine in 2010 by researchers at GlaxoSmithKline, surveyed 13,409 employees of an American multinational corporation about their business travel experience and health status. Researchers broke down the respondents into groups based on the frequency and duration of travel. Overall, the 2,962 international travellers tended to have lower body mass index results as well as lower blood pressure compared to the 9,980 nontravellers. However, the travellers also drank more and slept less. The results of this survey show international travellers were the Ryan Binghams of the frequent-flyer lounge.

The second study by Columbia University, published just last month in the Journal of Occupational and Environmental Medicine, examined medical questionnaires belonging to 13,057 clients of EHE International, a New York-based corporate wellness firm. The questionnaire asked patients to rate their present health in terms of excellent, good, fair or poor. Patients also listed how many nights per month they were away from home. The interesting thing about this study? Extensive travellers were more likely to self-report poor health and obesity compared with medium or light travellers. They also had worse clinical examination results for blood pressure, cholesterol and glucose. In this study, the extensive travellers were the Del Griffiths of the frequent-flyer lounge.

Do the study results contradict one another? Business travellers can't simultaneously be John Candy and George Clooney. Reading into the studies a bit may provide some answers.

The GlaxoSmithKline cohort of travellers probably didn't travel as much as the cohort from the Columbia study. The GlaxoSmithKline study did have a category for the most extensive travellers -in its case, people who took more than six trips a year, and averaged greater than five days per trip. But the small sample size of only 82 people prevented results from being statistically significant. Taken together, the studies suggest people who engage in a little business travel tend to be healthier than those who don't travel at all. But the real road warriors tend to be nearly as unhealthy as the nontravellers. As the Columbia study noted: "Health outcomes were consistently worse for those not travelling and those travelling the most."

That stands to reason. Something besides health effects of travel may be skewing results when comparing light to moderate business travellers with non-travellers: Selection bias. Unhealthy people may not choose to travel; similarly, business managers may not select unhealthy people for assignments requiring travel. The healthy worker effect suggests employed individuals are healthier than non-working or non-travelling peer groups.

Something else seems to be at work with extensive travellers. Perhaps the real road warriors reflect the negative health effects of air travel. The stress of flight times and security checkpoints, family absences, job strain, jet lag, disrupted exercise routines, coupled with bad airplane air and the high-sodium and heavy-calorie meals most available to us on the road. Frequent sedentary automobile business travel has also been linked to higher BMI and obesity. Studies of World Bank travellers show that business travel can negatively affect spouses and children (particularly young children) and increase overall stress. Both Clooney's and Candy's characters were lonely without meaningful home relationships.

Over the next few months, I'll be assisting in an examination of this phenomenon of health and business travel with colleagues Dr. Kevin Kain and Dr. Michael Hawkes from the University of Toronto. Using the health records at Medcan's Travel Health Clinic, we'll analyze the health of 190 international business travellers over the course of a year with a view to making some conclusions about the way their excursions affect risk for future cardiovascular problems. Our hypothesis declares that international business travel is associated with adverse chronic health outcomes. In other words, we believe the real road warriors tend to be more like Del Griffiths than Ryan Bingham. Stay tuned for the results.