People + Process = Performance

Two Troubling Studies on the Effect of Obesity and Driving: Part 1

It is well known that obesity is an epidemic in America with over 60% of Americans either overweight or obese. (1) Recently there have been two studies published which caught my attention due to fact that both were in regards to obesity and driving.  Both studies left me to believe that ergonomics and wellness are imperative for employers as well as communities.  Let me explain why.

The first study (2) examined truck drivers—those normal weight and those obese.  Unfortunately, the study showed that obese truckers are more likely than their normal-weight peers to get into an accident in their first two years on the job.

It isn’t surprising to see truck drivers to carry a few extra pounds around the middle.  After all they spend long hours sitting in the truck cab and often in stressful conditions.  Trucking isn’t exactly the conducive to good health.  Studies have shown that truck drivers in general don’t get enough sleep and they are more likely than the general population to smoke, be overweight and suffer from sleep disorders.  Persons who are overweight or obese are at greater risk for sleep apnea.  As we all know, fatigue and driving are a dangerous mix.  In this case, the risk defined itself in terms of more crashes.

The study was led by Stephen Burks, a former truck driver and behavioral economist at University of MN, Morris.  Burks has been working with Schneider National, a national truck driving company, to identify factors that affect truck driver health and safety.  This study looked at Schneider National’s new drivers over a period of two years.  The researchers looked at those drivers’ BMI (height and weight calculation) and compared that to every accident they had during that time period.  The evidence was very clear in that it showed the highest BMI drivers were at higher risk of having an accident.

During their first 2 years on the road, drivers with a BMI higher than 35 (“severely obese”) were 43% to 55% more likely to crash than were drivers with a normal BMI. Drivers who were overweight or obese, but not severely, did not appear to be at higher risk, and the study does not indicate why. The relationship held even when the researchers corrected for number of miles on the road, geographic location, age, and other crash risk factors.

The authors suggest the increased risk may be due to sleep apnea, a sleep disorder strongly associated with obesity that can cause potentially dangerous daytime drowsiness.  Other factors were suggested as well including limited agility or fatigue that’s associated with obesity but not due to sleep apnea

Based upon this study’s findings, it should be clear that it would benefit truck driving companies and drivers alike to determine ways to increase the driver’s health and wellness.  In addition, research needs to be done to determine if there are any engineering controls that would negate the effects of obesity on driving, especially related to fatigue.

It would be interesting to know if other industries experience more accidents or errors from obese employees.  If so, the need to design the work to reduce the risks, i.e. ergonomics, and increase employee participation in wellness programs to reduce/normalize weight is imperative to the health and wellness of both the employee and the employer

In part 2 we’ll look at another study (3) that looked at persons involved in car accidents and the rate of survival among obese and non-obese.

  1. http://www.cdc.gov/nchs/fastats/overwt.htm
  2. Obesity is associated with the future risk of heavy truck crashes among newly recruited commercial drivers http://www.sciencedirect.com/science/article/pii/S000145751200084X
  3. Driver obesity and the risk of fatal injury during traffic collisions http://emj.bmj.com/content/early/2013/01/25/emermed-2012-201859