We all “feel” different when we travel frequently for business, but did you know that frequent business travel, shift work and fly-in-fly-out [FIIFO] travel can start to make you “fat” in as little as 3 weeks? If you travel regularly for business, or manage frequent business travellers, then you need to read this article. By the end of the article, you will understand the hazard, and the form beginning of a plan to manage this travel health and safety risk.

Dr Orfeu Buxton, an assistant professor in the division of sleep medicine at Harvard Medical School, and his colleagues, found that over a 5 week intensive study, that the resting metabolic rate of test subjects was 8% lower than before the sleep/wake disruption experimentation. After three weeks in the lab, the participants produced about a third less insulin from the pancreas in response to meals; with less insulin available to break down glucose, blood glucose levels started to rise and three of the 21 volunteers showed high enough levels to qualify them as pre-diabetic.

“If you’re not getting enough sleep, then it’s hard to find the energy to exercise,” says Buxton. “And if you’re not getting enough sleep, you not only eat more than you need but you tend to make poorer food choices. So in terms of obtaining optimum health, all three pillars — diet, exercise and sleep — are important.” Source

 Pilots Suffer From it Too

The Federal Aviation Administration in the US advises pilots on the hazard, with detailed instructions on prevention and management of the issues associated with frequent business travel, shift work and time zone changes.


The issue was reported as early as Charles Lindbergh TransAtlantic crossing. Source

Circadian Rhythm Sleep Disorders

What is it?

Circadian rhythm disorders are disruptions in a person’s circadian rhythm — a name given to the “internal body clock” that regulates the (approximately) 24-hour cycle of biological processes. The term circadian comes from Latin words that literally mean around the day. There are patterns of brain wave activity, hormone production, cell regeneration, and other biological activities linked to this 24-hour cycle.

The circadian rhythm is important in determining sleeping patterns such as when we sleep and when we wake, every 24 hours.The normal circadian clock is set by the light-dark cycle over 24 hours. Source

The circadian rhythm sleep disorder, jet lag type (or jet lag disorder) occurs when there is a temporary mismatch between sleep-wake cycle timing generated by the endogenous circadian clock and the sleep-wake pattern required by a time-zone change. In general, eastward travel causes more severe jet lag than westward travel because the biological clock adjusts better to a longer than a shorter day. However, the ability and speed to adapt varies with the individual. Source

Common Circadian Rhythm Disorders

  • Jet Lag or Rapid Time Zone Change Syndrome: This syndrome consists of symptoms that include excessive sleepiness and a lack of daytime alertness in people who travel across time zones.
  • Shift Work Sleep Disorder: This sleep disorder affects people who frequently rotate shifts or work at night.
  • Delayed Sleep Phase Syndrome (DSPS): This is a disorder of sleep timing. People with DSPS tend to fall asleep very late at night and have difficulty waking up in time for work, school, or social engagements.
  • Advanced Sleep Phase Syndrome (ASPD): This is a disorder in which a person goes to sleep earlier and wakes earlier than desired. ASPD results in symptoms of evening sleepiness, going to bed earlier (for example, between 6 p.m. and 9 p.m.), and waking up earlier than desired (for example, between 1 a.m. and 5 a.m.)
  • Non 24-Hour Sleep Wake Disorder:  This disorder frequently affects those that are totally blind since the circadian clock is set by light-dark cycle over a 24 hour period. In non-24 hour sleep wake disorder the cycle is disturbed. The disorder result in drastically reduced sleep time and sleep quality at night and problems with sleepiness during daylight hours.Source


Typical consequences of jet lag are disturbed sleep, decreased alertness, and impaired daytime function, in addition to gastrointestinal distress and general malaise. Source

Who is Affected?

Jet lag can affect all age groups. However, the elderly may have more severe symptoms and require a longer recovery time. Source

Jet Lag Treatment Suggestions

  • Proper sleep hygiene (i.e. avoiding caffeine, optimizing the sleeping environment) is important in helping to reduce the effects of jet lag.
  • Carefully timed bright light therapy can be effective. In one 3-day study, 3.5 hours of morning bright light therapy, either continuous (>3000 lux), or intermittent (>3000 lux, 30 minutes on, 30 minutes off), or 3.5 hours of morning dim indoor light (<60 lux) were effective in advancing circadian rhythms prior to eastward travel.2 In a separate 3-day study, 3.5 hours of intermittent morning bright light (5,000 lux for 30 minutes alternating with <60 lux for 30 minutes), combined with a gradually advancing sleep schedule (1 or 2 hours per day), was also effective in advancing circadian rhythms prior to eastbound travel. Source

The findings highlight how important the sleep-wake cycle can be for metabolism and health. “It’s harder to dismiss the [observational] studies and workplace studies that show night work is a health risk,” he says. “We’ve shown unhealthy mechanisms can occur even in healthy subjects, so the time for dismissing night work as a health risk is well past.” Source

Now you know it just isn’t a ‘feeling” when you travel or disrupt your sleep. Your body is actually conspiring against you by reducing your ability to process foods, store fat and increase your risk of diabetes. Frequent business travel, shift work, fly-in-fly-out or other similar activities that disrupt your sleeping and rest rhythms, can start to make you fat in as little as 3 weeks. Know this, understand this and work to maximise your rest, sleep and those you manage to ensure this hazard doesn’t escalate to a level of concern or compound existing health conditions in your business travellers.

Travel Safety Experts
Travel Safety Experts

Travel health, safety, security and risk management experts