Effects of flying across time zones

Frequent flying over more than three time zones can throw one’s circadian rhythm out of sync. FOTOSEARCH 

By Michael Otieno

In Summary

• Most domestic and regional flights in Africa have travellers crossing just two to three time zones, hence the physiological effects are hardly noticeable.
• Frequent flying over more than three time zones can throw one’s circadian rhythm out of sync leading people will experience sleep disturbance, memory problems and for women even irregular periods.
• Get a flight that arrives at your destination early in the evening — arrival in the afternoon or either sleeping earlier or later than usual depending on the direction of travel.

One of the most befuddling lessons in my early geography classes was learning about time zones.

As a child, it is a bit of a challenge to wrap your mind around the notion that as the sun set where you were, it was rising in another part of the world.

But as I learnt that the world has 24 time zones, it seemed normal and acceptable — that is until I took a flight across different time zones.

Most domestic and regional flights in Africa have travellers crossing just two to three time zones, hence the physiological effects are hardly noticeable.

Save for the minor time adjustments, most people notice nothing different owing to the geographical sizes and proximity of most countries on the continent.

Earlier this year, Qatar Airways launched the world’s longest direct flight from Doha to Auckland — a 14,535-kilometre flight crossing 10 time zones.

There are many other flights  over 15 hours around the world crossing numerous time zones; Doha to Los Angeles, Johannesburg to Atlanta, and Los Angeles to Singapore are just a few such long-haul direct flights. The effects of time zone changes on flyers are usually more noticeable on the longer flights and many sum it up simply as “jet lag.”

Frequent flying over more than three time zones can throw one’s circadian rhythm (24-hour cycle in the physiological processes of living beings) out of sync.

Biological changes

Given that there are certain biological changes outside our control including sunrise and sunset that our bodies go through during the day, travelling across different time zones interferes with this “normal flow” hence the disorientation most travellers feel.

According to studies done on the subject by the American National Sleep Foundation, most people notice that they naturally experience different levels of sleepiness and alertness throughout the day, because of sleep/wake homeostasis and the circadian biological clock.

The circadian rhythm causes us to feel more alert at certain points of the day, even if we have been awake for hours and our sleep/wake restorative process would otherwise make us feel sleepier.

Once the body clock is out of sync, most people will experience sleep disturbance, difficulty in concentration, indigestion, confusion, irritability, loss of appetite, memory problems and for women even irregular periods. Depending on the individual, particularly where around 10 time zones are crossed in an easterly direction, these conditions can last up to a week.

Possible effects

There are however pre-existing conditions that could lead to a stroke or heart attack in some individuals, hence it is important to be aware of your health status before such flights. The direction of the long-haul flight determines how quickly one recovers from the effects of long flights through different time zones.

For instance, travelling westwards makes it easier for people to recover from jetlag than travelling eastwards, where waking up at normal times could be difficult.

Currently, the longest direct flights out of Nairobi’s JKIA are to the Far East — a situation that will change when direct  flights to the US commence.

Remedy

What then should travellers do to minimise the effects of changing time zones on the body?

First would be to try to get a flight that arrives at your destination early in the evening — arrival in the afternoon calls for a light nap before jumping into meetings and other activities.

It is also advisable that prior to the flight, you shift your body clock to that of the destination time zone by either sleeping earlier or later than usual depending on the direction of travel.

Avoid alcohol before and during the flight as it dehydrates the body.  Consuming alcohol to “relax” the body and induce sleep and then waking up to copious amounts of coffee to stay awake once at your destination has serious heath ramifications.

ALSO READ: Plan ahead to reduce stress when flying

Exposure to natural light, particularly in the early morning, helps to get the body’s circadian rhythm back on track.

For flyers who do not have time to allow the body to adjust before having to change time zones again, it is important to work with a professional or doctor to manage the effects travel is having on the body.  

Michael Otieno is an aviation consultant based in Nairobi. Twitter: @pmykee143, Email: michael@sadimsolutions.com.