Jet lag and the solution

Jet lag, also known as circadian dysynchronism or flight dysrhythmia, is a temporary condition that arises as a result of rapid air travel across multiple time zones. It is characterised by symptoms such as disturbed sleep patterns, fatigue, insomnia and irritability, which develop because of the body’s inability to adapt to the new time zone.

Causes of jet lag

Jet lag occurs when there is a disturbance in the synchronisation that exists between the body’s internal clock (circadian rhythm) and the external environmental rhythms. The internal body clock has a natural 24-hour routine that works in sync with environmental cues (also known as zeitgebers, or ‘time givers’) such as daylight to control the sleep-wake cycle. When travelling across time zones, the natural rhythms of the body that are synchronised with the day-night cycles of the environment cannot adjust instantly. As a result, the brain may trigger activities that the body may not be prepared for, leading to the symptoms of jet lag.

Melatonin is a hormone produced by the pineal gland in the hypothalamus of the brain. Melatonin plays a key role in jet lag and in mediating body rhythms. The internal body clock is a localised group of cells, located in the hypothalamus, which has receptors to melatonin. Melatonin is released in response to darkness and promotes sleep. Daylight inhibits melatonin secretion, thereby encouraging daytime activity.

Travellers flying east experience the most problems and require the longest time to adapt, compared to those flying west. It is easier for the body to readjust when travelling west because of the gain in time, rather than travelling east when time is lost. Travelling eastward can result in difficulties falling asleep and rising in the morning, while westward travel is associated with early evening sleepiness and premature awakening.

Flying north or south usually does not cause jet lag, as you are flying within the same time zone.

Who gets jet lag?

Not everyone experiences jet lag and individual experiences can vary widely. Additionally, the intensity of jet lag experienced varies with the number of time zones crossed and the direction of travel. Most people feel the effects of jet lag after crossing at least three time zones. Those aged over 50 are most vulnerable.

Symptoms of jet lag

Symptoms include: Insomnia, fatigue, nausea, headache, irritability, poor concentration, clumsiness, difficulty with memory, general weakness, difficulty sleeping and maintaining sleep at night, gastrointestinal disturbances (e.g. diarrhoea, constipation, indigestion, loss of appetite)

Also, irregular menstrual cycles are frequently reported by women.

Jet lag can be disruptive for business travellers and holiday-makers. It can also affect performance and jeopardise training in athletes. 

Management of jet lag

There is currently no available treatment but some behavioural strategies which can help to prevent and/or minimise the severity of jet lag:

Avoid eating large meals;

Drink plenty of water;

Limit caffeine and alcohol consumption during flight;

Get plenty of rest in the days prior to departure;

Break up the journey with a stopover;

If you have a meeting or conference, plan to arrive a few days early;

If it is night time at the destination, try to sleep on the plane;

For an eastbound flight, try to sleep an hour earlier than normal a few days before leaving;

If you are flying west, try to sleep later than usual;

Optimise exposure to available sunlight following arrival at your destination;

Eat small meals at the correct times at your destination;

Exercise lightly during daylight at your destination.

Light treatment

If you are travelling westward, it is best to stay awake during daylight at the destination and sleep when it gets dark. Following an eastward flight, avoid bright light in the morning and spend as much time as possible outdoors in the afternoon. The more time spent outdoors in the first few days following travel, the faster the adjustment to the new time zone. 

Melatonin supplements

The effectiveness of melatonin supplements in alleviating the symptoms of jet lag is currently inconclusive. Oral melatonin advances the body clock and increases sleepiness if taken in the evening, and delays the body clock if given in the morning. It is suggested that melatonin (2-5 mg) should be taken at bedtime, beginning 3-4 days before departure and continued for 2-4 days after arrival.

Promotion of alertness

Caffeine is the only substance recommended for maintaining daytime alertness. Naps also have an important role, as they top up sleep and can help improve alertness and performance.

Promotion of sleep

While there is no way to avoid jet lag, there are ways to overcome it faster by making sure you stay awake until 10 pm local time on the day you arrive in order for your body to adjust. If you do need to sleep before, then make sure it is only a very quick nap, not longer than 2 hours.

Diet

Another possible treatment strategy that may be beneficial is to follow the Argonne diet. The Argonne diet involves alternating days of feasting on high protein breakfasts and lunches and high carbohydrate dinners, with days of fasting with small low-calorie meals.

The theory behind this is that high protein meals increase levels of epinephrine and dopamine in the body, promoting alertness, whereas high carbohydrate meals increase serotonin and melatonin, and prepare the body for sleep. Alternate day feeding apparently reduces the impact of the rapid time shift on the internal clock.

The diet begins with a feast on the fourth day before departure and is followed by alternate days of fasting and feeding

So, don’t be afraid of jet lag and enjoy your air travel with the help of this article.