Common questions

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by Professor Colin Espie

Is it worth trying to adjust the body clock if I'm only away for a few days?

It depends on what your plans are while you're away. If you're only one or two time zones from home, you might manage maintain your usual schedule, provided that you arrange important meetings at times you're usually alert.

Does everyone suffer from jet lag?

The risk and severity of jet lag increase with the number of time zones you cross. More than three hours of time difference are usually required to trigger a problem. Older adults often experience worse symptoms than younger adults. Young children have less developed daily rhythms; babies under the age of 3 don't seem to be affected by jet lag at all.

Is it worse flying east or west?

Travelling eastward typically causes worse disruption than travelling in a westward direction. This is because most people find it harder to shorten than to lengthen their natural daily cycle.

Should I take melatonin?

Melatonin is a natural hormone that helps to get the body ready for sleep. It is produced by the brain's pineal gland in response to darkness. In the US, synthetic melatonin is sold as a nutritional supplement and advertised to help regulate sleep-wake cycles.

In a recent review of jet lag trials, most studies found that melatonin was more helpful than a placebo for reducing self-reported sleepiness, but the effects were modest (Costello et al 2014). There were no serious side effects from short term use, but one trial did note an increase in morning sleepiness.

In the EU, it is classified as a medicinal product, and is only legally available on prescription from a doctor. Similarly melatonin is not available over the counter in Australia, Greece, New Zealand, Brazil, South Africa, Iceland.

Should I take sleeping pills?

Sleeping pills, or hypnotics, can help some people get to sleep, and to stay asleep, but they won't help the other aspects of jet lag (aligning the body clock to the new timezone). Hypnotics are also associated with side effects, including headache, dizziness, nausea, confusion, and amnesia, which may outweigh any short-term benefits.

Next: The science of jet lag

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