Why we may fall ill when we’re on holiday

By Claudia Hammond, Features correspondent
(Getty Images)
(Getty Images)

Does rushing to meet work deadlines before a break leave you more prone to coming down with an illness? Claudia Hammond finds out.

I’ve lost count of the number of people who have told me how they rushed to get everything done in the run-up to their holiday, only to be struck down with a stinking cold the moment they stopped work. It doesn’t need to be during wintertime: summer holidays, beach trips and short breaks can all fall foul of a post-work health slump too.

There’s even a name for this affliction – leisure sickness. Ad Vingerhoets, the Dutch psychologist who came up with the name, concedes this diagnosis is not yet established in the medical literature; nevertheless, the idea that you fall ill as soon as you stop work is one which many will recognise from bitter experience. So, how valid is it really?

(Getty Images)
(Getty Images)

There’s been no large systematic study to find out whether people are more likely to fall ill when on holiday than during everyday life. But to try to put some figures on it, Vingerhoets asked more than 1,800 people whether they thought they suffered from leisure sickness. Just over 3% of people said they did. Considering how likely we are to feel stressed and work extra-hard before a holiday, this suggests it’s not the norm and even quite unusual – especially because this study relied on asking people to judge for themselves whether it happened, and we’re more likely to remember a holiday ruined by an illness, than all the ones unblemished by a cold. We don’t remark on it when we go on holiday and feel fine.  

But if a small percentage of people are convinced they experience this, is there a physiological explanation? Almost half the people in Vingerhoets’ study put it down to the transition from work to holiday. There are several theories why this might be the case.

Sick list

The first goes that when we finally get the chance to relax, the stress hormones that help us cope with work deadlines get out of balance, and leave us open to infection. Adrenaline helps us to cope with stress, as well as boosting the immune system to help fight infections and keep us well. Along with it comes cortisol which also helps with the stress, but at a cost to the immune system. It all sounds plausible, particularly if the transition from stress to relaxation is fast, but not enough research has been done yet to confirm whether this hypothesis holds true.

There again, perhaps people are ill all along. They are so busy and determined to battle on until their holiday arrives that they simply don’t notice they are becoming ill until they have the chance to relax on holiday.

It’s certainly the case that how we rate our symptoms depends on what else we’re doing. The psychologist James Pennebaker found that the less that’s going on around a person, the worse they say their symptoms are.

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(Getty Images)

He had a set of students rate every 30 seconds of a film to say how interesting it was. Then he showed the same film to another group of students and monitored how often they coughed. The more interesting the scene in the film, the less they coughed. In the boring bits they seemed to notice their sore throats and cough a lot… observations that might interest any concert performers fed up with audiences coughing. That said, while you may notice aches and pains more when you are free from the workplace, you’re probably going to notice a thick head and a runny nose however hard you’re working.

Cabin fever

An entirely different possibility is that it’s not the stress of work that’s making us ill, but the holiday itself. Travelling is always tiring, particularly by plane, and the longer the flight the more likely you are to pick up a virus. The average American gets 2.5 colds a year, and on this basis researchers calculated the chances of catching a cold on a single flight should be 1% for an adult. But when patients were surveyed a week after flying from San Francisco Bay to Denver, 20% of them had developed a cold. If this infection rate held all year round, you’d expect to get more than 56 colds a year, in other words be prone to the sniffles every week.

(Getty Images)
(Getty Images)

Recycling air in planes is often blamed for this rate of infection, but in this study it made no difference. The researchers blamed two other culprits: sitting in an enclosed space, closer to other people’s germs than you normally would be; and humidity. They hypothesise that the dry air in planes could cause the virus and bacteria-trapping mucus in our noses to become too thick for the fine hairs to pass it down the throat to our stomachs for destruction.

Vingerhoets is open to other explanations for people getting ill on holiday. There’s even a suggestion that if you don’t really like a holiday, being ill gets you out of it. But the lack of research in this area makes it impossible to pick out one explanation from the others, and it could even be a combination of these factors.

The good news, though, is that it’s rarer than you might expect. Even better, as we get older our immune systems have had more time to develop antibodies ,and we get fewer and fewer colds, whether we’re on holiday or not. Finally, that’s one aspect of getting older to look forward to.

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