I don't remember much of the first week of my honeymoon. I was curled up in bed in a hotel in Antigua, feeling nauseous, aching from head to foot, unable to venture further than the luxury bathroom.
The complimentary champagne remained unopened; the super-bouncy kingsize honeymoon four-poster no more than a luxurious sickbed. I thought I was suffering from exhaustion. It now seems I may have been suffering from something called leisure sickness.
Leisure sickness, like paradise syndrome, chronic fatigue syndrome, seasonal affective disorder and sick building syndrome, is one of those modern conditions that sounds bogus, the pointless invention of some under-employed researcher, unless you happen to suffer from it, that is.
How do you know if you have been struck down with leisure sickness? Well, think back to the past few times you were ill. Did you have to take time off work? Or, after a prolonged period of good health, were you struck down by some mystery bug just as you were setting off on a long-awaited two-week vacation to some far-flung corner of the world? If it is the latter, chances are you, too, have leisure sickness.
This is a typical story. "Once I went on a holiday I had been really looking forward to - in Africa. It was a walking holiday which meant I had to be quite robust. I was brilliantly well, really looking forward to it, then as soon as I was on the plane I went down with severe flu-like symptoms.
"By the time I got there I could hardly swallow and I was ill for the next 13 days. It wasn't until I was on the way back that I started to feel better."
The condition has been identified by Dutch psychologist Professor Ad Vingerhoets, of Tilburg University, who started researching the subject after he became curious about his own pattern of illness. "If I am ill then it's at the weekend or at Christmas. Then I heard stories from friends who all said the same thing, and I thought, what the hell is going on? I tried to find some literature on it, but I couldn't find anything, so I decided to do a first study."
Vingerhoets, who surveyed 1,128 men and 765 women across Holland between the ages of 16 and 87, estimates that around 3% of the population may suffer from weekend or vacation sickness. In a further in-depth study of 114 Dutch sufferers, he found that the most frequently reported symptoms included headaches, migraine, fatigue, muscular pains, nausea and, particularly in relation to vacation, viral infections causing flu-like symptoms and colds.
Most of those affected had been suffering from leisure sickness for over 10 years and associated the onset of the illness with a major life event, such as marriage, birth of a first child or a change of job. Many of those affected shared certain characteristics - a high workload, perfectionism, eagerness to achieve and an over-developed sense of responsibility to their work, making it difficult for them to switch off out of work.
According to Vingerhoets, there are a number of possible explanations for the condition. "One possibility is a kind of competition for symptom perception. There is a competition between information from the outside world, external information, and information from the body, internal information.
"If you are very busy with external information, then information from your body might be repressed by it. If you are in a boring environment, it is more easy to recognise those signals from your body. When you are in a stimulating environment, you don't attend to those signals."
It also raises the possibility of mind over matter - that individuals have the power to postpone illness to a more appropriate time when it won't interfere with work commitments. "It's more or less similar to what's already well known among people with terminal illnesses," says Vingerhoets. "They can delay their death to allow them to see events which are important to them, like the birth of a grandson, or a marriage."
Another possible explanation is that, contrary to popular belief, when the body is under acute stress, it has greater rather than lower resistance to disease.
Psychologist and psychotherapist Leila Collins, who is principal lecturer at Middlesex University, is all too familiar with the condition. "I suffer from it myself. When I go away on holidays, for the first week or so, I'm good for nothing. I've been sick all over the globe. I used to get sick all the time.
"While you are at work your body is in a state of defence. Your body responses are sharper. You are concentrating, you are focused and your body's defence mechanism is working efficiently. The minute you go off duty, you relax and let go, and those defences become a bit more relaxed. And then you catch whatever is going. Headaches come back, sickness, colds and flu.
"I know many colleagues who spend most of their annual leave being sick. They go abroad and get sick. I don't think it's a modern phenomenon. It has always existed, but we haven't taken any notice of it before. We are a nation of workaholics. We all look forward so much to our weekends, but the number of people who spend their weekends in bed is quite amazing."
So what do you do if you want to avoid leisure sickness? Of the 20 people in the Dutch study who claimed to have recovered from the condition, 85% were able to identify a specific life change or episode they held responsible for its disappearance, either a change of job or a fundamental change in attitude towards work and life in general.
But if you can't change your job (or your attitude), Vingerhoets suggests exercise on a Friday evening, which can help with the transition from work to weekend leisure; or if you are a perfectionist who takes work responsibilities too seriously, see a psychologist for some cognitive therapy.
Alternatively, stick to work and forget the holidays. It's cheaper, and they only make you sick.