Medical Matters:There was a good response to last week's request for "cures" for jet lag. A regular traveller to New Zealand says he goes for a run as soon as he arrives and continues to exercise every day while abroad.
He reckons it helps him function reasonably well within 24 hours of getting to the other side of the world.
For those who detest the dysfunctional feeling associated with arriving back in Ireland from the US at five or six in the morning, a reader offers what she says is a fail-safe remedy: have tea and toast; go to bed for two hours; get up then, no matter how tired you feel; work through the day and go to bed that evening at your normal time. "Next day I am fine," she says.
Another correspondent recommends a "magic potion". An Australian bush flower remedy called Travel Essence, taken while travelling and after arrival for three days, means the reader is able to sleep normally. "Although there is no scientific proof to show how this works, I would not let that put anyone off," she declares.
In keeping with the theme of travel medicine, this week I will look at a variety of health issues that may restrict air travel. The extraordinary saga of Andrew Speaker, an American with newly diagnosed tuberculosis (TB) who flew to Europe recently for his wedding and honeymoon, is a reminder that there are times when it is best not to fly. Despite being told he could infect other passengers on a long flight, the lawyer flew to France, Greece, Italy, the Czech Republic and Canada in defiance of a quarantine order.
Although rare, there have been reports of TB being transmitted to fellow passengers by an air traveller with an actively infectious form of the disease. As a general rule, people with respiratory or cardiac disease with pronounced breathlessness at rest probably should not travel by air. This is because the cabin air pressure drops as the plane ascends to a pressure equivalent to that found on top of an 8,000ft mountain.
The consequent decrease in the amount of oxygen carried by the blood, while not an issue for healthy travellers, can trigger medical problems in those with unstable angina, severe heart failure or severe respiratory disease.
In flight, the volume of air also expands by 30 per cent posing a potential problem for passengers who have had recent surgery. With the growth of "health travel" by those seeking medical treatment abroad, flying within five to 10 days of an operation could result in the re-opening of wounds and other problems.
Other contraindications to flying commercially include having a stroke within two weeks of travelling, an uncomplicated heart attack in the previous two-three weeks and within 10-14 days of a cardiac bypass.
Pregnant women can travel by air up to the end of 36 weeks' gestation, although if expecting twins or triplets, it is recommended they stay grounded after 34 weeks. Many airlines will request a medical certificate after 28 weeks to confirm that there are no pregnancy complications. Leaving air travel to seven days after the birth is best for both mother and baby.
There is generally no evidence that commercial air travel is hazardous in pregnancy. The additional radiation exposure to a foetus on a single flight is minimal and is most unlikely to have any adverse effects.
Severe air turbulence could, in theory, put the baby at risk, with a recent report of a case where the placenta separated following a seat belt injury during extreme turbulence. Pregnant travellers should wear a seat belt at all times when seated and fasten it low around the pelvis to avoid trauma to the baby. The expansion of intestinal gas at altitude can cause discomfort in late pregnancy; avoiding gas-producing foods in the days before the flight may help.
Pregnancy is of course a risk factor for developing a clot in the leg (a deep vein thrombosis - DVT). Along with a family history of DVT and a recent heart attack, pregnancy poses a moderate risk of thrombosis.
To minimise the risk, ask for an aisle seat, exercise both in the seat and with short walks around the cabin and consider wearing graduated elastic compression stockings. While the true incidence of travel-related thrombosis is unknown, it is estimated to occur in 2-4 per cent of passengers.
But the good news is that the majority of these are asymptomatic, with only a small fraction developing a full-blown DVT or clot that travels to the lung (pulmonary embolus).
Travelling distances over 5,000km is associated with the greatest risk of DVT. And those with a previous personal history of thrombosis, a previous stroke, a current cancer and a patient within six weeks of major surgery are classified as high risk for a DVT.
For people at high risk, there is some evidence that injecting a low molecular weight heparin an anti-coagulant) two-four hours before travel helps reduce the prevalence of thrombosis. But the decision about using this is made on a case-by-case basis. As with all medical aspects of air travel, it is best discussed in detail with your doctor.
Again, I wish to acknowledge the assistance of Dr Francis Nelson, GP continuing medical education tutor in resourcing this column.
Dr Muiris Houston is pleased to hear from readers at mhouston@irish-times.ie but regrets he is unable to reply to individual medical queries.
