Think twice before booking your next foreign holiday, especially if you have heart or lung disease

“The whole world is in a terrible state o’ chassis,” Sean O’Casey wrote in Juno and the Paycock. From our current environmental and meteorological perspectives, never a truer word was spoken.

This was brought home to me quite vividly during a recent trip to Canada to visit family. We were enjoying typical weather for southern Ontario at this time of year, with warm days pleasantly leavened by an occasional zephyr from Lake Ontario. Then, one morning, everything changed.

I had been aware of wildfire activity across all provinces of Canada this summer. The nearest to us was in northern Ontario and parts of Quebec. But when the wind changed to a northerly direction, we woke up to a thick smoke-filled environment. Amid public health warnings and advisories, we experienced four days of continuous poor air quality.

A combination of very dry air from Africa and extremely high temperatures across southern Europe means that the risk of wildfires has skyrocketed

People stayed indoors as much as possible. I don’t have respiratory issues, but on the fourth and worst day of poor air quality, the air I was breathing in was similar to inhaling burnt newspaper: cough and gag-inducing and most unpleasant.

An Irishwoman in Denmark: ‘Life here is good, safe. But a bit boring if I am honest’

---

Coleen Nolan: ‘I haven’t had two failed marriages, I’ve had two amazing marriages, because they gave me amazing children’

---

Rod Stewart in Dublin review: The 79-year-old rock icon does his best to keep misery at bay amid downpours

---

‘My main takeaways a year after swapping Ireland for Portugal’

---

Anyone suffering with chronic bronchitis and asthma would be in trouble in this wildfire-induced smoky environment. Wildfires release fine particulate matter known as PM2.5, which is made up of tiny particles 2.5 microns in diameter or less (that’s roughly 30 times smaller than the diameter of a human hair). These particles can enter the lungs and bloodstream, and are particularly harmful for those with pre-existing conditions.

While forested areas make up a lower percentage of the landmass in Europe, we are not immune to wildfires. As I write, evacuation orders are in place on the Canary Island of La Palma as a wildfire continues to burn out of control. A combination of very dry air from Africa and extremely high temperatures across southern Europe means that the risk of wildfires has skyrocketed.

People in urban areas won’t escape the environmental challenge. It is estimated that more than 90 per cent of Europeans living in cities are exposed to harmful levels of fine particulate matter, leading to more than 200,000 premature deaths per year in Europe.

[ Pollution from Canadian wildfires continues to spread ]

Meanwhile, if you have been diagnosed with heart disease, you need to be careful as temperatures rise. Recent research published in the Journal of Applied Physiology shows that even young people can experience cardiac side-effects when under progressive heat stress. Significantly, a rise in heart rate, known as cardiovascular strain, occurs even before a person’s internal temperature starts to increase.

A major review, published last year in The Lancet Planetary Health, strengthens evidence of increased cardiac health risks related to heat exposures, and provides new evidence that these risks vary geographically and are dependent on underlying climate conditions. It shows that for every one degree increase in temperature above reference temperatures there is an associated 2.1 per cent increase in deaths from cardiovascular disease. Stronger risks were shown with stroke (3.8 per cent increased risk) and coronary heart diseases (2.8 per cent increased risk). In addition, during heatwaves, the risk of cardiovascular disease-related mortality significantly increased by 11.7 per cent, with the risk increasing as heatwave intensity increased.

If you have been diagnosed with heart disease, you need to be careful as temperatures rise

Older people are especially at risk: they have low tolerance to heat and their cardiovascular capacity declines with age. This means that during heat exposure, older individuals generally respond with reduced sweat production, reduced blood flow to the skin, and smaller increases in cardiac output. People aged 65 years and older tend to have a higher rate of pre-existing conditions – such as hypertension, diabetes mellitus and coronary artery disease – which help to explain poor cardiac disease outcomes in response to heat.

So, for those with asthma, chronic obstructive pulmonary disease, ischaemic heart disease, diabetes or experience of a previous stroke or heart attack, the take-home health message is clear: you need to factor in extremes of heat and the risk of wildfires when planning your next foreign holiday.

mhouston@irishtimes.com