Aviation medical examinations cannot always predict is the precise moment when an apparently stable cardiovascular system becomes unstable. (File Photo)The death of an Air India first officer in Bali this week has unsettled far more than the aviation community. Here was a 40-year-old pilot, who was medically cleared pre-flight, operated within prescribed duty limits, completed an eight-hour flight, with no publicly known history of disease. He had checked into his hotel during a routine layover, complained of discomfort, had a heart attack and could not be revived despite being rushed to hospital.So how does someone pronounced fit enough to command an aircraft die of a cardiac event hours later? “The uncomfortable reality is that a heart attack comes like an earthquake, without prior notice, even in people who have every outward marker of health. An electrocardiogram (ECG) may appear normal in a resting state even when the arteries are blocked 70 per cent. So the plaque could rupture and blood would clot around it, creating a bigger block and triggering a heart attack. Besides, there could be an undiagnosed condition, a family history or other behaviour-induced risk factors like lack of sleep and stress, all of which can trigger a chain reaction,” says Dr Ranjan Shetty, lead cardiologist and medical director, Sparsh Hospital, Bengaluru. Speaking to The Indian Express, he says, “Just tame your risk factors aggressively.” Excerpts:Can long-haul flying be a trigger if the patient has other risk factors?The reduced air pressure and oxygen levels in the cabin can stress the heart, while dehydration causes blood to thicken, increasing the risk of clots. Dehydration alters electrolyte levels (potassium and sodium), which are crucial for maintaining a steady heart rhythm and may lead to irregular heart beats or arrhythmia. These electrical impulses could go awry and stop the heart suddenly, what we call sudden cardiac arrest.Long-haul flights of 8–10 hours increase the risk of deep vein thrombosis (DVT) which can lead to a pulmonary embolism (a clot traveling to the lungs). Besides, if a person already has unstable or vulnerable plaque, the physiological changes during flight can increase shear stress on vessel walls, leading to plaque rupture and subsequent heart attack.The risk of cardiovascular events, including potential ruptures, is highest 24-48 hours after arrival due to the body recovering from the stressors.Why a medical clearance is not a guarantee against sudden heart attackAviation medical examinations are designed to identify overt abnormalities — structural defects of the heart, uncontrolled hypertension, rhythm disorders or established disease serious enough to compromise operational safety. What they cannot always predict is the precise moment when an apparently stable cardiovascular system becomes unstable. Even an ECG only records about 10 seconds of electrical activity. If your heart receives adequate blood flow during those 10 seconds, the ECG will appear normal.Why are younger people getting heart attacks despite leading disciplined lives?Stress is one reason. Sometimes there is the cumulative physiological burden of sustained high-alert functioning. In professions such as aviation, the body often operates under a low but persistent elevation of stress hormones such as cortisol and adrenaline. Over time, these can promote inflammation, elevate blood pressure, and increase clotting tendency, all of which make vulnerable plaques more dangerous.Story continues below this adSleep disruption is another invisible accelerant. Even when duty rosters comply with regulations, circadian disruption exacts a biological cost. Irregular sleep triggers inflammation, destabilises blood pressure regulation and leads to wear and tear.Then there is dehydration, often underestimated in commercial flights. Reduced cabin humidity, irregular hydration patterns and post-flight fatigue can increase blood viscosity and impose additional stress on the cardiovascular system.Genetics may be the deepest hidden factor of all. A person may carry substantial inherited cardiac risk and not know about it because his parameters are within range.What about prevention?If leading a high stress life, go for calcium scoring to assess plaque deposits, continuous rhythm monitoring, and deeper family-history mapping. This will be alongside routine hypertension and blood lipid, kidney and liver function tests. Sometimes the heart offers no warning at all. It passes every test, performs every task demanded of it, and then, in the space between one ordinary hour and the next, fails. That’s why regular monitoring of markers, lifestyle correction and sleep hygiene are a must. © The Indian Express Pvt LtdTags:heart attack