What does flying do to your body? Top cardiologist shares how to protect your heart on a flight

Entering an aircraft for a flight can feel like a seamless leap from the solid ground beneath your feet to the vastness of the skies above, particularly for those who are accustomed to flying regularly. As you step aboard the plane, you find your seat and make yourself comfortable, possibly feeling that the real journey begins only after you get settled. Aside from a few fleeting moments of apprehension during the crucial phases of takeoff and landing, the entire experience appears to be an effortless glide — or more accurately, a leisurely soar through the clouds!


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Your mind is aligned and sorted — but what about your body?

According to a well-known cardiologist, Dr. Dmitry Yaranov, who goes by the name “heart_transplant_doc” on Instagram, flying is far more taxing on your body, especially your heart, than most people realise. As per Dr. Yaranov, what seems like a relaxed reclined seat at 35,000 feet is in fact a landscape of reduced oxygen pressure, drier air, thicker blood, and limited movement — all of which place extra strain on your cardiovascular system.

Intrigued? Read on to know more what Dr Yaranov says...

Heart on a flight: What really happens

From reduced cabin pressure and dry air to prolonged immobility and subtle oxygen drops, the conditions inside an aircraft cabin place extra strain on your cardiovascular system, Dr. Yaranov explained via a video shared on his Instagram page. As per the heart_transplat_doc, “most people think flying is just sitting in a chair in the sky. But your body, especially your heart, is doing real work up there.”

What happens to the heart?

Dr. Yaranov wrote on his Instagram post,

“What happens during a flight:

• Cabin pressure drops → oxygen levels fall

• Heart works harder to deliver the same oxygen

• Cabin air is drier than the desert → you lose water just by breathing

• Blood volume goes down → blood gets a little thicker

• Sitting still slows circulation → legs get heavy + swollen

• Airway lining dries → immune system barrier weakens

• That “jet lag” feeling?

Not just time zones.

It’s physiology.”


But what does that mean?

Here’s a breakdown of key physiological changes and why they matter:

Pressure and oxygen changes: Aircraft cabins are pressurised, but still simulate altitudes of about 6,000 – 8,000 feet. The result: slightly lower oxygen levels in your blood. Your heart must pump harder and faster to deliver sufficient oxygen to tissues. When oxygen drops, heart rate and cardiac output increase to compensate.

Dry air and dehydration: Cabin humidity is extremely low. Breathing in this dry air causes water loss from your body, which can thicken blood slightly and increase circulatory strain. Dehydrated blood circulates with more difficulty, making the heart’s job tougher.

Prolonged immobility and circulation issues: Staying seated for long periods, especially during long-haul flights, reduces leg movement, slows circulation, and increases the risk of blood pooling in the lower limbs. This can raise the risk of deep vein thrombosis (DVT) or even clots that travel to the lungs or heart.

Stress, blood pressure, and heart rhythm: Travel often comes with stress, anxiety, changes in sleep and disrupted routines, which can all elevate heart rate and blood pressure. Combined with the above factors, your cardiovascular system faces multiple small shocks.

Who is at greater risk?

For many healthy travellers, flying is well tolerated. But certain groups need to take extra care. For example, people with a recent heart attack, heart surgery, or unstable angina, those with heart failure, valvular disease, arrhythmia, or pulmonary hypertension must be more cautious. Besides, passengers on long-haul flights who remain immobile for hours should pay attention as well.

How to protect your heart on a flight?

Dr Yaranov provides the solution as well, writing:

“What I do to protect myself (every flight):

• Hydrate before boarding (start ahead, not behind)

• Skip salt + alcohol in the air (both thicken blood)

• Stand / stretch every hour to keep circulation moving

• Use saline nasal spray before takeoff to protect immune defense

• Walk after landing to reset blood flow + oxygen delivery”

What can you do?

• Hydrate well before and during the flight: Begin drinking water before boarding. Avoid excessive alcohol or caffeine, as they dehydrate and thicken blood.
• Stand up, walk, and stretch every hour: Even simple leg and ankle movements matter, especially on a long flight. Try taking a short walk down the aisle to boost circulation.
• Avoid excess salt and alcohol in flight: These only increase blood volume shifts and dehydration, adding circulatory burden.
• Wear compression socks if recommended: For longer flights, especially for those with DVT risk, compression stockings can help leg circulation.
• Inform the airline and pack medication: If you have a heart condition, consult your cardiologist before flying, travel with your records, and keep essential meds in your carry-on.