June 17, 2024 – Do you will have an extended flight coming up in your near future? Before you board, it is advisable to re-evaluate about whether to order that drink, Relax or go to sleepP.
As airplanes climb to cruising altitudes (30,000 to 40,000 feet), the pressure within the atmosphere drops, affecting the power of oxygen to pass from the lungs into the blood. (This is named the arterial partial pressure of oxygen.) This, in turn, affects how well the lungs move oxygen from the air into the blood whenever you breathe in and take away carbon dioxide whenever you breathe out, in addition to how much oxygen circulates within the blood.
For most individuals, a Blood oxygen levelor saturation, is taken into account healthy. Commercial flights must maintain a minimum cabin pressure that maintains a healthy blood saturation of 90%.
However, scientists warn that a mixture of altitude, cabin pressure, alcohol and sleep on long-haul flights (over six hours) might be problematic for adults, especially those with risk aspects for certain diseases or heart and lung conditions.
In a new studyThe researchers assigned 48 healthy individuals between the ages of 18 and 40 to either 1) a sleep laboratory under normal sea level pressure conditions or 2) an altitude chamber that simulated cabin pressure at cruising altitude.
Twelve people in each setting slept for 4 hours without consuming any alcohol, while 12 others slept for 4 hours after consuming enough alcohol to succeed in a blood alcohol content of 0.06% (the same old limit for driving within the US is 0.08%) in a single night. This was followed by a 2-day recovery period after which one other night in each group, but in reverse order of alcohol consumption.
“After moderate alcohol consumption, oxygen saturation during sleep dropped below 90% and remained there for some time – 201 out of 240 minutes,” said Dr. Eva-Maria Elmenhorst, physiologist, co-author of the study and deputy head of the Department of Sleep and Human Factor Research on the Institute of Aerospace Medicine in Cologne. This phenomenon is named “hypobaric Hypoxia”, also known as low blood oxygen at higher altitudes.
In addition, the heart rate of the study participants did not decrease as usual during sleep, but increased to an average of 88 beats per minute, she said.
“We are concerned that individuals with pre-existing medical conditions could board an aircraft with an already low oxygen saturation that drops even further during sleep after consuming alcohol, which could worsen their condition and result in a medical emergency throughout the flight,” said Elmenhorst.
About Hypoxia
“When we discuss hypoxia, we essentially mean a discount in the quantity of oxygen available so that you can breathe,” said William Kent Cornwell III, MD, director of sports cardiology and associate professor of medicine at the University of Colorado Hospital in Denver.
He said hypoxia can be caused by the environment or atmosphere (as occurs in airplanes) or by an internal reaction to the amount of oxygen available due to medical circumstances. The body's response is to increase the amount of fight-or-flight hormones.
“The worse the hypoxia or the higher the altitude you are at, the stronger this response will be,” Cornwell said.
That affects the heart and blood vessels because the heart has to work harder, causing an increase in heart rate. Your cardiac output – the amount of blood your heart pumps per minute – will also increase, he said. “Basically, your body is attempting to compensate for the decrease in the quantity of oxygen available.”
“For most patients, hypoxia on a flight is comparatively mild,” says Luu Van Pham, assistant professor of medicine and pulmonology, critical care medicine and sleep medicine at Johns Hopkins Medicine in Baltimore. “Of particular concern are those people whose tolerance to hypoxia increases or decreases or whose lung disease worsens.”
People with sleep apnea or obstructive sleep apnea are at risk, especially if they drink alcohol during the flight. Alcohol worsens the condition: it has been proven to reduce the respiratory drive, relax the muscles in the mouth and throat and make it more difficult to wake up, which means that people with sleep apnea who drink alcohol on the plane have longer periods of difficulty breathing.
Emergencies during the flight
The CDC estimates that every year more than 4 billion passengers travel on commercial flights worldwide, or about 10 million per day. Every 604 of these flights, or 0.17%, medical emergencies, including fainting, heart problems, breathing problems, or nausea/vomiting.
Although this percentage is small, an in-flight incident presents challenges, especially on long-haul flights. Airplanes have limited medical equipment and, other than a Good Samaritan passenger, there are no dedicated medical personnel. Not to mention that “there isn’t a easy place for the aircraft to land and the response time of emergency personnel is delayed on account of obvious logistical issues,” Cornwell said.
Even if a plane finds a nearby airport, it can take up to 30 minutes to descend from cruising altitude. And the alternate airport may not be able to handle medical emergencies, adding extra time in situations where every minute counts.
Good advice: Don’t drink and don’t fly
Frequent travelers are probably used to seeing a travel doctor before visiting certain countries or remote locations. However, depending on the destination, the focus of travel medicine is often on preventing infections and infectious diseases. Common vaccinations target diseases such as tetanus, yellow fever and hepatitis B.
If you have heart or lung problems, you should see your GP before travelling to review your current medications, obtain additional prescriptions and discuss travel advice.
“If you might be having trouble respiratory and your oxygen saturation is borderline, consider bringing a small portable oxygen tank for the plane,” advises Dr. David Holmes, clinical associate professor of medicine and director of global health education at the Jacobs School of Medicine and Biomedical Sciences at the University of Buffalo, New York.
He said it's important to stay hydrated during the flight, regardless of your health status. “Dehydration could cause your heart rate to extend,” he explained. This is especially true in environments like an airplane cabin – with low humidity and frequent changes in air pressure – and when factors like fatigue are present.
Taking tranquilizers and sedatives before or during the flight can also increase the risk, as they place additional strain on the heart and affect oxygen saturation and heart rate. This is especially true when combined with alcohol.
Elmenhorst also noted that the study participants slept lying down. First and business class passengers, who have easier access to alcohol on board and lie-flat seats, may therefore be at greater risk than economy class passengers.
The solution? Don’t drink and fly.