When boarding long-haul flights, many of us are tempted to enjoy a drink and take a nap. However, this common practice may be putting our hearts under extra pressure, according to a new study by researchers at the Institute of Aerospace Medicine at the German Aerospace Center.
DRINKING AND SLEEPING ON LONG-HAUL FLIGHTS ; THE STUDY SETUP
The research team conducted an experiment involving 40 volunteers, split between two sleep lab chambers. One chamber maintained normal ground-level pressure, while the other simulated the pressure experienced at an airplane cruising altitude of approximately 2,438 meters (or around 8,000 feet). This setup aimed to investigate the combined impact of alcohol consumption and sleep at high altitudes.
DRINKING AND SLEEPING ON LONG-HAUL FLIGHTS ; UNDERSTANDING HYPOBARIC HYPOXIA
At higher altitudes, the lower oxygen levels lead to a condition known as hypobaric hypoxia, where blood oxygen levels (SpO2) begin to drop. The new research highlights that combining hypobaric hypoxia with alcohol consumption and sleep can be particularly dangerous.
“This study is the first to investigate the combined impact of hypobaric hypoxia and alcohol during sleep,” the researchers wrote in their published paper. “We show that the on-board consumption of alcohol is an underestimated health risk that could be easily avoided.”
Experimental Groups and Findings
The study divided participants into four groups:
Those sleeping at normal pressure without alcohol.
Those sleeping at normal pressure with alcohol.
Those sleeping at cabin pressure without alcohol.
Those sleeping at cabin pressure with alcohol.
Participants who consumed alcohol were given the equivalent of two cans of beer or two glasses of wine. Each participant was limited to four hours of sleep per night to mimic the experience of disrupted sleep during flights.
DRINKING AND SLEEPING ON LONG-HAUL FLIGHTS ; KEY FINDINGS:
- Normal Pressure with Alcohol: Participants had an average blood oxygen level of 94.97 percent and a heart rate of 76.97 beats-per-minute (bpm).
- Normal Pressure without Alcohol: Participants had a blood oxygen level of 95.88 percent and a heart rate of 63.74 bpm.
- Reduced Pressure with Alcohol: Participants had an average blood oxygen level of 85.32 percent and a heart rate of 87.73 bpm.
- Reduced Pressure without Alcohol: Participants had a blood oxygen level of 88.07 percent and a heart rate of 72.90 bpm.
The data suggests that under airplane cabin conditions, both blood oxygen levels were lower, and heart rates were higher compared to the control group. These effects were more pronounced among those who consumed alcohol.
DRINKING AND SLEEPING ON LONG-HAUL FLIGHTS ; HEALTH IMPLICATIONS
These results are significant because the healthy clinical norm for SpO2 is 90 percent. The combination of reduced SpO2 and elevated heart rate can put extra strain on the cardiovascular system, potentially increasing the risk of heart problems, particularly for those with existing health conditions.
Furthermore, the study found that these factors also reduced the time spent in deep and REM sleep, both crucial for overall sleep quality.
DRINKING AND SLEEPING ON LONG-HAUL FLIGHTS ; BROADER IMPLICATIONS AND FUTURE RESEARCH
While the study had a small sample size and involved only young, healthy individuals, the implications for older and more vulnerable populations could be even more pronounced. This is an area that future research could explore further.
DRINKING AND SLEEPING ON LONG-HAUL FLIGHTS ; RECOMMENDATIONS FOR TRAVELERS
Although it might be tempting to have a drink and take a nap on a long-haul flight, the researchers urge travellers to reconsider these habits. “Public awareness of this topic should be raised through patient charities, public campaigns, and written health advice of airlines,” the researchers advised. They noted that technical and economic constraints make it unlikely that airlines will increase cabin pressure.
The study, published in the journal Thorax, highlights a significant but often overlooked health risk associated with drinking and sleeping on flights. As we become more aware of these risks, it is essential to adjust our in-flight habits to protect our cardiovascular health, especially during long-haul flights.