December 27, 2023 – Sleep deficiency is a global issue. Nowhere is this more evident than in Omagh, a small town in Northern Ireland, where residents have been kept awake since September by a persistent, ongoing hum or drone at night, often accompanied by vibration.
Reports of hum-related sleep disturbances are not a new phenomenon. Glen MacPherson, PhD, former lecturer at the University of British Columbia and current mathematics teacher and ethnographer at a high school, has been tracking the so-called „Worldwide Hum“ since encountering it in 2012. „It sounds like a distant idling car outside your house,“ he said. „Some people describe it as a faint droning or low rumble.“
However, MacPherson – whose
World Hum Map
shows the thousands of people who believe they’ve heard the noise – indicated that only 2 to 4% of people can hear the real „worldwide hum.“ More importantly, he said what likely disturbs the sleep of Omagh residents and indeed a large percentage of people living in densely populated areas is low-frequency noise (LFN). LFN sources are mostly man-made or industrial and include ventilation systems, traffic, airplanes, and wind turbines.
„The human ear is only capable of hearing a small range of sounds,“ said Jeff Ellenbogen, MD, neurologist, sleep specialist, and director of the Sound Sleep Project in Baltimore. „Low-frequency noise refers to sounds (in this case undesired sounds) that occur below 250 Hz,“ he said, adding that it is often more noticeable at night when overall noise levels are lower and people are trying to sleep.
The cost of sleep deficiencies
To be fully functional, adults need an average of at least 7 hours of sleep per night, preferably uninterrupted, while going through light and deep stages (which usually occurs about four to six times). Studies have shown that environmental noises disrupt sleep and can lead to increased levels of stage 1 light sleep and decreased slow-wave sleep, as well as rapid eye movement (REM) sleep, when most of our dreams occur, said Michelle Drerup, PsyD, director of the Behavioral Sleep Medicine Program at the Cleveland Clinic.
Although low-frequency noise is not fully understood by sleep researchers, it seems to have a wide range of interrelated consequences. „Chronic exposure to background noise (especially road, rail, and aircraft traffic) leads to changes in heart rhythms and heart disease,“ said Shannon Sullivan, MD, clinical professor of sleep medicine at Stanford University in San Francisco and a spokesperson for the American Academy of Sleep Medicine. Chronic noise exposure is also linked to depression, anxiety, an increase in stress hormones, and even structural changes in the brain.
Short-term, these noises, often perceived as more disruptive than regular noise, can lead to irritability and fatigue. „When we get less slow-wave and REM sleep, people feel less restored, and it impairs memory. Over time, this can affect perception,“ said Drerup.
Unfamiliar environments, unfamiliar sounds
There is no doubt that low-frequency noise is becoming a worldwide problem. In 2022, the World Health Organization issued guidelines on the health effects of this type of environmental noise, as well as recommended measures for raising awareness and ways to mitigate resulting diseases. However, according to various sleep experts, even short-term or limited stress, as experienced when traveling on vacation to visit family or friends, can impact sleep quality.
„When traveling through time zones, it’s not just a challenge for the environment, but also for the body’s rhythms,“ said Sullivan. „For example, someone traveling from the West to the East Coast will challenge their normal circadian rhythm by three hours, which will affect sleep quality.“
She also points out travel to visit family, when „sleep conditions may not be as comfortable as we are used to.“ Sullivan said there are ways to minimize the effects of low-frequency noise and other issues on our sleep, whether sleeping in unfamiliar or uncomfortable beds or dealing with noise in a hotel or rental property.
Admittedly, just as sleep preferences are up to the individual, so are the ways to ensure a good night’s rest. Generally, according to Sullivan, it is important to maintain a reasonably steady wake time when traveling across time zones and to expose oneself to some sun or light upon waking up. When it’s time to sleep, she recommends a dark sleeping environment. „Try an eye mask – especially when crossing time zones and light is coming at your brain at the wrong time.“
Drerup said that when there is time to adjust to a new time zone before traveling, she often recommends one of the new
smartphone apps
that provide a detailed plan on when to start shifting, when to sleep on the plane, when to seek or avoid light, as well as meal planning.
„Earplugs or masking noises are also becoming increasingly important while on the go,“ said Ellenbogen. While not everyone finds earplugs comfortable, he recommends the soft variety with a noise reduction of at least 30 dB for those who can tolerate them.
David Neubauer, MD, sleep medicine specialist and associate professor of psychiatry and behavioral sciences at Johns Hopkins Medicine Bayview Medical Center in Baltimore, said he personally prefers to mask noises with a bedroom fan or a portable device while traveling, creating a fan-like sound. There are also smartphone apps that play masking sounds, helping to divert the auditory focus from unwanted noises. „Find a sound that feels soothing while awake,“ he said. „Play it at a volume that is not distracting but ensures that unwanted noises are barely audible. And remember to turn off other alarms when going to bed.“
„The way we sleep dictates or influences how we feel during the day, especially during holidays when being together is a time of great joy and activity, but can also be stressful,“ said Sullivan. „Good sleep quality is one of the things that can help reduce stress and bring out our best.“