This week I came across the results of a survey on traffic noise and its effects on people’s lives. The subjects were 2,612 residents of a small Swedish city whose homes were exposed to air, rail, and/or road traffic noise around the clock.
Overall, people whose bedroom windows faced a yard, garden, water, or green space reported having better sleep and concentration, and less annoyance at the noise, than people without a view of green space.
No way! I said to myself. Noise is noise. I don’t care if my bedroom window faces a Zen garden: if my Mack’s earplugs can’t block out the noise entirely, my sleep is toast. I’m no more tolerant of noise during the day, lumping leaf blowers, dirt bikes, and ATVs in the same category: obnoxious. There’s got to be something wrong with this survey.
Then I read further.
Compared with people who said they were not sensitive to noise, people who reported being very and extremely noise sensitive were 9 times more bothered by the traffic noise in their neighborhoods. It didn’t matter whether they had a window facing green space or not.
Noise Sensitivity and Insomnia
“Extremely noise sensitive” describes me to a T. And noise sensitivity is a liability when you’re prone to insomnia. If a conversation in the next room doesn’t keep you awake, clanking pipes surprise you just at the moment you’re ready to drift off. The water softener wakes you up when it comes on at 3. A diesel engine running outside your window can awaken you from the dead.
Is there an association between noise sensitivity and insomnia? I think there might be. As I was conducting interviews for my book, apartment dwellers and city people often complained that noise at night—whether from inside or outside their buildings—made their insomnia worse.
Anxiety and Vigilance
A cognitive model of insomnia suggests that the heightened sensitivity to noise that some insomniacs experience at night is in large part learned. People with chronic insomnia are often anxious about sleep. In turn, we become hyper-focused on everything we perceive as threatening to our sleep, whether internal, such as a jittery feeling, or external, like noise. Detection of noise or an irregular heartbeat jacks up our anxiety further, in turn making us more vigilant. We’re caught up in a vicious cycle of worry and vigilance that hinders our sleep ability.
As reasonable as this theory may sound, I’ve never been convinced that it explains my sensitivity to noise at night. I believe noise sensitivity is something I either inherited from my parents (musicians with keen ears) or developed early on as a result of their demand for absolute quiet at night.
More Than Learning May Be Involved
Some evidence suggests that the noise sensitivity associated with insomnia could be more like a stable trait. For instance, neuroimaging scans have detected wake-like activity in the brains of insomniacs even as we sleep. While we’re asleep, low-level information processing may be occurring in some areas of the brain. This would jibe with a susceptibility to being awakened by noise at night. It also calls into question the idea that noise sensitivity in insomniacs is wholly learned.
Studies involving evoked response potentials, or ERPs, show that people with insomnia may simply respond more forcefully to noise than normal sleepers. Our brains may register more excitement when auditory information goes in.
On the other hand, the sensitivity may have to do with how hard our brains are able to work to block noise out–something brains generally do in the sleep onset period and during sleep. As normal sleepers doze off, their brains have the ability readily to block out noise and disengage. Some ERP studies show that insomniacs’ brains have trouble inhibiting noise. Research also suggests that while good sleepers’ brains easily tune out repetitive noises such as the ticking of a clock, insomniacs “may have difficulties closing channels to non-pertinent stimulation.”
Whether noise sensitivity is learned or inborn, you want to do everything possible to minimize exposure to noise at night. A pair of earplugs is a good place to start.
What kinds of noise are you bothered by at night? How do you manage it?