Noise tends to be most disruptive in the light stages of sleep, which occur at the beginning of the night and in recurring periods throughout the night. It's also possible for noises to rouse you from deep sleep and REM sleep. To get a full night's sleep, it is important to protect your sleep environment against unwanted noise for the duration of your night's rest.
Noise at night can prevent you from falling asleep initially, and sounds during the night can wake you leaving you unable to return to sleep. Even noises that don't wake you can have a detrimental effect on sleep quality. The sleeping brain continues to register and process sound. Noises can create restlessness in sleep even if they don't wake you fully, and these interruptions affect sleep quality and the movement from lighter to deeper stages of sleep.
Individual responses to noise can vary significantly. Research suggests that certain patterns of activity in the brain are linked to higher tolerance for noise during sleep. Brains that generate higher concentrations of sleep spindles—bursts of high-frequency brain waves—have demonstrated greater resistance to noise during sleep. Sleep spindles first occur during Stage 2 sleep, a phase of light sleep that composes nearly half of a typical night's rest.
Familiar sounds tend to be less disruptive to sleep than new or unusual sounds. The sounds that occur regularly in our daily lives are ones that we give little attention, and don't create bother. This process of acclimating to sound is known as habituation, and happens at night as well as during the day. People in cities fall sleep to sounds of traffic every night—the same sounds that would likely keep rural dwellers wide awake. The absence of these sounds can actually make sleep harder—put a city sleeper in the country, and falling asleep might be more difficult amid the quiet. Reactions to sounds during sleep are also influenced by meaning and significance. Sounds indicating possible danger—even very quiet sounds, like the opening of a door—often will easily wake a sleeping person. Hearing their children cry usually causes parents to wake almost instantly. These responses to noise are highly individual, and a sign of how deeply engaged the brain remains to external stimuli during sleep.
As with all aspects of sleep, protecting against noise gets easier with a little bit of planning. If sound interferes with your sleep at night, there are adjustments you can make to reduce and regulate noise in your bedroom. Carpets and floor coverings, along with curtains on the windows can help muffle noise from outside, and from other areas of the house. Keeping windows closed also will limit noise from outside. Be sure to turn off all electronics before you turn in for the night.
White noise can help to block variable noises and provides constant, soothing sounds that can help you fall asleep and stay asleep throughout the night. White noise machines are designed for this purpose. Radio static, a running fan or an air conditioner can also provide this kind of mixed-frequency, pattern-less noise. Some people prefer familiar sounds, often from nature, such as breaking waves, crickets softly chirping, or wind rustling through leaves. Sound machines, CDs, and smartphone apps can provide these types of relaxing sound patterns to accompany you to sleep.
When you can't completely control the sounds around you, earplugs can help. Earplugs are comfortable and affordable way to limit noise disruption. When selecting earplugs, make sure they're soft and flexible. Earplugs are rated at decibel levels. Be sure to select earplugs that rated at no higher than 32 decibels (dB). These will block noise but still allow you to hear sounds that are important, such as a child crying, or your morning alarm.
Don't forget to take into account sounds of the early morning. A newspaper delivery, early traffic, neighbor's dog can disrupt sleep and shorten overall sleep time. In addition to making sure your sleep environment is quiet at bedtime, it also helps to protect against the intrusion of these early-morning noises.
Noise can undermine sleep, but it doesn't have to. Being aware of the noise-related disruptions to your sleep environment—and taking simple steps to reduce unwanted noise—will make your nightly rest more peaceful and rewarding.
Note: S+ is not a medical device. If you are seeking information on how to treat a sleep disorder, you should talk to your healthcare provider.