This study tested the effects of recorded hospital noises on the sleep quality in patients. One of the recorded noises had several fluctuations in volume which greatly decreased quality of sleep. One way to improve your sleep is to reduce the amount of random noises while sleeping – keep animals out of your room, shut off electronic devices, and utilize white noise strategies like fans or sleeping soundtracks.
Reference: Stanchina, M. L., Abu-Hijleh, M., Chaudhry, B. K., Carlisle, C. C., & Millman, R. P. (2005). The influence of white noise on sleep in subjects exposed to ICU noise. Sleep Medicine, 6(5), 423-428.