Sleep Disorders Sleep Latency: Definition, Testing, Results What to Know About Sleep Latency By Brandon Peters, MD Brandon Peters, MD Facebook Twitter Brandon Peters, MD, is a board-certified neurologist and sleep medicine specialist. Learn about our editorial process Updated on June 02, 2022 Medically reviewed Verywell Health articles are reviewed by board-certified physicians and healthcare professionals. These medical reviewers confirm the content is thorough and accurate, reflecting the latest evidence-based research. Content is reviewed before publication and upon substantial updates. Learn more. by Keri Peterson, MD Medically reviewed by Keri Peterson, MD Facebook LinkedIn Twitter Keri Peterson, MD, is board-certified in internal medicine and operates a private practice, Age Well, in New York City. Learn about our Medical Expert Board Print Sleep latency, also known as sleep onset latency or SOL, is the amount of time it takes to fall asleep when you go to bed. Ideally, it should take between 10 minutes and 20 minutes. Your sleep latency relates directly to sleep efficiency (the quality of your sleep) and sleep debt (how "behind" on sleep you are). An ideal sleep latency period lays the foundation for a solid night's sleep. Tetra Images / Getty Images Sleep Latency's Relation to Sleep Efficiency Sleep latency is related directly to sleep efficiency. That's because if you're able to fall asleep quickly, you're more likely to have efficient sleep. The two go hand in hand. Sleep specialists take the amount of time you spend asleep by the total time you spent in bed, then multiply it by 100. That gives them a percentage that's used to gauge your sleep efficiency. 90% or higher = extremely good85% = normalBelow 85% = poor Sleep Latency and the Sleep Cycle An ideal sleep latency lays the foundation for a solid night's sleep, which occurs in two basic states throughout the night. The two stages of sleep that occur throughout the night are rapid eye movement sleep (REM) and non-rapid eye movement sleep (NREM). REM sleep is a deeper form of sleep than most NREM sleep, but both states are directly impacted by sleep latency. If you have good sleep latency, you'll have a better chance of progressing through the stages of sleep comfortably and, in turn, enjoy a night of deep sleep. The Impact of Sleep Debt on Sleep Latency Sleep debt is the overall effect of not getting enough sleep. Sleep debt can accumulate over time and, in turn, lead to mental and physical fatigue. Sleep debt has a direct impact on sleep latency, since having a lot of sleep debt makes you extremely tired, meaning you'll likely fall asleep faster than someone who doesn't have any sleep debt. Many factors determine your sleep latency, and overall sleep debt is a big one. Falling asleep almost immediately upon laying down is often a sign of sleep debt and, therefore, a sign that you should try to get more sleep on a nightly basis. Was this page helpful? Thanks for your feedback! Tossing and turning night over night can have a big impact on your quality of life. Our free guide can help you get the rest you need. Sign up for our newsletter and get it free. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit 4 Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Jung DW, Hwang SH, Chung GS, Lee YJ, Jeong DU, Park KS. Estimation of sleep onset latency based on the blood pressure regulatory reflex mechanism. IEEE J Biomed Health Inform. 2013;17(3):534-544. doi:10.1109/jbhi.2013.2257816 Reed DL, Sacco WP. Measuring Sleep Efficiency: What Should the Denominator Be?. J Clin Sleep Med. 2016;12(2):263–266. doi:10.5664/jcsm.5498 Shrivastava D, Jung S, Saadat M, Sirohi R, Crewson K. How to interpret the results of a sleep study. J Community Hosp Intern Med Perspect. 2014;4(5):24983. Published 2014 Nov 25. doi:10.3402/jchimp.v4.24983 Goel N, Rao H, Durmer JS, Dinges DF. Neurocognitive consequences of sleep deprivation. Semin Neurol. 2009;29(4):320–339. doi:10.1055/s-0029-1237117