As people age, they tend to have less deep sleep. Older adults usually get more stage 2 sleep instead.

Stage 3: Stage 3 sleep represents the deepest sleep of the sleep cycle, when brain waves are at their slowest in frequency and highest in amplitude.to cycle through all four stages, after which the cycle starts again. Adults typically have four to six cycles per night. In the first half of the night you spend more time in NREM sleep. However, as the night goes on, you spend more and more time in REM sleep. A member of our medical expert team provides a final review of the content and sources cited for every guide, article, and product review concerning medical- and health-related topics. Inaccurate or unverifiable information will be removed prior to publication. Besedovsky, L., Lange, T., & Born, J. (2012). Sleep and immune function. Pflügers Archiv: European Journal of Physiology, 463(1), 121–137.

American Academy of Sleep Medicine (AASM) AASM sets standards and promotes excellence in sleep medicine health care, education, and research. View Source Ju, Y. S., Ooms, S. J., Sutphen, C., Macauley, S. L., Zangrilli, M. A., Jerome, G., Fagan, A. M., Mignot, E., Zempel, J. M., Claassen, J., & Holtzman, D. M. (2017). Slow wave sleep disruption increases cerebrospinal fluid amyloid-β levels. Brain: A Journal of Neurology, 140(8), 2104–2111. or memory center of the brain, experience much less slow wave sleep than people with an undamaged hippocampus. Experts propose that the memory signals sent by the hippocampus are a necessary trigger for creating the slow delta waves seen in deep sleep. Accordingly, problems with memory formation may represent a cause, rather than a consequence, of less deep sleep.Additionally, sleep deprivation is associated with hormonal changes that drive our appetite for high-calorie food. Going short on slow-wave sleep, in particular, is believed to contribute to insulin resistance and the development of type 2 diabetes and heart disease. Catching up on sleep may reverse some of these effects