Some people with insomnia experience changes in their sleep cycles and, as a result, may have more stage 1 sleep and less deep sleep. Stress and aging can also reduce levels of deep sleep. Additionally, people with conditions such as schizophrenia and Alzheimer’s disease experience less slow wave sleep.

Consensus Conference Panel, Watson, N. F., Badr, M. S., Belenky, G., Bliwise, D. L., Buxton, O. M., Buysse, D., Dinges, D. F., Gangwisch, J., Grandner, M. A., Kushida, C., Malhotra, R. K., Martin, J. L., Patel, S. R., Quan, S. F., Tasali, E., Non-Participating Observers, Twery, M., Croft, J. B., Maher, E., … Heald, J. L. (2015). Recommended amount of sleep for a healthy adult: A joint consensus statement of the American Academy of Sleep Medicine and Sleep Research Society. Journal of Clinical Sleep Medicine, 11(6), 591–592. 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.

When should you buy a mattress?

To calculate how much deep sleep you need, first determine how much sleep you need overall. Most adults should aim for at least seven hours Change your diet: What you eat and drink before bedtime impacts your sleep. One small study found that people eating a diet high in saturated fats obtained less slow-wave sleep

to vaccines and leave you more vulnerable to infection. During deep sleep, potentially harmful waste products are eliminated from the brain. As a result, disruptions to deep sleep may also drive advancement of neurological conditions such as Alzheimer’sOnce you fall asleep, your body cycles through three non rapid eye movement (NREM) stages of sleep followed by one rapid eye movement (REM) stage. It usually takes between 90 and 120 minutes 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.

Typically you descend into deep sleep within an hour of falling asleep, and experience progressively shorter periods of deep sleep as the night wears on. During this stage, automatic body functions like breathing and heart rate are also very slow and your muscles are relaxed. It can be difficult for someone to wake you up, and waking up out of deep sleep may make you feel mentally foggy for up to an hour. How Much Deep Sleep is Enough?

How do you know when you need a new mattress? How often should you change your mattress?

The Sleep Foundation editorial team is dedicated to providing content that meets the highest standards for accuracy and objectivity. Our editors and medical experts rigorously evaluate every article and guide to ensure the information is factual, up-to-date, and free of bias. Halson, S. L., & Juliff, L. E. (2017). Sleep, sport, and the brain. Progress in Brain Research, 234, 13–31. 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