Study of how astronauts can maintain a healthy sleep cycle while in space, taking into account differences in light and gravity.
Anatomy and physiology of the sleep-wake cycle: The structure and functions of the brain regions, hormones, and neurotransmitters involved in regulating the sleep and wake periods.
Circadian rhythms: The circadian clock and its role in regulating the timing and duration of sleep-wake cycles, hormonal secretion, metabolism, and other physiological processes.
Sleep disorders: Common sleep disorders such as insomnia, sleep apnea, restless legs syndrome, and narcolepsy, their causes, and treatments.
Sleep hygiene: Strategies and lifestyle habits that promote healthy sleep patterns, including consistent sleep and wake times, avoiding caffeine and alcohol, and avoiding screen time before bed.
Sleep assessment and monitoring: Techniques for evaluating sleep quality, such as polysomnography, actigraphy, and subjective ratings.
Sleep deprivation and its effects: The consequences of chronic sleep loss on physical and mental health, cognitive function, and work performance.
Sleep in extreme environments: The challenges of maintaining healthy sleep patterns in space, submarines, and other environments with artificial light, noise, and altered gravity.
Pharmacology of sleep: The use of sleep aids, antidepressants, and other medications that affect the sleep-wake cycle, their indications, and side effects.
Chronobiology: The study of the biological rhythms of living organisms and their synchronization with environmental cues such as light and temperature.
Sleep in aging: The changes in sleep patterns that occur with aging, and strategies for promoting healthy sleep in older adults.
Sleep and mental health: The relationships between mental disorders such as anxiety, depression, and bipolar disorder, and sleep disturbances.
Sleep in shift work: The challenges of maintaining healthy sleep patterns for individuals who work overnight, rotating, or irregular shifts.
Ultradian rhythms: These are sleep and circadian rhythms that occur more than once in a 24-hour period. Examples of ultradian rhythms include the sleep cycle, which includes both REM and non-REM sleep, and the feeding cycle.
Infradian rhythms: These are sleep and circadian rhythms that occur less than once in a 24-hour period. An example of an infradian rhythm is the menstrual cycle.
Circadian rhythms: These are the body's natural 24-hour cycles, which regulate sleep and wakefulness, energy levels, and various other physiological functions. Circadian rhythms are driven by the body's internal clock, known as the suprachiasmatic nucleus (SCN), which responds to signals from the environment like light and temperature.
Lunar rhythms: These are sleep and circadian rhythms that are influenced by the phases of the moon. Some astronauts and researchers have reported changes in sleep and mood during full moons.
Social jet lag: This is a type of circadian rhythm disruption that occurs when someone's internal clock is disrupted by shifts in social schedules, such as staying up late to socialize on weekends and then waking up early during the week for work. This can lead to a mismatch between their internal clock and the demands of their external schedule.
Shift work disorder: This is a type of circadian rhythm disruption that occurs when someone's work schedule requires them to work during the night or early morning when their body is naturally programmed to sleep. This can lead to insomnia, fatigue, and other health problems.
Delayed sleep-wake phase disorder (DSWPD): This is a type of circadian rhythm disorder where the individual's internal clock runs slower than usual, so they naturally want to sleep and wake up later than usual. This can make it difficult to maintain a regular schedule or get up for school or work.
Advanced sleep-wake phase disorder (ASWPD): This is a type of circadian rhythm disorder where the individual's internal clock runs faster than usual, so they naturally want to go to bed and wake up earlier than usual. This can make it difficult to stay up late for social events or complete work or other tasks at night.
Non-24-hour sleep-wake disorder (N24): This is a type of circadian rhythm disorder where the individual's internal clock runs on a longer than 24-hour cycle, so their sleep times and wake times gradually shift later and later compared to the rest of the world. This can make it difficult to maintain a regular schedule or keep up with social and work demands.
Polysomnographic abnormalities: These are sleep disorders that are identified through in-lab testing, such as sleep apnea, REM sleep behavior disorder, and restless legs syndrome. Polysomnographic abnormalities can disrupt normal sleep and cause daytime fatigue and other health problems.