Biological Rhythms & Sleep

Ultradian Rhythm

Rhythms with periods longer than 24 hours, such as heart rate and multiple sleep cycles during the night.

Circadian Rhythm

Rhythms that have a cycle length of about 24 hours, exemplified by daily sleep-wake patterns.

Infradian Rhythm

Rhythms with cycles longer than 24 hours, such as the menstrual cycle.

Circannual Rhythm

Rhythms that repeat annually, such as hibernation.

Rhythm

A repeating event that occurs with a regular pattern.

Period

The duration of time it takes for one complete cycle of a rhythm to occur.

Phase

A marker or point within a daily rhythm.

Mesor

The average level of a rhythm across a complete cycle.

Amplitude

The difference between the peak and trough of a rhythm.

Frequency

How often a rhythm occurs within a specified period of time.

Zeitgeber

An external or environmental cue that synchronizes a biological rhythm.

Strongest Zeitgeber for Humans

Light

Endogenous Rhythm

A rhythm that is part of the particular organism and is innate.

Morning Lark

A person who is most productive in the early morning with higher energy.

Night Owl

A person who has higher energy and productivity later in the day or at night.

Reasons for Sleep

Repair of physical and mental energy, reduced energy demand, protection from predators, learning and memory plasticity, support for growth and development.

Stage 1 NREM

The lightest stage of sleep characterized by slowing heart rate, breathing, and eye movements.

Stage 2 NREM

most of time sleeping, drop in body temp, breathing slows, Waves: Sleep spindle = increase in activity in sleep, learning and memory is being worked on  

Sleep Spindle

A burst of brain activity during Stage 2 NREM indicating learning and memory processing.

Stage 3 and 4 NREM

Stages of deep sleep with decreased breathing and heart rate and slowed brain waves. (delta waves)

REM Sleep

Stage of sleep with irregular breathing, increased heart rate, and functions in memory consolidation and emotional processing.

Raphe Nuclei

Brain area that produces serotonin involved in sleep regulation.

Locus Coeruleus

Brain region that produces norepinephrine affecting alertness and wakefulness.

TMN

Hypothalamic area that secretes histamine and helps regulate wakefulness.

VLP

Sleep-promoting region that uses GABA and galanin to maintain sleep.

LDT/PPT

Brain region producing acetylcholine involved in wakefulness and sleep regulation.

VLPO

Area of the brain that promotes sleep and inhibits wakefulness.

Characteristics of Narcolepsy

Includes sudden sleep episodes with adequate nighttime sleep, frequent wakings during the night, and quick entry into REM sleep.

Obstructive Sleep Apnea

A condition characterized by intermittent pauses in breathing during sleep.

DST (Daylight Saving Time)

The practice of moving clocks forward or backward by one hour, which can disrupt sleep patterns and increase health risks.

Effects of Shift Work

Disruption of circadian rhythms leading to issues like heart problems, obesity, mental health issues, and digestive problems.

Sleep Hygiene Strategies

Practices to improve sleep quality, including consistent sleep schedules, avoiding screens before bed, keeping a cool dark room, and limiting alcohol and caffeine.