Final answer:
Circadian rhythms are 24-hour internal biological cycles governed by the biological clock, synchronized by light exposure, and influenced by factors such as nutrition and certain steroids. Light therapy is used to realign these rhythms, particularly in those with disrupted sleep-wake cycles due to work schedules or jet lag.
Step-by-step explanation:
Circadian rhythms are internal biological mechanisms that govern the sleep-wake cycle and other physiological processes within the body. These rhythms, with a periodicity of about 24 hours, are influenced by the biological clock located at the base of the brain. Aligned with the external environment's light-dark cycle, the circadian rhythm's clock is synchronized, in part, by the amount of light entering the eyes. Proper exposure to light and dark can maintain or restore this natural circadian synchrony, which is critical for overall well-being.
Individuals with disrupted circadian cycles, such as those who work night shifts or suffer from jet lag, may experience insomnia and symptoms of anxiety and depression. Utilizing bright light therapy, as shown in devices designed for this purpose, can help promote a regular sleep-wake cycle by providing the necessary light exposure to reset the biological clock. This therapy is aided by dark exposure during off-work hours, further enhancing the efficacy of realigning circadian rhythms.
It's important to consider that environmental factors like changes in light, nutrition, or the presence of certain compounds, such as dexamethasone, can disrupt the circadian clock. Regulating factors such as melatonin production in the pineal gland is stimulated by darkness, emphasizing the importance of managing light exposure for healthy circadian rhythms.