Free-running sleep

Free-running sleep is a sleep pattern that is not adjusted (entrained) to the 24-hour cycle in a day but instead runs its own natural cycle. This pattern is often seen in people who are totally blind, as their retinas are unable to detect light, which is the main environmental cue for circadian rhythms.

Overview

Free-running sleep is a type of sleep disorder where a person's sleep-wake cycle gradually delays each day. This delay occurs because the individual's natural circadian rhythm is slightly longer than 24 hours. Without the influence of external cues, such as light exposure, to reset the biological clock, the sleep-wake cycle continues to delay each day.

Causes

The primary cause of free-running sleep is a lack of light exposure. Light is the main environmental cue (zeitgeber) that resets our biological clock each day. In the absence of this cue, the sleep-wake cycle runs its natural course, which is slightly longer than 24 hours for most people. This is often seen in people who are totally blind, as their retinas are unable to detect light.

Symptoms

The main symptom of free-running sleep is a sleep-wake cycle that gradually delays each day. This can lead to periods of insomnia at night and excessive sleepiness during the day. Other symptoms can include difficulty concentrating, decreased performance in work or school, and mood disturbances.

Treatment

Treatment for free-running sleep typically involves light therapy and melatonin supplements. Light therapy involves exposure to bright light upon waking to help reset the biological clock. Melatonin supplements can also help regulate the sleep-wake cycle.

See also

• Circadian rhythm sleep disorder
• Non-24-hour sleep-wake disorder
• Delayed sleep phase disorder
• Advanced sleep phase disorder