Getting good light exposure in the hours after waking primarily helps to:

• A. Induce rapid eye movement (REM) sleep during the day
• B. Increase melatonin production immediately after waking
• C. Regulate the circadian rhythm and promote alertness throughout the day
• D. Suppress cortisol release in the morning

Answer: (C)

Verified step by step guidance

1. Understand that light exposure after waking plays a crucial role in regulating the body's internal clock, known as the circadian rhythm.
2. Recognize that the circadian rhythm controls sleep-wake cycles and influences alertness and hormone production throughout the day.
3. Note that exposure to natural light in the morning helps signal the brain to reduce melatonin (the sleep hormone) and increase alertness.
4. Understand that this light exposure also helps synchronize the circadian rhythm, promoting wakefulness and optimal functioning during daytime hours.
5. Conclude that the primary effect of good light exposure after waking is to regulate the circadian rhythm and promote alertness, rather than inducing REM sleep during the day or increasing melatonin immediately after waking.