From the Guidelines
Morning wood, or nocturnal penile tumescence (NPT), is a natural and healthy phenomenon that occurs during sleep, particularly during REM sleep cycles, due to the increased activity of the parasympathetic nervous system and the suppression of anti-erection chemicals by the brain. This phenomenon is also influenced by the highest levels of testosterone typically present in the early morning [@\1@]. The presence of nocturnal and/or morning erections suggests, but does not confirm, a psychogenic component to erectile dysfunction (ED) symptoms, which would benefit from further investigation [@\1@].
Key Factors Contributing to Morning Wood
- The parasympathetic nervous system becomes more active during REM sleep, allowing blood to flow more freely into the penis and causing an erection.
- The sympathetic nervous system, which typically inhibits erections, becomes less active during REM sleep.
- Testosterone levels are typically highest in the early morning, contributing to morning erections [@\1@].
- The brain suppresses the release of anti-erection chemicals during sleep.
Clinical Significance of Morning Wood
- Morning erections are a good sign of physical health, indicating proper blood flow and nerve function in the genital area.
- The presence of morning erections can be an important factor in evaluating ED, as it may suggest a psychogenic component [@\1@].
- Men with ED should undergo a thorough medical, sexual, and psychosocial history, physical examination, and selective laboratory testing, including measurement of morning serum total testosterone levels [@\1@].
From the Research
Morning Wood Explanation
Morning wood, also known as nocturnal penile tumescence (NPT), is a common phenomenon where men experience erections during their sleep or upon waking. The exact cause of morning wood is not fully understood, but research suggests that it is related to various factors, including:
- Hormonal changes: Testosterone levels play a significant role in NPT, as studies have shown that hypogonadal men (those with low testosterone levels) experience decreased NPT and rigidity 1, 2, 3.
- Sleep patterns: NPT occurs during the rapid eye movement (REM) stage of sleep, and research has found that the frequency and quality of NPT episodes can be affected by sleep quality and duration 1, 4.
- Neurological factors: The brain's neurotransmitters and nervous system also contribute to NPT, as evidenced by the fact that NPT can occur independently of sexual arousal or stimulation 5, 2.
Factors Influencing Morning Wood
Several factors can influence the frequency and quality of morning wood, including:
- Age: Research has shown that NPT and rigidity decrease with age, with older men experiencing fewer and less intense erections 5.
- Testosterone levels: As mentioned earlier, testosterone plays a crucial role in NPT, and low testosterone levels can lead to decreased NPT and rigidity 1, 2, 3.
- Sleep quality: Poor sleep quality or duration can affect NPT, with research suggesting that adequate sleep is essential for healthy NPT 1, 4.
- Overall health: Certain medical conditions, such as erectile dysfunction or hypogonadism, can impact NPT and rigidity 1, 2.