The feeling of drowsiness after ejaculation is regulated by hormonal factors, nerves, energy consumption, and the sympathetic nervous system reduces activity to help the body relax.
According to Dr.BS.CK2 Tra Anh Duy, Member of the International Society for Sexual Medicine (ISSM), after ejaculation, men often feel sleepy or relaxed, which is a normal physiological phenomenon, not normal. It must be coincidental but has a scientific basis. Here are the main reasons explaining this phenomenon:
Hormone release
Ejaculation and orgasm are experiences that are accompanied by the release of a series of hormones in the body, which have the effect of making men feel sleepy and relaxed:
Oxytocin
Known as the “love hormone,” oxytocin is released after orgasm, helping to create feelings of intimacy and relaxation. Oxytocin not only helps strengthen emotional connection but also has a calming and relaxing effect on the body.
Prolactin
After ejaculation, prolactin levels in the body increase suddenly. Prolactin is associated with feelings of satisfaction and sleepiness.
A study published on Journal of Sexual Medicine indicates that prolactin is directly related to feelings of fatigue and sleep after sex.
Serotonin
This is an important neurotransmitter in the brain that controls emotions, mood, and sleep.
After orgasm, serotonin levels increase, causing a feeling of deep relaxation and contributing to drowsiness. Serotonin is also involved in the production of melatonin, the hormone that regulates sleep cycles. This helps explain why men find it easier to fall asleep immediately after having sex or ejaculating.
Vasopressin
Another hormone, vasopressin, is released along with oxytocin after orgasm. Vasopressin has a sedative effect, helping men feel comfortable and fall asleep easily.
Energy consumption
Sexual intercourse and the ejaculation process consume a significant amount of energy, especially with the participation of many muscle groups and increased blood circulation.
The body uses energy during sex, especially during orgasm, making men feel tired and need to recover with sleep.
After sex, men feel tired and need to recover with sleep. Image: SCMP
Reduced activity of the sympathetic nervous system
After orgasm and ejaculation, the body switches from a state of excitement (controlled by the sympathetic nervous system) to a state of relaxation (controlled by the parasympathetic nervous system). The decrease in sympathetic nervous system activity causes the body to become more relaxed and prepare for a state of rest.
Reduce stress and anxiety levels
Sex and ejaculation have the ability to reduce stress, anxiety, and even pain thanks to the release of endorphins – the body’s natural pain relievers. This not only helps men feel lighter and more comfortable, but also increases the feeling of wanting to go to sleep so the body can completely rest.
Differences between men and women
Studies show that feeling sleepy after sex is more common in men than in women. Part of the reason is that men go through a refractory period after ejaculation, during which they can no longer reach orgasm immediately. This time can last from a few minutes to several hours or even longer, depending on each person’s age and physical condition. During this stage, the body often falls into a sleepy state.
Effects of testosterone
Testosterone is a hormone that plays an important role in sexual activity in men, helping to maintain desire and erectile ability. However, after ejaculation, testosterone levels in the body can temporarily decrease, making men feel tired and sleepy.