Sexual Arousal In Sleep: Gender Differences Explored

Sleep is a complex process that involves various stages, including REM (rapid-eye movement) and non-REM sleep. During the REM stage, the eyes move rapidly, and the body is temporarily paralysed, except for the eye muscles and diaphragm. This is also the stage where dreams occur. Arousal during sleep can occur in either of these stages and is caused by a change in brain wave activity, which can be measured by an EEG (electroencephalogram test). Arousal typically represents a shift from deep sleep to light sleep or from sleep to wakefulness.

Sexsomnia is a parasomnia characterised by sexual behaviour during sleep. It occurs during non-REM sleep, and those experiencing it generally have no recollection of the event upon waking. It can lead to various consequences, including clinical, interpersonal, and legal. Sexsomnia is often associated with other parasomnias, such as sleepwalking and confusional arousals, and can be triggered by sleep disorders like sleep apnoea and periodic leg movement disorder.

Research suggests that sleep deprivation can increase sexual arousal in both men and women, although it does not seem to increase sexual frequency. A study found that REM sleep deprivation increased erections in male rats and audiovisual sexual stimulation in men. However, the effects of sleep problems on unstimulated sexual arousal in humans are still not fully understood.

Arousal during REM sleep

REM sleep is a deep stage of sleep with intense brain activity in the forebrain and midbrain. It is characterised by dreaming and the absence of motor function, except for the eye muscles and the diaphragm. It occurs cyclically several times during sleep but comprises the smallest portion of the sleep cycle. Arousal during REM sleep occurs specifically during non-REM sleep. During non-REM sleep parasomnias, after an event, the sleeper usually goes back to sleep and does not recall their behaviours. Other non-REM parasomnias include sleepwalking, sleep-related driving, and sleep-related eating disorders.

Sexsomnia is a form of parasomnia characterised by sexual behaviour during sleep. It occurs in young adults and is characterised by masturbation and inappropriate attempts at achieving sexual intercourse followed by total amnesia of the events. It can be associated with other parasomnias such as sleepwalking and confusional arousals. Other sleep disorders, including sleep apnoea and periodic leg movement disorder, may trigger episodes of sexsomnia. Sexsomnia has been reported to be associated with the following characteristics:

• A history of parasomnias, such as sleepwalking
• Sleep fragmentation, which can be caused by other sleep disorders like obstructive sleep apnoea and restless leg syndrome
• A history of substance abuse
• A history of trauma or abuse
• A history of depression
• Use of sleeping pills

Arousal during sleep is not uncommon, but most people fall asleep within a few minutes and don't remember it. Arousal can become an issue if it occurs frequently, preventing some people from getting a solid night's sleep and enough deep sleep.

Arousal during non-REM sleep

The clinical spectrum of arousal during non-REM sleep is illustrated by four cases:

Case 1

A 38-year-old man presented with a 7-year history of abnormal behaviour during sleep. He reported isolated incidents of sleep talking as a child. He had been in a stable relationship for 17 years and the couple had a daughter. They engaged in conventional and satisfactory sexual intercourse with a frequency of 2-3 times weekly. The patient's wife reported that in the past 7 years, her husband would sleep for 2-3 hours at night before presenting abrupt 10- to 30-minute episodes in which he would attempt to achieve coitus. He experienced such an episode approximately once a week. In contrast to his behaviour when awake, he used vigorous movements and lewd language while attempting to persuade and penetrate his partner. The patient had awakened in a confused state during some of these episodes and was surprised by his wife's account of his behaviour. The patient and his partner were unable to link these episodes to any trigger factors such as stress or prior sexual stimuli. He never recalled what had happened the following morning. The patient did not typically remember his dreams, but he did occasionally experience erotic dreams accompanied by spontaneous ejaculation. However, these dreams never coincided with the episodes he described in the consultation. In addition to episodes of arousal during non-REM sleep, he had a 20-year history of snoring, apnoeic episodes observed by his wife, and excessive daytime drowsiness. The patient presented an Epworth Sleepiness Scale score of 14 and a body mass index of 25. A nocturnal polysomnography study with audio-visual recording was indicative of obstructive apnoea episodes associated with oxyhaemoglobin desaturation and micro-arousals causing broken sleep. The global apnoea/hypopnoea index for obstructive episodes was 13/hour, reaching 40/hour when the patient was supine. The study detected no other abnormalities, such as epileptiform activity or abnormal sleep behaviours such as those described during episodes of arousal during non-REM sleep or other types of parasomnia. The patient refused treatment for sleep apnoea as well as clonazepam treatment for arousal during non-REM sleep.

Case 2

A 41-year-old woman made an appointment due to a 1-year history of atypical sexual behaviour. She had presented childhood sleepwalking until the age of 14. Her husband explained that in the past year, she had been masturbating about 3 times per week without seeking to involve him although they slept in the same bed. She did not remember these episodes upon waking up the next morning. They occurred around 5.00 and sometimes resulted in orgasm, to the surprise of her husband, who never participated in his wife's episodes. When her husband described these episodes, she felt ashamed and stated that she was unable to remember them. She reported that they had regular, satisfactory, and pleasant sexual intercourse, with no sexual problems when awake. In addition, her husband also indicated that she displayed repetitive and periodic non-sexual limb movements while sleeping, especially when in the lateral decubitus position. The patient explained that when she was awake she occasionally presented a sensation of restless legs when resting, especially at night, which did not interfere with her ability to fall asleep when she went to bed. She did not snore and no apnoeic episodes were detected during sleep. Likewise, she presented no excessive daytime drowsiness or insomnia. A polysomnography study with audio-visual recording identified periodic leg movements during sleep. The study showed an index of 24 movements per hour, occurring throughout the night. An index of 7 periodic leg movements per hour was associated with microarousals resulting in partially broken sleep. Apart from affecting the patient's feet, the characteristic feature of these movements was their association with sudden abduction of the lower limbs. On 2 occasions, these movements were more prolonged, accompanied by repetitive arm movements. She also placed her hand on her genitals for a few seconds but did not masturbate. No apnoeic episodes,

Arousal and testosterone levels

There is a link between sexual arousal and testosterone levels, with arousal increasing in both men and women with higher testosterone levels. However, the relationship is complex and varies with other factors.

Arousal and testosterone in men

REM sleep deprivation has been shown to increase unstimulated erections in male rats, and total sleep deprivation increases erections in men during audiovisual sexual stimulation. In a study, men with higher testosterone levels and poorer sleep quality were found to have greater unstimulated sexual arousal.

However, another study found that sexual thoughts in men did not change testosterone levels compared to control conditions.

Arousal and testosterone in women

Poorer sleep quality has been correlated with greater unstimulated sexual arousal in women with higher testosterone levels who are not taking oral contraceptives.

In a study of women in long-distance relationships, testosterone levels were highest in anticipation of sexual activity and the day after sexual activity. However, testosterone levels declined in the presence of their partner before any sexual activity.

Another study found that sexual thoughts did not change testosterone levels in women compared to control conditions.

Testosterone treatments for low sexual desire

Treatments with exogenous testosterone or the adrenal hormone dehydroepiandrosterone (DHEA) have been prescribed for women with low sexual desire. These treatments have been effective in some women with abnormally low testosterone levels but not in women with normal testosterone levels. There are also often unwanted side effects of testosterone administration, such as facial hair and acne.

Arousal and oral contraceptives

Oral contraceptives have been shown to have an impact on female sexual function, with studies indicating that they can both positively and negatively affect different aspects of female sexuality. However, the evidence is inconsistent, and more research is needed.

Oral contraceptives have been found to decrease circulating androgen, estradiol, and progesterone levels, as well as inhibit oxytocin functioning. This can lead to a reduction in libido and sexual desire. However, some studies have found no change in sexual function with oral contraceptives, and others have found that they can have a positive impact on sexual desire, orgasm, satisfaction, and arousal.

The impact of oral contraceptives on female sexual function may depend on the type of oral contraceptive and its hormonal composition. For example, oral contraceptives with antiandrogenic progestins do not appear to affect sexual desire. Newer progestins have little or no androgenic activity, while others have antiandrogenic activity. Oral contraceptives with more "physiological" forms of estrogen, such as 17β-estradiol or estradiol valerate, may also have a more positive impact on female sexual function.

The vaginal ring and the patch are other forms of hormonal contraception that have been studied for their effects on female sexual function. The vaginal ring has been found to improve sexual desire, fantasies, and satisfaction, while the patch has been associated with slight increases in sexual function scores. However, more research is needed to confirm these findings.

When oral contraceptive-related sexual dysfunction is suspected, the recommended therapy is discontinuation of the oral contraceptive and consideration of an alternative method, such as a levonorgestrel-releasing intrauterine system, a copper intrauterine device, an etonogestrel implant, permanent sterilization, or a contraceptive ring.

Oral Contraceptives and REM Sleep

There is limited research on the direct impact of oral contraceptives on REM sleep. However, one study found that oral contraceptives seem to facilitate REM sleep. This may be because oral contraceptives can influence the amount and cyclicity of menstrual bleeding, which can affect sleep.

Arousal and sleep disorders

Arousal during sleep is caused by a change in the pattern of brain wave activity, which can be measured by an EEG. Arousal typically represents a shift from deep sleep to light sleep or from sleep to wakefulness. Arousal can occur during any stage of sleep and is more common between stages. Arousal during sleep is not uncommon, and most people fall back asleep within a few minutes and don't remember it. However, it can become an issue if it occurs frequently, preventing some people from getting a good night's sleep and enough deep sleep.

Sleep occurs in two basic states: rapid eye movement sleep (REM) and non-rapid eye movement sleep (NREM). Arousal occurs more often during states of NREM sleep, which consists of three separate stages: N1, N2, and N3. Each separate state has unique, distinct, and recognizable electrical brain wave patterns. Stage 3 (N3) of NREM sleep is the deepest stage of sleep.

REM sleep is a deep stage of sleep with intense brain activity in the forebrain and midbrain. It is characterised by dreaming and the absence of motor function, except for the eye muscles and the diaphragm. It occurs cyclically several times during sleep but comprises the smallest portion of the sleep cycle.

REM sleep deprivation increases spontaneous erections in male rats, and total sleep deprivation increases erections in men during audiovisual sexual stimulation. Poorer sleep quality has been correlated with greater unstimulated sexual arousal in men with higher testosterone levels and in women with higher testosterone levels who are not taking oral contraceptives. In women with lower testosterone levels, poorer subjective sleep quality is correlated with greater sexual dissatisfaction. However, in both sexes, sleep quality is unrelated to sexual desire and sexual frequency over the past month.

Sexsomnia is a parasomnia characterised by sexual behaviour during sleep. It occurs in young adults and is more common in men than in women. It consists of masturbation or inappropriate attempts to achieve sexual intercourse, followed by total amnesia of the events. Sexsomnia may be associated with other parasomnias such as sleepwalking and confusional arousals. Other sleep disorders, including sleep apnoea and periodic leg movement disorder, may also trigger episodes of sexsomnia.

The diagnosis of sexsomnia is completed by an overnight sleep study at a sleep centre, where an electroencephalogram (EEG) is used to test brain activity and rule out possible seizures. The remaining measures of the nocturnal polysomnogram (PSG) monitor abrupt and spontaneous arousals during slow-wave sleep and rule out epileptic disorders. Behaviour is closely watched and recorded, and clear descriptions of sleep behaviours from bed partners are helpful in diagnosis.

As sexsomnia is associated with other sleep disorders, addressing the underlying cause can lead to substantial improvement. Some cases have reported positive results from using continuous positive airway pressure (CPAP) or an oral appliance to treat underlying obstructive sleep apnoea. Antidepressants, such as selective serotonin reuptake inhibitors that increase serotonin levels in the brain, as well as clonazepam, have also been used to treat sexsomnia.

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