Q. My husband goes to sleep straight after sex while I’d rather have a cuddle. I know it’s a cliché, but is there a biological reason why it happens?
Although it doesn’t immediately spring to mind as a serious subject for scientific investigation, there is, in fact, a wealth of research devoted to the male propensity to fall asleep after sex. Basically, ejaculation and orgasm flood the brain with a cocktail of neuro-chemicals (norepinephrine, serotonin, oxytocin, vasopressin, nitric oxide and prolactin) that collectively contribute to feelings of satiety and satisfaction after sex. The release of oxytocin and vasopressin often coincide with the production of melatonin, the hormone that regulates the body clock, while the hormone prolactin is directly associated with sleep and relaxation. In men, prolactin also mediates the “refractory period”, the time it takes to recover from orgasm and regain the ability to have an erection.
It’s not just men who feel sleepy after sex as orgasm leads to an escalation in the secretion of prolactin in both genders. However, there are competing theories as to whether an orgasm induced by masturbation produces as much as an orgasm induced by intercourse. One study has suggested that prolactin increases to levels of between 15 and 25ng/ml for at least one hour after an orgasm achieved by either coitus or masturbation, while another more recent study suggests the magnitude of prolactin increase after intercourse is 400% greater than that following masturbation.
Either way, prolactin appears to wrap the mind and body in a fuzzy blanket of sleep — anyone who has had early morning sex followed by a blissful, and mutual, postorgasmic coma would agree that this is, in general, no bad thing. Problems arise when one partner goes out like a light and the other is left staring at the ceiling. It is an inequity that has been explored by Krüger et al in a paper published in 2011. Although previous research had demonstrated that men tend to fall asleep first after sex, Krüger and his co-author, Susan Hughes, did not find evidence to support that prediction. They did find that, like you, participants in the study whose partners tended to fall asleep first would prefer it to happen less often. They also expressed a greater desire for more expressions of emotional bonding and communication from their partner. In other words they, too, wanted a cuddle after an orgasm.
Other evidence of the relaxing properties of orgasm comes from research using positron emission tomography (PET) scans. Neuroscientist Gert Holstege at the University of Groningen in the Netherlands has shown that during orgasm, activity in the amygdala, the part of the brain that is responsible for alertness, anxiety and fear, is deactivated. Holstege believes this explains why people who feel anxious or fearful find it virtually impossible to achieve orgasm. The opposite is true for people who do experience orgasm, because to do so, they have to let go of stress and tension and this, in turn, leaves them feeling relaxed and sleepy.
Orgasm is obviously not the only way to alleviate stress. Cuddling and touch of any sort are tremendously important for health and wellbeing. A 2008 study of married couplesfound that daily touching lead to an increase in salivary oxytocin and a reduction of alpha-amylase, a biomarker for stress in both partners. Husbands in the intervention group also had significantly lower 24-hour systolic blood pressure compared with the control.
Cuddling helps couples to feel more intimately connected, but there is no reason why it has to happen post-coitally. Before sex, your husband’s attention is intensely focused on physical contact with you, so foreplay is the perfect time to slow things down and incorporate as much cuddling, kissing and emotional bonding as you like. Similarly, being tactile with each other throughout the day is associated with greater satisfaction with the relationship. Because the tendency to sleep after sex is biologically programmed, preventing your husband from having 40 winks after sexual activity will be more difficult if you have sex at night, in a comfy bed, after a couple of glasses of wine. Try changing the time and the venue. It he is less tired and less comfortable, he is less likely to go to sleep. Realistically, you are not going to want to have sex on the kitchen table every time, so you will have to continue to accommodate his need to sleep. However, try to keep it in perspective. You are not married to one of the 48% of men who, in a 2012 survey of 10,000 Britishadults, admitted to falling asleep during sex.
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