Sleep and sexuality
Studies with animal models indicate a correlation between sleep deprivation and the release of ovarian hormones

By José Tadeu Arantes

Monica Levy Andersen, a researcher at the Sleep Institute – one of the Research, Innovation and Dissemination Centers (RIDCs) funded by FAPESP from 2000 to 2013 – studied the influence of sleep on sexual behavior using animal models. “We discovered that sleep deprivation in rats caused hormonal changes according to the phase of the menstrual cycle they were in when subjected to this condition, indicating a correlation between sleep and the release of ovarian hormones.”

Thus, rats in the phase after heat when the female rejects the approach of any male, when subjected to a protocol of paradoxical sleep deprivation (PSD) for 96 hours, experienced an interruption in their menstrual cycles and remained in anestrus (sexual inactivity) for 10 days (Antunes et al, 2006). These females also experienced a significant increase in corticosterone and a reduction in estradiol compared with the control rats in the same phase of the menstrual cycle, in addition to alterations in sleep patterns (Andersen et al, 2008), the researcher reports.

The group also studied the sexual behavior of rats subjected to sleep deprivation during specific phases of the menstrual cycle and demonstrated that during the pro-estrus phase (the period that precedes the reproductive or estrus phase), there was an increase in proceptivity (explicit manifestation of sexual desire) and receptivity (acceptance of copulation with the male). However, when sleep deprivation occurred during the phases of estrus and diestrus, the researchers noted an increase in rejection behaviors towards males (Andersen, Alvarenga et al, 2009).

Post-menopausal insomnia was also investigated. One of the alternative medicines proven effective for treating insomnia is isoflavone, a phytotherapy supplement used to mitigate the symptoms. “We observed that isoflavone reduced the frequency and intensity of vasomotor and insomnia symptoms when compared to the placebo in a controlled double-blind randomized study (Hachul et al, 2011),” says Helena Hachul, head of the Climacteric Sleep Disturbances Clinic at Federal University of São Paulo (UNIFESP).

These initial findings were later complemented by a controlled randomized study (Souza et al. 2012) in which post-menopausal women with insomnia were separated into three groups: a control group, a group that received stretching exercises, and a group that received therapeutic massage. “The results showed that the best treatment was massage,” the researcher explains. 

In another study, the therapeutic effects of yoga on post-menopausal women with insomnia were studied (Afonso et al, 2012). As in the previous case, the women were divided into three groups (control, stretching and yoga), and the same parameters were observed, with the findings again pointing to yoga, as Helena Hachul concludes. The use of acupuncture and meditation techniques has also been studied, with positive results for treating insomnia in both cases (Garcia et al, 2013, in print).

Risks on the job

Studies at the Sleep Institute have also contributed to warnings about the risks that sleep disturbances may bring to the workplace. One study, conducted by Marco Túlio de Mello, associate professor in the Department of Psychobiology at UNIFESP and researcher at the Sleep Institute, and Sergio Tufik, principal investigator at the Institute, investigated 400 drivers at a large bus company. 

The results revealed that after a period of sleep, 48% of the subjects (that is, nearly half of all the drivers) remained tired and suffered from attention deficits when it was time for them to drive again.

Completion of the study enabled the RIDC to recommend modifications to the companies’ work shifts that drastically reduced the number of accidents and were particularly influential in drafting new traffic legislation [see the detailed description of these studies in the article A study that changed the law].

To learn more: Health and sleep disorders and Hormonal oscillations.