Sexual and Reproductive Dysfunction
Sexual Function. Stress can lead to diminished sexual desire and an inability to achieve orgasm in women. Stress response can also cause temporary impotence in men. Part of the stress response involves the release of brain chemicals that constrict the smooth muscles of the penis and its arteries. This constriction reduces the blood flow into and increases the blood flow out of the penis, which can prevent erection.
Fertility. Stress may even affect fertility. Stress hormones have an impact on the hypothalamus gland, which produces reproductive hormones. Severely elevated cortisol levels can even shut down menstruation. One interesting small study reported a significantly higher incidence of pregnancy loss in women who experienced both high stress and prolonged menstrual cycles. Another reported that women with stressful jobs had shorter periods than women with low-stress jobs.
Effects on pregnancy. Old wives’ tales about a pregnant woman’s emotions affecting her baby may have some credence. Maternal stress during pregnancy has been linked to a 50% higher risk for Miscarriage. It is also associated with lower birth weights and increased incidence of premature births, both of which are risk factors for infant mortality. One study suggested that stress experienced by expectant mothers can even influence the way in which the baby’s brain and nervous system will react to stressful events. Stress may cause physiologic alterations, such as increased adrenal hormone levels or resistance in the arteries, that may interfere with normal blood flow to the placenta.
Memory, Concentration, and Learning
Stress has significant effects on the brain, particularly on memory. The typical victim of severe stress suffers loss of concentration at work and at home and may become inefficient and accident-prone. In children, the physiologic responses to stress can clearly inhibit learning. Although some memory loss occurs with age, stress may play an even more important role than simple aging in this process. In one study older people with low stress hormone levels tested as well as younger people in cognitive tests: those with higher stress levels tested between 20% and 50% lower.
Effect of Acute Stress on Memory. Studies indicate that the immediate effect of acute stress impairs short-term memory, particularly verbal memory. In one interesting 2000 study, subjects took pills containing either cortisone (a stress hormone) or a placebo (a dummy pill). Those taking the cortisone performed significantly worse on memorization tests than those taking the placebo pill did. In an earlier study, when individuals were subjected to four days of stress, verbal memory was also impaired. Fortunately, in such cases, memory is restored after a period of relaxation.
Effect of Chronic Stress on Memory. Studies have strongly associated prolonged exposure to cortisol (the major stress hormone) to shrinkage in the hippocampus, the center of memory. For example, two studies reported that groups who suffered from Post-traumatic Stress Disorder (Vietnam veterans and women who suffered from sexual abuse) displayed up to 8% shrinkage in the hippocampus. It is not yet known if this shrinkage is reversible.
Revision date: July 8, 2011
Last revised: by Jorge P. Ribeiro, MD