The most recent survey of stress in America indicates that women continue to bear the heavier burden of stress, particularly due to financial concerns and worries over their family’s health and family responsibilities. Women consistently report more physical and emotional stress than men, and are more likely to lack the willpower to make changes recommended by health care providers, the survey results also show. What is causing this unhealthy gender bias? Allostasis, or more precisely allostatic load, is the key to understanding gender differences in stress. Let’s first understand allostasis, its benefits, and potential dangers.
Allostasis: Too Much of a Good Thing
Allostasis defines the processes that attempt to maintain the body’s internal stability in the face of physical or psychological challenges. Physiological and behavioral changes are initiated automatically during the stress reaction to external environmental and developmental threats, such as danger, conflict, financial worries, interpersonal difficulties, family and job demands, and other life stressors. Allostasis as a process is a very good thing and aids in survival and coping. It can work well at restoring the body’s equilibrium and ensure an adequate response to the threat. However, allostatic processes can cause physical and psychological damage when they extend beyond their intended short-term activation. This prolonged state of activation creates a burden on the system, known as the allostatic load.
Four factors can contribute to the formation of a heavy allostatic load:
- Repeated physical or psychological challenges (e.g., prolonged financial stress, a stressful job, multiple and conflicting demands of time and resources, a serious illness, childhood trauma, adult abuse or violence)
- Inability to adapt to these repeated challenges (the feeling of being at the end of one’s rope)
- Inability to produce an adequate response to the stressor (such as the phenomenon of learned helplessness, depression or anxiety)
- Inability to end the stress reaction even after the stressor has been removed (chronic stress)
Allostatic load accumulates over time. The continuation of multiple small changes in physiological and psychological functioning (which are meant to be only short-term), due to a persisting state of alert against perceived threats (the classic stress syndrome), creates the potential for illness.
What Happens to the Body During Allostasis
During the normal stress response and the body’s process of allostasis, the stress hormones serum dehydroepiandrosterone (DHEA), cortisol, norepinephrine and epinephrine are secreted into the blood stream. The immune system and neurological responses are activated, along with muscular, cardiovascular and pulmonary system. Alongside these physical reactions, psychological changes take place in response to anxious, fearful, hostile or aggressive states produced by the stressor. Behavioral changes also occur in trying to cope with the stressor, sometimes consisting of alcohol abuse and other substances, working too many hours, or exercising compulsively. Sleep disturbances, depression and other psychological symptoms are usually the first evidence of an increasing allostatic load.
At the physiological level, allostatic load can cause atrophy of the hippocampus and structural changes in the amygdala and the prefrontal cortex, resulting in a more or less severe impairment in spatial learning and memory. Certain tell-tale physical responses are also indicative of a heavier allostatic load: higher blood pressure, changes in waist-hip ratio, higher serum high-density lipoproteins (HDL) and cholesterol, and glycosylated hemoglobin levels.
These psychophysical changes, though helpful in the short run, can cause damage. This damage is the cost of maintaining an allostatic state longer than is optimal for health. Numerous studies of allostasis show the risk of stress-induced illnesses such as cardiovascular disease, atherosclerosis, metabolic syndrome, Type 2 diabetes, depression, anxiety, and immune/auto-immune disorders.
What about the effects of allostatic load on women? Details after the jump.
The Gender Bias in Allostatic Load
Gender appears to be a significant factor in allostatic load. Males and females in humans and in most animal species differ in neuroanatomy, stress axes, neuroendocrinology, and immunology, and these differences affect the rate of accumulation and the severity of the allostatic load. Allostatic load differences produce higher gender-specific risks for diseases, such as depression (twice as frequent in women than men) and autoimmunity for women, and cardiovascular disease and suicide for men.
Why is this happening? A key factor is the way women perceive and evaluate stress. Potential stressors are evaluated as they occur as being either innocuous, dangerous, or challenging. This perception causes the stress reaction to be initiated.
In women, the stress reaction causes the release of stress hormones but also of higher levels of oxytocin, the hormone that regulates milk ejection and uterine contractions. Oxytocin influences behavior, stress reactivity, cardiovascular and nervous system functioning, endocrine responses, and immune function. Oxytocin is also responsible for the instinctive and typical female reaction to a dangerous or stressful situation.
For clues of what may be typical for women, we can look at female behavior in reaction to a stressor among most animal species. Unlike males, it is not typical of females to leave the nest and fight an aggressor, putting both the mother and offspring in greater danger. Fleeing is also not a good option for the offspring’s survival. Females, which are generally smaller and weaker, are at a greater disadvantage than males when put into predator-prey situations. The safer and more typical response to stress for females is to tend and befriend. Tending puts the well-being of the offspring as a first priority, and befriending seeks social affiliation (usually with other females), so that group members have a better chance of protecting each other’s offspring. Even though the similarities among females of various animal species may be coincidental, it appears that the tending and befriending instinct is biologically innate and, from a survival perspective, absolutely essential.
The End Result Is the Beginning of a Stress Crisis
Today, most American women (65%) work and no longer stay at home with their families. Changing lifestyle choices and economic pressures continue to push more women to work. Career demands compete with time spent with children. Adding more stress is the fact that 40% of American women work in low-paying jobs with unpredictable work schedules, meager benefits, and little opportunity for advancement. Oxytocin, allostasis and chronic stress do the rest.