In an article published in the August 15, 2009 issue of Biological Psychiatry, researchers at Yale University and the Veterans Administration National Center for Post Traumatic Stress Disorder report that having a higher level of the hormone dehydroepiandrosterone (DHEA) is associated with an improved ability to cope with extreme stress.
Dr Charles A. Morgan III, of Yale's department of psychiatry and the VA Connecticut Healthcare System and his colleagues evaluated performance and psychological symptoms among 41 healthy special operations soldiers enrolled in the military Combat Diver Qualification Course, which exposes participants to significant stress while engaging in a series of nocturnal underwater navigation exercises over a month-long period. Blood samples obtained prior to and following the course were assessed for plasma DHEA, DHEA sulfate, and the stress-related hormone cortisol.
Dr Morgan's team found that participants who had higher DHEA and DHEA sulfate levels at the beginning of the study performed better than those with low levels. Participants with higher DHEA levels also had less stress-induced symptoms of dissociation while performing.
Dehydroepiandrosterone is secreted by the adrenal glands in response to stress, and has been shown to improve stress response in animals. In humans, the ability to navigate underwater relies on the brain's hippocampus, a region that is very sensitive to stress’s effects. "Animal studies have shown that DHEA buffers against stress, in part, by modulating receptors in this region of the brain," Dr Morgan explained. "These findings are important in understanding why and how soldiers may differ in their ability to tolerate stress and also raise the possibility that, in the future, compounds like DHEA might be used to protect military personnel from the negative impact of operational stress."
"These data provide prospective, empiric evidence that DHEA and DHEAS are associated with superior stress tolerance, fewer symptoms of dissociation, and superior, objectively assessed, military performance," the authors conclude.
Posttraumatic stress disorder (PTSD) is precipitated by experiencing or witnessing a traumatic or terrifying life event, such as a serious accident, a violent crime, or a natural disaster. People with PTSD may relive the event in nightmares or have disturbing recollections of it during waking hours. Ordinary events can trigger flashbacks that may result in a loss of reality, causing the person to believe the event is happening again. Approximately 5.2 million Americans are affected by PTSD, which can occur at any age (Narrow WE et al 2002; Margolin G et al 2000).
Symptoms associated with PTSD include inability to sleep, hypersensitivity to external stimuli, feelings of detachment or numbness, and loss of memory of the time surrounding the traumatic experience. In addition to the presence of these symptoms, doctors considering a diagnosis of PTSD consider whether a patient persistently re-experiences the traumatic event, such as by recollecting it, dreaming about it, experiencing hallucinations or flashbacks, or physically reacting to internal or external cues that symbolize or resemble an aspect of it. For a diagnosis of PTSD, symptoms must be present for more than one month but may occur years after the traumatic event (American Psychiatric Association 2000).
By now, it is well known that most steroid hormones (e.g., pregnenolone, estrogen, progesterone, testosterone, and DHEA) are neurologically active. In fact, large quantities of DHEA, as well as estrogen and progesterone receptors are found in the brain. These hormones have a number of effects within the brain, including regulation of mood. Accordingly, a number of studies have linked abnormalities in hormone levels to various anxiety disorders (Birzniece V et al 2006; Cohen H et al 2006; Strous RD et al 2006). In addition, studies have documented that abnormalities in the hypothalamic-pituitary-adrenal axis, which controls the body’s response to stress through the release of cortisol and DHEA, can predispose a person to anxiety and depression (Leonard BE 2005). During times of stress and anxiety, the balance between cortisol and DHEA is altered in favor of cortisol.
Well before coronary heart disease itself gets underway, so-called risk factors for heart disease declare themselves. Atherosclerotic plaque initiates and grows for good reason. Risk factors identify some of those reasons.
This is the role of risk factors: To provide an indication that potential for atherosclerosis is present.
If you’ve become a bit confused about this conversation over the past few years, you are not alone. Controversy over the importance of risk factors, the overselling of cholesterol drugs, and the emergence of newly identified risk factors for heart disease has made this a rapidly changing, and often difficult to follow, discussion.
The understanding of risk factors for heart disease has come a long way since the 1940s, when it was not at all clear just what aspects of diet, lifestyle, or genetics lay behind the disease. Even cigarette smoking was still being advertised as a healthy habit: “Camels: Smoked by more doctors than any other brand!”
But, even after nearly 60 years of research and heated debate, there is not uniform agreement on what causes heart disease. We’ve zigzagged around the role of diet, cholesterol, and fats, while newly appreciated phenomena like inflammation, genetic factors, and vitamin D deficiency emerge and even further transform the discussion.
We might regard it as 60 years of confusion—or 60 years of wisdom gained. Despite the controversies and persistent uncertainties, surely there are some nuggets of wisdom to be learned.
Creatine exerts various effects upon entering the muscle. It is these effects that elicit improvements in exercise performance and may be responsible for the improvements of muscle function and energy metabolism seen under certain conditions. Several mechanisms have been proposed to explain the increased exercise performance seen after creatine intake.
Optimizing energy metabolism by maintaining higher levels of the body’s energy compound adenosine triphosphate or ATP
Increasing myofibrillar mRNA content and protein synthesis, and reducing amino acid oxidation and protein breakdown
Increasing satellite cell and myonuclei number and activity in human skeletal muscle
Preventing tissue damage by stabilizing cellular membranes and maintaining reserves of ATP
Wouldn't you like to know how to prevent your body from aging badly? The original YOU book showed how bodies work in general, and YOU: On a Diet explained how bodies lose weight and stay fit. Now in YOU: Staying Young, Drs. Michael Roizen and Mehmet Oz illuminate the mysterious mechanisms with a lively metaphor -- the modern city. What differentiates a vibrant and thriving city that ages gracefully from one that is worn down and rusted out? Despite genetic differences, which are like the geography upon which the city is built, cities age differently because of the way residents treat their education system (stem cells), power plants (mitochondria), electrical grids (brains), transportation routes (blood vessels), and landfills (fat). You -- as mayor, resident, and street cleaner -- have the power to balance your biological budget to ensure a life that's both long and strong. Thankfully, just as cities can invest in renewal and improving their repair processes, so can you.