Stress and Cognitive Decline

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Stress and Cognitive Decline

Having a well-functioning memory is something we all think about more and more as we age. Memory and other cognitive processes gradually diminish as we grow older, but research in the last several decades shows those who experience persistent or high levels of stress are especially vulnerable.

Although much remains to be learned about the causes of mental decline, it has been well documented recently that stress is an important contributing factor, including to the development of Alzheimer’s disease and other dementia. A research team in Sweden observed in a recently published 38-year study of 800 women that “psychosocial stressors in midlife were associated with incidence of AD (Alzheimer’s disease) and long-standing distress, over several decades.” The study, conducted at the Sahlgrenska Academy at the University of Gothenburg, concluded “this suggests that common psychosocial stressors may have severe and long-standing physiological and psychological consequences.”

Effects of Stress on Memory and Cognitive Functions

The negative effects of stress on memory and other cognitive functions has been widely explored for decades in numerous research projects using a wide range of methodology.

  • A study out of the Netherlands published in 2007, The effects of cortisol increase on long-term memory retrieval during and after acute psychosocial stress, examined short- and long-term memory.

Students were tasked with retrieving/recalling emotionally negative and neutral word associations in this study, which is referenced by the National Institutes of Health’s National Center for Biotechnology Information website. The 70 male participants learned some of the words one day before the tests and other words five weeks earlier.

“Within the stress condition, retrieval of negative words, 5 weeks after learning, was impaired both during and after the stress task, compared to the control group,” the researchers wrote.

  • A University of California, Irvine study, Mechanisms of late-onset cognitive decline after early-life stress, correlated memory dysfunction in young adult rats that experienced “early-life psychological stress” with humans. “These findings constitute the first evidence that a short period of stress early in life can lead to delayed, progressive impairments of synaptic and behavioral measures of hippocampal function, with potential implications to the basis of age-related cognitive disorders in humans.”

  • In another study, cited by Prevention magazine, German scientists conducted two separate experiments in which 60 participants were subjected to mild forms of emotional and situational stress. The results showed that “women who were stressed took 10% more time to recall recently learned information.” The reason, the article explained, is because the hormones, cortisol, often referred to as the stress hormone, and noradrenalin, flooded the prefrontal cortex of the brain, which controls working memory, where new information is processed and retained.

“Our ability to focus, concentrate and remember has a lot to do with how much emotional stress we are experiencing,” write the authors of the book, HeartMath Brain Fitness Program, newly released. “Emotional stress has a major impact on our immediate and long-term cognitive functions, and underlies many of the mental health problems in society today.

Keeping Your Brain Fit with Positive Emotions and HeartMath Techniques

Even as research has intensified recently on how and why cognitive abilities, especially memory, deteriorate with age, so too has the quest to preserve these vital processes for as much of our lives as possible. While various drug therapies provide varying degrees of success, an increasing number of people, including health professionals, are turning to nondrug interventions that have proved to be a more desirable alternative.

With stress identified as a primary contributor to memory and other cognitive impairment and low heart coherence, reducing and controlling unhealthy stress levels is a major focus of many research organizations, among them HMI.

Positive Emotions

HMI’s intense focus on optimal function research since its founding more than two decades ago led its researchers to make an important discovery: Intentionally invoking positive emotions is one of the fastest and most effective ways to reduce unhealthy stress.

“Research has shown that sustained positive emotions lead to a highly efficient and regenerative functional mode associated with increased coherence in heart-rhythm patterns and greater synchronization and harmony among physiological systems,” HeartMath Institute Director of Research Dr. Rollin McCraty writes in his paper, Heart Rhythm Coherence – An Emerging Area of Biofeedback.

One of the most powerful and effective of the positive emotions is appreciation, HeartMath researchers found. Heart-monitoring technology such as an electrocardiogram or HeartMath's emWave Pro (Desktop) to measure heart-rhythm patterns typically displays a nearly instant transformation from erratic to smooth patterns when a subject intentionally experiences appreciation. Smooth heart-rhythm patterns indicate lower stress and greater heart coherence and thus a range of psychophysiological benefits that include improved memory, focus and immune system among many others.

HMI researchers have conducted many trials in which participants realized significant reductions in stress levels and improvements in cognitive functions by intentionally feeling other positive emotions such as care, compassion and love.

How Stress Affects Heart Coherence

When we are angry, frustrated, anxious, depressed or feel other negative emotions frequently and for long periods it is likely we are experiencing unhealthy levels of stress, which adversely affect heart coherence.

“Coherence,” HeartMath Institute Director of Research Dr. Rollin McCraty has written, “is the state when the heart, mind and emotions are in energetic alignment and cooperation. It is a state that builds resiliency – personal energy is accumulated, not wasted – leaving more energy to manifest intentions and harmonious outcomes.”

Negative emotions like those noted above can cause our heart-rhythm patterns to become erratic. These erratic patterns affect our mental processes, including blocking our ability to think clearly. They are sent to emotional centers in the brain, which recognizes them as negative, or stressful feelings.

Learn more about appreciation in the article, An Appreciative Heart Is Good Medicine. Interested in knowing more about positive emotions and the science behind HeartMath?

HeartMath Techniques

In tandem with its research into the effects of stress on emotions, HeartMath has developed and continues work on a variety of tools to help people reduce stress. Hundreds of thousands of people have used these tools, among which are the Neutral, Quick Coherence®, Heart Lock-In® and Freeze Frame® Techniques, and the emWave® technology.

All of these tools, which you can learn more about at free resources, are designed to reduce stress by raising heart coherence. HMI researchers have found this to be highly effective, even in the moment, at restoring both a physical and psychological sense of balance and calm, much like meditation, which HeartMath also highly recommends.

HeartMath’s tools have been used in multiple measures studies to quantify their effectiveness among various groups of people, including students in the federally supported TestEdge® National Demonstration Study.

Results of the study, in which students participated in a program to learn HeartMath techniques, showed substantial reductions in the key stress symptoms students were experiencing, including feelings of loneliness, sadness, anger, depression, and disappointment. Significantly, “of the students who suffered test anxiety (a primary focus of the study), 75% had reduced anxiety by the end of the program.”

Alzheimer’s, Stress and the Decline in Memory and Other Brain Functions

Deterioration of memory and other brain functions are hallmarks of Alzheimer’s disease, which, according to the Alzheimer’s Association, affected an estimated 5.2 million people in the United States in 2013. The figure includes about 5 million people 65 or older and 200,000 under 65 who have what is called “younger-onset Alzheimer’s.”

Whereas short-term stress, which raises cortisol levels for short periods, can be beneficial, long-term stress can lead to prolonged increases in cortisol, which can be toxic to the brain. Scientists suspect high levels of cortisol, the so-called stress hormone, over long periods are key contributors to Alzheimer’s and other forms of dementia, which severely impair short-term memory and other cognitive functions.

While today it is common to know or know of someone with Alzheimer’s, it may be the norm in the future. In just five years, the Alzheimer’s Association predicts, there will a 40 percent increase in the number of people 65 or older afflicted with the disease and nearly a 300 percent increase by 2050, providing there is no breakthrough in treatment to slow or cure it.

HeartMath Institute President Sara Childre is among the many people who have been touched by a disease the Alzheimer’s Association says “is the only cause of death among the top 10 in America without a way to prevent it, cure it or even slow its progression.”

“My father had Alzheimer’s for eight years,” Childre said. “It is a tough disease. He was quite brilliant, had an economics degree and was a three-star general in the Marines. It was so disheartening to see his cognitive functions just melt away. I do believe all the stressors of wars – WWII, the Korean War and two tours in Vietnam – added to the severity of the disease.”

Meditate More

While research to understand, alleviate and cure Alzheimer’s and other forms of dementia and cognitive impairment has intensified in the last decade, great strides have been made toward interventions that focus on reducing stress without drugs. Along with the kinds of positive emotion-based techniques HeartMath has been developing since the early 1990s, is a heart focused meditation.

“Meditation has been shown to have positive effects on the brain and can help reverse memory loss as well as help improve psychological and spiritual well-being, which are both important for healthy brain aging,” explains the HeartMath Brain Fitness Program. The book is co-authored by McCraty and Deborah Rozman, Ph.D., president and CEO of HeartMath Inc.

A team of researchers at Beth Israel Deaconess Medical Center explored whether meditation could prove to be a viable intervention for halting the progression toward dementia in people diagnosed with mild cognitive impairment (MCI). “We wanted to know if stress reduction through meditation might improve cognitive reserve,” said Rebecca Erwin Wells, MD, MPH, who led the team.

Following the trials, the basis of which was a program utilizing meditation and mindfulness – nonjudgmental awareness in each moment – the researchers observed positive results in adult participants with mild cognitive impairment. "These preliminary results indicate that in adults with MCI, MBSR (mindfulness-based stress reduction) may have a positive impact on the regions of the brain most related to MCI and AD (Alzheimer’s disease," they stated in the study’s abstract.

Do you feel stress can accelerate memory decline and meditation can help slow down Alzheimer’s disease?