How Stress Impacts Your Cognitive Reserve and Dementia Risk

Stress can undermine lifestyle factors known to improve cognition in people with Alzheimer’s disease and other forms of dementia, according to new research.

A study published in the journal Alzheimer’s & Dementia by researchers from the Karolinska Institute in Sweden reveals that the cognitive benefits associated with stimulating and rewarding life experiences can be reduced by both physiological and psychological stress.

“These results might have clinical implications as an expanding body of research suggests that mindfulness exercises and meditation may reduce cortisol levels and improve cognition,” said Dr. Manasa Shanta Yerramalla, a lead author of the study and a postdoctoral researcher at the Karolinska Institute’s Department of Neurobiology, Care Sciences and Society. “Different stress management strategies could be a good complement to existing lifestyle interventions in Alzheimer’s prevention.”

Previous studies have shown that a strong cognitive reserve index (CRI) appears to offer protective benefits against cognitive decline in people with Alzheimer’s disease. These CRI scores are calculated based on cognitively stimulating and enriching life experiences, including higher educational attainment, complex jobs, continued physical and leisure activities, and healthy social interactions.

Study Details: Stress and Cognitive Decline

In this new research, the relationship among CRI scores, cognition, and biomarkers for Alzheimer’s disease was examined in 113 participants from the memory clinic at the Karolinska University Hospital. Researchers also assessed levels of perceived stress and biomarkers for psychological stress, specifically cortisol levels in saliva.

The study found that while higher CRI scores were associated with better cognition, adjusting for cortisol levels diminished this beneficial association. Higher CRI scores were linked to better working memory in individuals with healthier cortisol levels but not in those with elevated cortisol levels indicating high psychological stress.

Dr. Logan DuBose, a resident physician at George Washington University and chief operating officer at the elder-care company Olera, commented on the findings: “Chronic stress, which can be caused by a variety of factors including caregiving responsibilities, can lead to elevated cortisol levels. This can damage the hippocampus — the center of the brain associated with memory formation — and negate the benefits of cognitive reserve and neuroplasticity, potentially worsening dementia symptoms.”

Meditation and Mindfulness as Stress Reducers

Engaging in complex occupations, such as being a pilot, medical professional, or financial analyst, can help build cognitive reserve, noted Irv Seldin, CEO of the eldercare company Visiting Angels. However, the persistent stress from these professions can also lead to increased cortisol levels, potentially raising the risk of dementia.

Angela Morrell, a speech-language pathologist at Georgetown University Hospital, emphasized the importance of mentally stimulating activities. “Engaging in mentally stimulating activities can help strengthen neural pathways and improve memory, problem-solving, and communication skills in people with cognitive decline,” she said. “For example, language-based activities like storytelling, word games, or discussions on current events can be great tools for memory clinic patients.”

Morrell, who was not involved in the study, added: “The impact of stress on cognition is important to consider. Chronic stress can negatively affect memory and communication in people with dementia. As speech-language pathologists, we often incorporate stress management techniques into our therapy plans, such as relaxation exercises or mindfulness practices. Understanding how best to manage stress alongside cognitive stimulation programs would be valuable in creating personalized treatment plans aimed at improving the quality of life for people with dementia.”

The study acknowledged its limitations, including a small sample size and the lack of thorough control for sleep impairment, which is known to affect cognition, apart from checking whether participants used sleep medications.