While everyone knows stress is bad, researchers have now found that simply expecting to be stressful can lower cognitive abilities throughout the day.
Their paper is published in the Journals of Gerontology: Psychological Sciences.
Stress and working memory
Many studies have already shown how stressful events can affect not only our emotion and physiology, but also cognitive abilities.
However, researchers at Penn State University wondered if simply anticipating stressful events that haven’t yet happened would lower working memory, an important cognitive function that works like mental sticky notes and helps us retain information until we need to use it.
“Humans can think about and anticipate things before they happen, which can help us prepare for and even prevent certain events,” Jinshil Hyun, a doctoral student in human development and family studies at Penn State, said in a statement. “But this study suggests that this ability can also be harmful to your daily memory function, independent of whether the stressful events actually happen or not.”
The problem is that our working memory capacity is limited — it steadily rises and falls in a shape of an arc as we age, reaching its peak in young adulthood and gradually declining in old age.
While it is normal for working memory to gradually decline, severely reduced working memory can cause mental illnesses, such as schizophrenia, depression and alzheimer’s disease.
Also, even in childhood, if working memory does not properly develop, it can cause difficulties in attention, reading and language.
“A reduced working memory can make you more likely to make a mistake at work or maybe less able to focus,” Martin Sliwinski, director of Penn State’s Center for Healthy Aging, said in a statement. “Also, looking at this research in the context of healthy aging, there are certain high stakes cognitive errors that older adults can make. Taking the wrong pill or making a mistake while driving can all have catastrophic impacts.”
The study
The researchers recruited 240 racially and economically diverse adults to participate in a study conducted via smartphones throughout their daily lives.
For two weeks, the participants responded seven times a day to questions prompted from a smartphone app: once in the morning about whether they expected their day to be stressful, five times throughout the day about current stress levels, and once at night about whether they expected the following day to be stressful.
“Having the participants log their stress and cognition as they went about their day let us get a snapshot of how these processes work in the context of real, everyday life,” Hyun said in a statement. “We were able to gather data throughout the day over a longer period of time, instead of just a few points in time in a lab.”
According to Sliwinski, the researchers motivated the participants to answer honestly on their own by assuring them that their data were de-identified, meaning their answers cannot be linked back to them, and providing financial compensation for the time taken to participate in the study.
The participants also completed a working memory task that measured spatial working memory five times a day.
“They had 3 seconds to study the locations of 3 dots randomly placed on a 5-by-5 grid. After that brief study period, they had to perform a visual distraction task for 8 seconds, and then recall where the dots were located,” said Sliwinski. “Their performance was scored based on how closely the locations they recalled aligned with the original location of the dots.”
The result
The researchers found that when participants woke up expecting the day to be stressful, their working memory was lower later in the day.
Also, the more stress participants anticipated in the morning, the lower was their working memory later in the day.
Interestingly, stress anticipation from the previous evening was not associated with lower working memory.
Sliwinski said the findings show the importance of a person’s mindset first thing in the morning, before anything stressful has happened yet.
“When you wake up in the morning with a certain outlook for the day, in some sense the die is already cast,” he said in a statement. “If you think your day is going to be stressful, you’re going to feel those effects even if nothing stressful ends up happening. That hadn’t really been shown in the research until now, and it shows the impact of how we think about the world.”
But the researchers understand that stressful things will happen in life.
So for the next time you wake up thinking a stressful day is ahead of you, they encourage setting for yourself possible interventions that can help you be aware that your cognitive abilities may not be optimal.
“If you wake up and feel like the day is going to be stressful, maybe your phone can remind you to do some deep breathing relaxation before you start your day,” Sliwinski said in a statement. “Or if your cognition is at a place where you might make a mistake, maybe you can get a message that says now might not be the best time to go for a drive.”
The next step
The researchers are currently using the similar methods using smartphones to understand long-term effects.
“We are using these methods for ambulatory assessment using mobile technology to improve our understanding of how everyday experiences and behaviors impact cognitive function over the long-term,” said Sliwinski. “For example, we are using a similar protocol in older adults (aged 70+) to identify modifiable risk factors for Alzheimer’s and related dementias that we hope will improve early detection and prevention efforts.”
In the near future, they plan on running additional studies using wearable sensors to gather even more in-depth data on the effect of stress on participants’ physiological states.According to Sliwinski, in a separate project, the study’s co-author Joshua Smyth, who is a professor of biobehavioral health and medicine at Penn State, will evaluate novel “just-in-time” interventions delivered by mobile phones to minimize the effects of everyday stress on emotional well-being and health.
