The long-term effects of stress

People whose negative emotional responses to stress carry over to the following day are more likely to report health problems and physical limitations later in life compared with peers who are able to 'let it go', according to findings published in Psychological Science.

"Our research shows that negative emotions that linger after even minor, daily stressors have important implications for our long-term physical health," says the lead researcher.

"When most people think of the types of stressors that impact health, they think of the big things, major life events that severely impact their lives, such as the death of a loved one or getting divorced," she says. "But accumulating findings suggest that it's not just the big events, but minor, everyday stressors that can impact our health as well."

Evidence from previous studies suggests a clear association between same-day responses to stress and long-term wellbeing, but the impact of lingering emotional responses remained unclear. That is, does it make a difference if a stressor — such as a flat tire, a bad grade, or an argument — leads to negative emotions that spill over into the following day?

To find out, the researchers analysed data from the Midlife in the United States Survey, a nationally representative, longitudinal study of adults.

As part of the study, participants completed an eight-day survey of negative emotion; each day, they reported how much of the time over the previous 24 hours they had felt a variety of emotions (e.g., lonely, afraid, irritable and angry). They also reported the stressors that they experienced each day.

In a subsequent part of the study that took place 10 years later, the participants completed surveys that assessed their chronic illnesses and functional limitations. Participants reported the degree to which they were able to carry out basic and everyday tasks, such as dressing themselves, climbing a flight of stairs, carrying groceries, and walking several blocks.

As expected, people tended to report higher negative emotion if they had experienced a stressor the previous day compared with if they hadn't experienced any stressor the day before.

Critically, analyses revealed that lingering negative emotions in response to a stressor were associated with a greater number of health problems, including chronic illnesses, functional impairments, and difficulties with everyday tasks, a decade later.

These associations emerged independently of participants' gender, education and baseline health, and they held even after the researchers took participants' same-day emotional responses and average number of stressors into account.

"This means that health outcomes don't just reflect how people react to daily stressors, or the number of stressors they are exposed to — there is something unique about how negative they feel the next day that has important consequences for physical health," explains the lead researcher.

The researchers hypothesise that this link could play out through activation of stress-related systems or through health behaviours, two potential mechanisms that offer avenues for future research.

"Stress is common in our everyday lives. It happens at work, it happens at school, it happens at home and in our relationships," say the researchers. "Our research shows that the strategy to 'just let it go' could be beneficial to our long-term physical health."

So what?

Our physical and mental health are very closely linked to our stress level. Previous research has shown how undue stress can lead to cardiac problems up to two generations later. Being fired more than twice can lead to a heart attack up to two decades or more later. Ditto divorce.

Now this research shows that it is not just the big things — it is the "ordinary" modern-day stressors, the kind that our ancestors didn't have to face and therefore weren't factored into our genome, which can also be the killers. This is really important information.

What now?

In every way, we are finding out that we need to take human neurogenetic design specs into consideration when organising our lives and the lives of others. Just "letting go" is useless advice when our modern life styles are so out of step with our genetics that our systems are incapable of dealing with even the most "trivial" of stressors.

Resilience requires our being surrounded by a network of supportive face-to-face relationships. That's the way that our human systems can cope with stress. That's the way we always did.