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New research has uncovered a connection between how older adults feel on Mondays and their long-term biological stress levels. The study found that people aged 50 and over who reported feeling anxious on a Monday had significantly higher levels of stress-related hormones in their bodies up to two months later. This effect was not limited to those still in the workforce, suggesting that Monday-related anxiety may be deeply ingrained and could contribute to long-term health problems, including cardiovascular disease.
The study was led by Tarani Chandola from the University of Hong Kong and published in the Journal of Affective Disorders. It was the first of its kind to show that the psychological experience of Monday anxiety has a measurable effect on the body’s stress regulation system over time. These findings offer insight into why heart attacks and other cardiovascular events are more common on Mondays, a phenomenon that has puzzled scientists for decades.
The research team set out to explore why Mondays appear to be linked to worse health outcomes. Previous studies have shown a rise in heart attacks, strokes, and even suicides at the beginning of the week. Some researchers have proposed that the transition from the weekend to the start of the workweek triggers stress and anxiety, which could strain the body’s systems. However, until now, there was limited evidence connecting this idea to biological changes in stress hormones that last beyond the immediate moment.
“I have been working on the topic of cortisol responses to work related stressors for a long time and there is a well-established diurnal rhythm to our cortisol stress response. I wanted to see whether there was a similar pattern to our weekday/weekend stressors,” Chandola, a professor of medical sociology.
To investigate this possibility, the researchers used data from the English Longitudinal Study of Ageing, a large, ongoing project that collects health and lifestyle information from adults aged 50 and older in England. The sample included over 3,500 individuals who had completed both psychological surveys and provided biological samples.
Participants were asked how anxious they felt the day before, rating their experience on a scale from 0 (not at all anxious) to 10 (very anxious). They also indicated which day of the week they were referring to. For the purposes of analysis, the researchers grouped responses into “low” (scores 0–3) and “high” (scores 4–10) anxiety.
In a separate part of the study, trained nurses collected small samples of hair from each participant’s scalp. These samples, measuring about 2 to 3 centimeters, reflect hormone levels accumulated over the previous two to three months. This method allowed the researchers to measure long-term levels of cortisol and cortisone—two hormones produced by the body in response to stress.
Cortisol is often called the “stress hormone” because it plays a major role in the body’s response to psychological pressure. When stress becomes chronic, the body can either produce too much or too little of it, leading to problems in heart health, metabolism, and immune function. By looking at hormone levels in hair, rather than blood or saliva, the researchers were able to get a more stable picture of biological stress over time, rather than just at one moment.
The study found a clear pattern. Older adults who reported feeling anxious on a Monday had significantly higher levels of cortisol in their hair samples than those who reported feeling anxious on other days of the week. This difference was most pronounced among those with the highest cortisol levels. For people in the top 10 percent of the cortisol distribution, those who felt anxious on Mondays had hormone levels that were about 23 percent higher than their peers who felt anxious on other days.
This pattern held true even after the researchers accounted for a wide range of other factors that could influence stress hormone levels, including age, sex, education, relationship status, smoking, hair type, season, and whether the participant was still employed. They also examined whether people who were still working were more affected by Monday anxiety than retirees, but they found no meaningful difference between the two groups. This suggests that Monday-related stress may not be solely about returning to a job, but may reflect a broader psychological association with the start of the week.
“I thought that the retired people would no longer show this pattern of higher cortisol levels correlated with feelings of anxiety on Mondays. The fact that this persisted suggests that the biological consequences of feelings of anxiety on Monday over the life-course do not go away when people retire.”
To better understand the results, the researchers used a statistical method called decomposition analysis. This allowed them to separate the part of the Monday effect that could be explained by known variables—such as higher reported anxiety levels on Mondays—from the part that remained unexplained. They found that about three-quarters of the difference in cortisol levels could not be explained by the measured variables, meaning there may be other factors at play, such as individual sensitivity to weekday routines or long-standing emotional patterns tied to Mondays.
Notably, the link between anxiety and higher cortisol levels was not seen on any other day of the week. People who felt anxious on, say, a Wednesday or Friday did not show the same long-term increase in stress hormone levels as those who felt anxious on a Monday. This highlights the unique psychological weight that Mondays seem to carry for many people, regardless of their day-to-day responsibilities.
“Feeling anxious on Mondays is correlated with long term biological stress responses. The good news is that those feelings of anxiety are not correlated with stress responses on other days of the week, particularly the weekends. This suggest the importance of weekends for rest and recuperation.”
But there are some limitations to consider. The study was observational, which means it cannot prove that feeling anxious on Mondays causes higher stress hormone levels. The data relied on a single measure of anxiety and a single collection of hair samples, so changes in hormone levels over time within the same individual were not tracked. There is also some uncertainty around the exact time period captured by each hair sample, as hair growth rates can vary slightly between people.
Despite these caveats, the researchers argue that the results point to a biological basis for what many people casually refer to as the “Monday blues.” The fact that this effect shows up in long-term hormone patterns suggests it is not just a passing mood, but something that may have lasting implications for health.
The study contributes to a larger body of research on how psychological stress interacts with the body’s systems. It also raises new questions about why some people are more affected by the start of the week than others, and why some never seem to adapt to it—even after leaving the workforce.
Future research will explore what makes certain people resilient to Monday-related anxiety. The researchers hope to investigate what types of routines, personality traits, or coping strategies might protect people from these stress patterns. Understanding these factors could lead to interventions that help people better manage anxiety, particularly at vulnerable times like the beginning of the week.
“Feelings of anxiety could be tied in with stressors related to work or school at the start of the week. I would like to examine what makes some people not feel anxious at the start of the week, as well as the factors that enable some people to be resilient to Monday stress. This research is part of a long line of research on the physiological consequences of work-related stress. It is important to remember that stress is not just a feeling or emotion, but has biological and physiological consequences.”
The study, “Are anxious Mondays associated with HPA-axis dysregulation? A longitudinal study of older adults in England,” was authored by Tarani Chandola, Wanying Ling, and Patrick Rouxel.