Stress is something we all experience or have heard others complain about. One could think about stress being related to poor health, struggling finances, strained relationships, or demanding work conditions. Such stress has been linked to higher cortisol levels and the potential risk of heart disease. And yet, stress could also be a motivator for some. Think about the last time you were up against a deadline; perhaps the stress you felt pushed you to finish the task before the deadline.

Intrigued by the dual role of burden and motivation that stress could play under different life conditions, we decided to dig deeper. Our goal was to identify lifestyle factors that influence these two dimensions of stress with increasing income. We drew inspiration from the works of Kahneman and Deaton, Killingsworth, and Jebb et al. to probe the income-stress relationship. Rather than relying on commonly employed linear regression methods, we used non-linear methods to unravel potential non-linearity in the income-stress relationships stemming from different lifestyle factors that contribute to stress at various income levels.  

We found a turning point (U-shaped trend) for the income-stress relationship. In other words, up to a certain income, higher income is associated with lower stress, and after the turning point, higher income is associated with higher stress. This trend is unique compared to other dimensions of well-being, such as life satisfaction or sadness, where we find monotonic trends with income. 

What determines the location of the turning point is even more perplexing. We find that individuals with lifestyle factors that one could reasonably assume to be desirable - such as being healthier, more social, having their basic needs fulfilled, and in general, having higher life satisfaction, have a turning point at a lower income.  Predictably, these life conditions have overall lower stress compared to those without these desirable conditions. But paradoxically, they are also more likely to see their stress levels rise sooner as their incomes grow. It appears that once individuals have quelled stress associated with basic needs, health, and social factors, they become more susceptible to stress at lower income levels.

This brought us to the all-important question: Is an earlier turning point desirable? Unfortunately, this question is difficult to answer with the data we have. Our stress measure is a simple Yes/No question and lacks nuance in the intensity, duration, and desirability of the stress that individuals experience. We do not know if individuals seek such stressful situations (for example, through ambitious goals) or if they inexplicably find themselves in such situations due to their other needs being met. 

There is evidence in the literature that, under certain conditions, moderate stress could be desirable. One possible explanation for the stress after the turning point is the flow state, introduced by Csikszentmihalyi. This idea has also been popularized in the workplace and productivity literature as eustress. Eustress or flow can be understood as a state of mind where the stress levels and your skills are sufficiently matched to help achieve one’s goals.  Of course, what we do not know is whether, under certain conditions, individuals value their productivity/goals arising from such stress over other forms of well-being, like life satisfaction. We do not have all the answers yet. Future research can focus on the nature and intensity of the stress that individuals face, especially after the turning point.

Regardless of the underlying reasons and desirability of stress, our work indicates that there is a transition in the income-stress relationship. Whether there is linearity, satiation, or a turning point in well-being dimensions with increasing income is a long-standing debate. With this work, our goal was to add to this discussion by specifically looking at stress and the underlying heterogeneity that govern these well-being trends.  While we have looked at several underlying lifestyle factors that dictate these trends, the turning point debate is far from over. More complex models combining even more lifestyle factors can bring fresh insights into the intricacies between income, stress, and lifestyle factors. One thing is clear for now: the relationship between income and stress is far from linear.