It’s well established that our moods and behaviors can impact our relationships and the other people in them, but their moods and behaviors can impact us right back, which in turn impacts them, and so on. It’s a vicious cycle.
That’s the conclusion of a new study, which has found evidence that such a cycle may exist between sedentary time and depression in close relationships. When one partner has depressive symptoms, the other increases their sedentary behavior, and when one partner increases their sedentary behavior, the other is more likely to have depressive symptoms.
Previous research into this symbiosis between sedentary time and depression has focused largely on individuals, hinting that the two worsen each other in a cyclical manner.
Although the reason for this link is not yet clear, the researchers hypothesize that an individual’s sedentary behaviors may exacerbate their depressive symptoms by limiting contact with other people and increasing social isolation. On the other hand, high levels of depressive symptoms increase the likelihood of replacing physical activity with more sedentary time, which makes a recurrence of depression more likely, they suggest. They also note a possible biological mechanism, involving heightened inflammatory markers, which could underpin this.
The new study, however, sought to investigate whether this association held true in relationships.
“Our study is among the first to provide evidence for crossover (i.e., from one person to another) effects for sedentary behaviors and depressive symptoms,” the authors write. “The observed indirect effects [provide] partial support for a vicious cycle of sedentary behaviors and depressive symptoms.”
The observations were made in 320 pairs participating in an intervention to reduce sedentary behaviors and increase physical activity as a way of managing chronic illness. In each pair, one person was the focus, while their partner accompanied and supported them through the lifestyle change. All couples had been in a close relationship, largely romantic although some were friends, family members, or workmates, for at least six months.
Their depressive symptoms were assessed using a questionnaire, and sedentary time was measured using accelerometers at three time points.
Over 14 months, some significant crossover effects became clear: the focus person’s depressive symptoms at baseline predicted how sedentary their partner would be at eight months, while the partner’s sedentary time at baseline predicted the focus person’s depressive symptoms at eight months. This then predicted the partner’s sedentary time at 14 months.
To put it more simply, when the partner was more sedentary, the focus person had more depressive symptoms, and in turn, the partner was more sedentary.
The researchers controlled for sociodemographic factors, including gender, age, and education, but these did not alter the results.
While they admit that the effects obtained were weak and may not be clinically significant, the authors hope that future research could rectify that. They also highlight several of the study’s limitations, for example, that participants were mostly highly educated with medium or higher economic status, and that the overall levels of depressive symptoms were mild.
Nevertheless, they highlight the potential implications of their findings for improving treatment of depression in people with chronic illness, which should, they suggest, also include partners.
The study is published in Mental Health and Physical Activity.