Untangling the Links Between Sedentary Behavior and Depression

Among the detrimental effects that are increasingly being blamed on sedentary behavior are mental health conditions such as depression. In one study I wrote about a couple years ago, researchers found that just one week of sedentary behavior could significantly lower people’s life satisfaction.

Figuring out why sedentary behavior and depression go together is more difficult – not because it’s hard to think of ways they might be related, but because there are so many ways they might be related that it quickly gets complicated trying to suss out which are most important!

A new study published in Journal of Affective Disorders sheds some light on the matter. In an experiment focused on adults over the age of 50, researchers examined a range of possible factors linking sedentary behavior and depression.

Consistent with previous studies, the researchers found that older adults who reported higher levels of sedentary behavior also had more symptoms of depression.

However, that didn’t mean that sedentary behavior was the cause of those depressive symptoms. In fact, the researchers found that several other factors explained most of the link between sedentary behavior and depression.

These included people’s social network and levels of loneliness. Being less socially connected was associated both with more sedentary behavior and with depression, and social network and loneliness together explained about 35 percent of the link between sedentary behavior and depression.

Chronic physical conditions and disability were also important. This makes sense because health problems could simultaneously increase both levels of sedentary behavior and depression, but in that case it’s not the sedentary behavior that’s causing the depression.

Finally, about 20 percent of the link between sedentary behavior and depression had to do with physical activity – which was assessed as whether people met the guidelines of either 150 minutes of moderate or 75 minutes of vigorous physical activity weekly. The implication of this finding is that, to some extent, a lack of physical activity specifically rather than sedentary behavior generally might be the culprit in lower mental health.

The takeaway from these findings isn’t that high levels of sedentary aren’t something to be concerned about. After all, this study only looked at one measure of mental health and didn’t get into the physical health effects of sedentary behavior.

What the results do suggest is that if the goal is to lower depression risk, interventions designed to lower sedentary behavior might be more effective if they specifically target some of the areas of life that link sedentary behavior and depression: building social connections, meeting physical activity guidelines, and coping with physical health conditions.