A recent study published in Mental health and physical activity provides new insights into how depression and physical activity influence each other throughout adulthood. The study found that people who feel more depressed are less likely to be physically active, and that being physically active is linked to feeling better mentally. Additionally, results indicate that symptoms of depression may have a negative impact on future physical activity levels.
Depression and lack of physical activity are major public health problems, contributing to disease and reduced quality of life globally. Previous research has suggested a link between the two, but many studies have been unable to determine whether depression leads to a decrease in physical activity or whether physical inactivity exacerbates depression symptoms. The study aimed to fill this gap by using advanced statistical methods to better understand how these factors influence each other over time.
“Symptoms of depression and physical inactivity are quite common and strongly shape the way people perceive themselves and interact with the world. I was attracted to this topic once I learned that physical activity has a similar effect on depression as many antidepressant medications, but without the side effects,” said the study author. Soli Dubash, doctoral student in the department of sociology at the University of Toronto.
The study used data from the Americans’ Changing Lives (ACL) survey, a long-term panel study that followed 3,499 American adults over 25 years, from 1986 to 2011. Participants were surveyed five times at during this period. The sample was diverse, including individuals from various racial backgrounds and both genders, ensuring that the results were representative of the general U.S. population.
Depression symptoms were measured using an 11-item scale from the Center for Epidemiologic Studies Depression Scale. Participants rated how often they experienced symptoms such as feeling depressed, restless sleep, and low energy over the past week. Physical activity was assessed using questions about how often participants engaged in activities such as walking, gardening, and playing sports.
The study used a statistical method known as structural equation modeling with maximum likelihood estimation. This approach allowed Dubash to control for various confounding factors that could influence both depression and physical activity, such as individual biology, life history, and social context.
Dubash found an inverse relationship between depression symptoms and physical activity at each measurement point. This means that people who reported higher levels of depression were less likely to engage in physical activity during the same period, and those who were more physically active tended to report fewer symptoms of depression.
Importantly, the researcher also found that higher levels of depression symptoms predicted lower levels of physical activity in subsequent survey waves. This prospective relationship indicates that people with more severe depression symptoms tend to become less active over time.
Interestingly, the opposite was not observed: physical activity levels did not significantly predict future changes in depression symptoms. This suggests that while physical activity may help maintain mental health, it may not be enough to prevent the onset or worsening of depression over time without directly addressing underlying mental health issues. underlying.
“It was surprising to find that current symptoms of depression can have a negative impact on your physical activity level two to five years later, while being inactive today is not linked to your future symptoms of depression. depression,” Dubash said.
Previous levels of physical activity and depression symptoms were found to significantly predict future levels of those same symptoms. That is, if a person was physically active in previous waves of the survey, they were more likely to remain active in subsequent waves. Similarly, people who experienced higher levels of depressive symptoms in previous waves tended to continue to experience high levels of these symptoms in subsequent waves.
This finding is important because it highlights the persistent nature of physical activity levels and depression symptoms. This suggests that behaviors and mental health states established earlier in life may have long-term effects.
“There are two main conclusions that a normal person should take away from my study,” Dubash told PsyPost. “First, the benefits of moving more (or less) can be felt from week to week. This means that feeling depressed is not a sign that something is wrong with you personally, but rather a sign that you need to move more, no matter what that looks like, whether it’s walking, gardening, or while exercising.
“Second, there’s no bad time to start moving more. Thinking in the medium term, between two and five years, physical activity and depression can be persistent. So, establishing routines for walking your dog or going to the gym with a friend and then sticking to them can have long-lasting benefits for your mental and physical health.
But as with any research, the study comes with some caveats. Measurement of physical activity was based on self-reports, which may be subject to bias. Additionally, the study did not take into account the intensity or total energy expenditure of physical activity, which could further clarify the relationship with depression symptoms.
“Research results are not destiny,” Dubash emphasized. “The relationships in this study are not deterministic, so they do not mean that the effects of exercise on depression, or vice versa, will occur exactly as described for you personally.”
Future research could further examine the mechanisms underlying the relationship between depression and physical activity. “I would like to identify the contributions of social relationships to influence this relationship,” explained Dubash. “Could having friends that you walk with, go dancing with, or go to the gym with influence this relationship in a significant way?
The study, “The Interplay of Depression Symptoms and Physical Activity: Two-Way Insights from 25 Years of the U.S. Life Changing Panel,” was published online April 27, 2024.