skip to main content

Dr Jo Blodgett, Research Fellow at The Institute of Sport, Exercise and Health (ISEH) and University College London (UCL) has led research that investigated the complex associations between moderate or high intensity activity, depression and poor physical function in middle-age. 

This research was conducted in collaboration with researchers from ISEH and UCL, this being, Research Fellow in Epidemiology, Dr Tom Norris, Associate Professor in Population Health and Applied Statistics, Dr Snehal Pinto Pereira and Chair in Sport and Exercise Medicine, Professor Mark Hamer.
Although mental health, physical health and physical activity are intrinsically linked, there is a need for further understanding about how they work together and the impact this has on health and wellbeing.

The authors looked at the data of two large studies of individuals born within a single week in 1958 and in 1970 (more than 13 000 participants) to effectively explore the various complex associations between moderate or high intensity activity, depression and poor physical function in middle-aged.
Their study revealed that individuals with depression at age 33 or 34 participated in less moderate and high intensity activity at age 42,  and also had about 15-20% worse physical function at age 46. Additionally, they found that higher levels of moderate and high intensity activity were linked to better physical function.  

As a result of these associations, the authors wanted to explore if exercise mediated the association between depression and physical function. In other words, what is the mechanism by which individuals with depression have poorer physical function? Together they hypothesised that this was because they tended to engage in less exercise, which then contributes to worse physical function. However, the authors found only very small evidence of mediation- the total proportion mediated was 3% in the group born in 1970, with no effect in those born in 1958. 

Dr Jo Blodgett comments on the findings of this research and said: “We found consistent evidence that depression was linked to lower MVPA participation and lower physical function in midlife. These associations were independent of lifetime socioeconomic position, marital status, childhood and familial mental health, health behaviours and other markers of physical health.

It was unsurprising to observe positive association between MVPA frequency and physical function. Increasing aerobic and resistance training in middle and older aged adults can directly improve functional outcomes. Participation in strenuous exercise yields benefits across cardiometabolic and musculoskeletal systems, while inactivity contributes to increased inflammation and adiposity; deficiencies in any of these areas can cause impaired physical function.

As there was only minimal evidence of mediation, we must expand beyond only high intensity activity to encapsulate other aspects of PA, and investigate how all movement across the day (e.g., sedentary behaviour, sleep) play a role.”

Read the published paper in Science Direct, Journal of Affective Disorders.