Mats Hallgren. Photo: Private.

Mats Hallgren

Principal researcher

About me

Principal researcher: Epidemiology of Psychiatric Conditions, Substance use and Social Environment (EPiCSS); Department of Global Public Health, Karolinska Institutet.

Editor in Chief: Mental Health and Physical Activity (Elsevier) - impact factor = 5.9

>120 peer reviewed publications (H-index=36, >6000 citations)

Research description

I lead a program of research focused on links between physical activity/inactivity and mental health. Recently completed projects include FitForChange - a community-based randomized controlled trial (RCT) of exercise as treatment for alcohol use disorder. I designed and led to completion (2020) a dual site (Sweden-India) trial of yoga and aerobic exercise to promote wellbeing in physically inactive older adults: FitForAge. Other completed projects include the largest international trial of exercise for depression (Br J Psychiatry 2015/16), and a trial of exercise for first episode psychosis (Psychol Med, 2018).

In addition to this experimental work, I have led a series of large-scale observational studies examining relationships of sedentary behaviour (sitting) and depression. An important finding of my research is that these relationships are influenced by cognitive activity (mentally-passive versus mentally-active). This work is presented in an invited article in a leading sports science journal (Ex Sport Sci Reviews, 2020).

In 2023 I will lead a new randomized controlled trial of yoga-based exercise in the treatment of post-COVID 19 condition (also known as long COVID). I am also co-investigator for an ongoing trial examining the effects of High Intensity Interval Training (HITT) on cognition and brain function in poly-substance dependent inpatients.

My research vision is to build a broader evidence base for the role of physical activity in the prevention and treatment of mental health conditions, identifying new options with the potential for greater acceptability, reach, and effectiveness. My highly cited research has impacted clinical and public health practice in Sweden, India, and Australia. I am regularly invited to discuss my work on radio, podcasts, and the print media. I have also appeared on national television.


Teaching portfolio

I lead courses and seminars on physical activity and mental health in Sweden and abroad. I also supervise master and PhD students in public health sciences.


  • PhD; Department of Public Health Sciences, Karolinska Institutet, Sweden
  • Master of Health Promotion, Karolinska Institutet, Sweden.
  • Post-graduate Diploma in Applied Science (Professional Psychology), Federation University, Australia
  • Bachelor of Arts (Psychology) - University of Melbourne, Australia.