Exercise as it relates to Disease/The relationship between exercise behaviour and mental health



This Wiki page is a critical analysis of the paper: M.H.M De Moor, A.L. Beem, J.H. Stubbe, D.I. Boomsma, E.J.C. Ge Geus (2006) 'Regular exercise, anxiety, depression and personality: A population-based study', Preventive medicine, 42, pp. 273–279.

What is the background to this research?
A survey conducted by the Australian Bureau of Statistics (ABS) in 2007 estimated that 45 per cent of Australians had experienced a mental disorder in their lifetime, with 20 per cent experiencing a mental disorder in the previous year. When a person has a condition that affects their mental health, they may have a mental illness or mental health disorder. This includes conditions such as depression, anxiety, schizophrenia and bipolar disorder. Recent studies argue that regular exercise and physical activity can help improve minor to moderate mental health disorders.

The study was conducted to determine whether regular exercise is associated with lower levels of anxiety, depression and personality in a large population sample as a function of gender and age.

Where is the research from?
The study was conducted as part of an ongoing study of lifestyle and health of adolescent and adult twins and their families in The Netherlands. Western European countries, such as the Netherlands, share a similar culture with Australia. The research was attributed to the Department of Biological Psychology, Vrije Universiteit Amsterdam (University of Amsterdam, The Netherlands) and published in the peer-reviewed journal, Preventive Medicine. The University of Amsterdam has an excellent reputation for academics and research. Therefore, the studies credibility and validity can be relied upon.

What kind of research was this?
A population study was conducted to examine whether regular exercise is associated with anxiety, depression and personality. The population sample consisted of adolescent and adult twins and their families. Exercise participation, anxiety, depression and personality were assessed with self-report questionnaires every two years over and eleven-year period (1991–2002). Cross-sectional analysis was used to process the data. Analysis of cross-sectional data consists of comparing the differences among selected subjects, in this case subjects were separated into age and gender specific groups.

What did the research involve?
All subjects were volunteers and were asked to complete surveys on lifestyle every two years. The total number of participants in the study was 19,469. A number of subjects were excluded due to age (under 10 years) or if their exercise behaviour was unknown. Regrettably only 37.5% of participants (n=7,241) completed more than 3 surveys. Exercise participation was measured during each survey, this information was derived from exercise type, duration and frequency. Subjects were classified as an 'exerciser' if they exercised at least 60 minutes per week at or above 4 METs. Further to this, the survey measured four variables reflecting anxiety, depression and personality traits.

Limitations

 * Self reporting bias. Multiple studies have displayed subjects tend to over report the total exercise undertaken. Understanding self-reporting bias and how it can affect research conclusions is important to ensure the validity of findings.
 * The use of Metabolic Energy Expenditure Index (METs) in classifying a subject as an 'exerciser' or 'non-exerciser'. The METs method involves estimating intensity of exercise and physical activity, however most subjects have a different perception of exercise intensity. This estimation is quite subjective and varies widely across populations.
 * The exercise requirement of the participants (60 minutes per week at 4 METs) does not appear to be based on scientific evidence. The Government of the Netherlands recommends 30 minutes of exercise (intensity not specified) at least five times per week, this may have been a more standardised approach.

Strengths

 * The study consisted of a large cohort (n=19, 288) distributed across gender, age and socioeconomic backgrounds.
 * The study was conducted over an extended period of 11 years

What were the basic results?
Linear mixed modelling was used to test for differences in means on anxiety, depression and personality traits between exercisers and non-exercises. A summary of the results is displayed in the table below.

What conclusions can we take from this research?
The research supports previous findings that exercise and physical activity are associated with lower levels of depression and anxiety. The subjects also displayed an improvement in social skills, a greater sense of sensation seeking and were further extraverted than the non-exercises. This research is useful for mental health practitioners and mentors who may be dealing with minor to moderate cases of degraded mental health. Although the findings between exercises and non-exercises was small, these differences were consistent across both age and gender. The study does not however, attempt to explain the reverse causality between mental health and exercise. Further studies are required to determine how much of an impact mental illnesses have on exercise. Finally, it is important to understand that this particular study was focused on the effects exercise can have on anxiety, depression and personality traits. There are many more types of mental illness such as bipolar disorder and schizophrenia that require further research.

Practical advice
Subjects experiencing minor to moderate mental health issues should aim to incorporate regular exercise into their daily routine. The Word Health Organization recommends a minimum of 150 minutes with physical activity of moderate intensity during each week for adults 18 years or older. Those individuals who are inexperienced with physical activity should seek out an appropriately qualified fitness instructor before commencing exercise. There is very little evidence to suggest severe mental health illnesses can be influenced through exercise, appropriate care should be provided in these circumstances, including care from medically qualified practitioners. For severe mental health disorders consult a GP, Psychologist, Psychiatrist or Exercise Physiologist prior to exercising.

Further information/resources
Follow the below links for further information regarding the relationship between mental health and exercise.

Beyond Blue: https://www.beyondblue.org.au/personal-best/pillar/supporting-yourself/exercise-your-way-to-good-mental-health

Black Dog Institute: https://www.blackdoginstitute.org.au/get-involved/exercise-your-mood

Victoria Health: https://www.betterhealth.vic.gov.au/health/healthyliving/exercise-and-mental-health

For immediate assistance contact lifeline: https://www.lifeline.org.au/get-help/topics/lifeline-services