Exercise as it relates to Disease/The effects of aerobic exercise on major depression

This page is an analysis and critique of the article "Benefits from aerobic exercise in patients with major depression: a pilot study" by Fernando Dimeo et al (2001).

What is the background to this research?
Major depression is when an individual experiences an intense, prolonged episode of low feelings. These episodes can last up to many months or years and impact a person's ability to receive enjoyment out of everyday activities. Many sufferers are unable to complete everyday tasks such as going to school or work.

Depression is extremely prevalent throughout the world and Australia. In 2007 the Australian Bureau of Statistics stated that 14% of the population at the time were living with depression. Due to a population growth and recent trends it is likely that this number has since grown. In the past it has been suggested that exercise may have a positive effect on depression. This study explores this possibility and has a significant real-world application as it looks to provide a foundation for more research in this area and assist in finding an effective, cost-effective solution to major depression.

Where is this research from?
This study was led by Dr Fernando Dimeo. Dimeo has a long history of researching the benefits of exercise on many different chronic diseases. The research was completed at the University of Berlin and published by the British Journal of Sports Medicine, one of the most prestigious journals in its field, in 2001. There are no organisational links or sponsorships within the team conducting the study that could possibly influence the validity of the results.

What kind of research was this?
The research conducted for this article was a pilot study. Pilot studies are small scale studies that are taken to determine the practicality of a larger study exploring the same hypothesis without having to invest the time and money. Since this is a pilot study and the number of participants was quite small, there is a possibility that the patterns and results in this research may not be accurately represented in a real-world population. The study was observational and involved twelve participants who suffer from major depression partaking in an exercise program. These participants' levels of depression were assessed before and after the program using the 21-item Hamilton Rating Scale for Depression and the Scale for Self-Assessment of Depression. Since this is a pilot study, these tests are suitable due to their simplicity, although it would be beneficial to use more in-depth tests in a full-scale study. Aerobic fitness was also measured through the American College of Sports Medicine guidelines using a Bruce protocol.

What did the research involve?
The research involved seven female and five male participants between the age of 28 and 64 who were all experiencing a major depressive episode according to the Diagnostic and Statistical Manual of American Society of Psychiatric. The mean length of episodes for the patients was 35 weeks with a range between 12 and 96. All participants had been hospitalised for two weeks prior without improvement in condition. There was no indication of the participants prior fitness levels which could have potentially influenced the results.

The research involved all patients participating in an aerobic exercise program at 'somewhat hard' level determined by the Borgs Rate of Perceived Exertion scale. The program consisted of interval training for thirty minutes on a treadmill for ten days with one rest day in the middle. This is quite a low volume and does not even meet the 2014 Australian physical activity guidelines. Due to this, it would have made more sense for the participants to participate in a higher volume of exercise for better results. The participant selection criteria involved the patient not changing their pharmacological or psychotherapy treatments within six weeks prior to the study. The methodology in this study was appropriate in the sense that it was not too invasive or intense for the participants, which is a consideration for those with depression. There was no mention of risk prevention during or pre-screening for cardiovascular risks. This is an extremely important requirement when conducting any research that involves participants exercising.

The criteria for selecting participants was suitable as it included a large range of age and explored participants who have been suffering major depression episodes for various lengths of time. It was also appropriate that there were guidelines in place to restrict changes in pharmacological and psychological treatments as this removed the possibility of the results being influenced by these.

Although the criteria for participant recruitment was sound, there was a possibility of inconsistent results due to the differences between inpatients and outpatients. The inpatients and outpatients may have experienced different moods and levels of depression due to their circumstances and environment that they were in.

What were the basic results?
All the patients successfully completed the intervention with no complications. Five out of the twelve patients showed substantial improvement, meaning their scores halved. Three out of twelve showed a slight improvement where their scores were lower, although not significantly. The other four patients scores remained the same throughout the intervention, none of the patients' moods declined over the duration of the study. The majority of patients' Hamilton and self-assessed scores were lower. There was no increase in aerobic fitness and half of the participants, when asked, wished to continue the exercise program.

The article’s discussion explored how aerobic exercise can cause improvements in a patient's depressive symptoms through different psychological mechanisms. It was also noted that a correlation between the self-assessment scale of depression and Hamilton rating scale results reinforced the that aerobic exercise did have a positive effect on major depression. The study did well in investigating the potential effects of aerobic exercise on major depression. Further investigation should be taken due to the suggestive results that aerobic exercising has a positive influence on depression. The author did not over-emphasise the results in the article and it was concluded that the results created a foundation for ‘cautious optimism’. Due to this an RCT study was begun to further investigate the effects of aerobic exercise, deeming the pilot study successful.

What conclusions can we take from this research?
From this research we can conclude that there are grounds for further investigation within this area. The results did show improvement in the majority of patients but due to the size of the study it is plausible that the results are not representative of the global population. Therefore, we cannot deduce from these results that aerobic exercise definitely has a positive effect on major depression. It should be noted that this study was conducted 18 years ago and there have since been many other studies that agree and have also suggested that aerobic exercise does have a positive effect on depression and other mental health disorders.

Practical Advice
Due to the low-cost and simplicity, exercise interventions could be extremely beneficial for those suffering from major depression. Due to the lack of motivation shown by some patients it would be beneficial to get a professional to help them. Even if the exercise does not cause any improvements, exercise is low-risk and would be beneficial for the patients' health and fitness regardless.

Further information/resources
Depression Help and Information:

BeyondBlue 1300 22 4636

LifeLine 13 11 14

HeadSpace

Black Dog Institute Sydney

Further readings/articles on the effects of aerobic exercise on depression:


 * The effect of exercise on depression, anxiety and other mood states: a review - A Byrne, DG Byrne
 * Long-term effects of aerobic exercise on psychological outcomes - TM DiLorenzo, EP Bargman, R Stucky-Ropp