Exercise as it relates to Disease/The effect of exercise intensity on women with depression

What is the background to this research?
Depression is a serious mental disorder present throughout the world, and women are twice as likely to suffer from it. Despite the availability of pharmaceutical and psychotherapeutic treatments for depression, only 51.6% of adults suffering from Major Depressive Disorder (MDD) seek treatment, with only a further 21.7% being effectively treated. Due to the social stigma surrounding traditional treatments for MDD (anti-depressants, therapy etc.), exercise is deemed ‘socially acceptable’ due to its fewer side effects and other health benefits. Therefore exercise can be a more satisfactory treatment for some (not all) individuals with depression. Further studies indicate that exercise training (structured or not) is as effective as antidepressant medication and psychotherapy.

Where is the research from?
All four authors have been published within well-known journals (The Journal of Sport and Exercise Psychology, international Journal of Mental Health and Addiction) therefore aiding us in trusting this is a reliable source.


 * Hua Chu, Department of Family and Preventative Medicine, University of California
 * Janet Buckworth, Health and Exercise Science, The Ohio State University
 * Timothy E. Kirby, Health and Exercise Science, The Ohio State University
 * Charles F. Emery, Department of Psychology, The Ohio State University

What kind of research was this?
This design of study had one between subject factor (group assignment- 3 levels) and one within-subject factor (time - 3 levels). This design of study could also be categorised as a randomised control study of sedentary* female volunteers (aged 18-43) with depressive symptoms (a score of 14-28 on Beck Depression Inventory –II). However written consent from a physician or other health care professional to participate was required for any female scoring above 28 on BDI-II.

These volunteers were randomly assigned to one of two aerobic exercise groups (high intensity or low intensity), or to an exercise control group consisting of flexibility and stretching exercises. This randomisation was accomplished by drawing the names of participants from a bag. This form of study helps reduce bias, aids in statistical consistency and is considered the most reliable intervention due to the processes used which help minimise the risk of different factors influencing the results.


 * exercising less than three times a week for less than twenty minutes a session

What did the research involve?
After completing all baseline assessments (BDI-II, maximal oxygen intake, exercise self-efficacy* and depression coping self-efficacy), participants were informed of their group assignment and all participants began their training program within a two-week window of their baseline evaluation.

Over the course of the selected 10-week training program, each group met with the investigator once a week for a supervised exercise session. Aerobic group participants (both high intensity and low intensity) exercised on a treadmill for 30-40 minutes and those in the stretching control group performed 30 minutes of supervised stretching and flexibility exercises. The aerobic participants were also asked to complete three to four unsupervised aerobic exercise sessions each week.


 * Participants rated confidence from 0% (cannot do it at all) to 100% (certain I can do it) in their ability to exercise under a number of different conditions (mood, weather) over the course of the 10 weeks.

What were the basic results?
Of the initial 54 participants, 16 (30%) did not finish the 10-week training program (three from high intensity, seven from low intensity, and six from the stretching control). The major reasons for drop out were lack of time for exercise, and a low compliance with the assigned intensity of exercise. There were no significant differences between the participants who completed the study and those who didn’t, except for antidepressant use. A significant amount of participants who dropped out were taking antidepressants at study entry.

The remaining participants who completed the full 10-week program revealed significant improvements over time in their BDI-II scores. Overall the average BDI-II score decreased significantly from 22.5 at study entry, to 13.9 at 5 weeks and continued to decrease to 11.3 at 10 weeks.

What conclusions can we take from this research?
According to the results of this 10-week program, it suggests that high intensity and low intensity aerobic exercise as well as stretching exercise contribute to a reduction in depressive symptoms. However, when comparing the BDI-II scores between each group, participants in high intensity presented significantly fewer depressive symptoms at both weeks 5 and 10, where low intensity and stretching did not differ greatly at either time point.

If we were to go off these results then we can assume a high intensity aerobic exercise may be more effective at reducing symptoms of depression in the long term. However, since there were no significant reductions in depression between each of the groups, there would need to be further investigation into whether high intensity exercise really is necessary for improving symptoms of depression.

Despite the results, there is also the possibility of a placebo effect since the stretching control group also showed significant improvements in their depressive symptoms. There’s the possibility that participants expectations, the social aspect and personal attention given by the investigator and study could also have contributed to an improvement in depressive symptoms. Therefore, despite stretching being used as a placebo control, may also be an effective treatment for depressive symptoms.

There were also a number of limitations to this study. Unsupervised exercise sessions relied on self-analysis to measure participant’s behaviours and so therefore possible that participants would either overestimate the intensity and duration, underestimate it, record extra sessions or not exercise at all.

The study claims that both high and low intensity aerobic exercises as well as stretching exercise were associated with depressive symptoms reductions over the 10-week training period. Therefore we can assume that although high intensity exercise may affect depressive symptoms more effectively, it can be said that low intensity exercise and stretching have an effect also and so the extent of exercise intensity doesn’t really have a massive effect on the reduction of depressive symptoms.

Practical advice
Regular exercise for patients suffering from depressive symptoms can be an effective treatment by itself or alongside other treatments like therapy, medication etc. and can then increase a sense of control, social support and self esteem in the individual.

Due to the low cost and simplicity, exercise and physical activity can be a beneficial intervention for those suffering from depression (mild to severe). However due to lack of motivation, self esteem and other mind blocks in some patients it can be beneficial to seek professional help or advice.

Even if exercise causes little to no improvements initially; exercise is low risk and is advantageous to a patient’s health and fitness regardless and eventually may improve their self-esteem or self love once they see a change. Exercise alongside other treatments like therapy and a solid support system, can help improve an individuals well being, mental stability, improved motivation and a better outlook in the general sense.

Further information/resources

 * If you are interested in taking up an exercise program, please contact your GP for health advice, and see a personal trainer for an exercise program to help you reach your goals.


 * If you or someone you know is may be experiencing depression, please contact Beyond Blue on 1300 22 4636 or reach them at https://www.beyondblue.org.au/


 * If you or someone you know is suicidal call lifeline on 13 11 14 or https://www.lifeline.org.au/