Physical exercise in the treatment of depression in the elderly: a systematic review

Abstracts

OBJECTIVES: To review the literature on the (I) possible protective effect of physical activity on the incidence of depression, and (II) on the efficacy of physical exercise as a therapeutic intervention in depression. METHODS: Systematic review of ISI, PubMed, LILACS and SciELO articles in English and Portuguese from January 1993 to May 2005 using the keywords "depression," "elderly," and "exercise." Articles assessing the effect of physical exercise in the elderly with clinical diseases or that used depression scales only for initial diagnosis were excluded. RESULTS: We found 155 articles, 22 of which met the inclusion criteria. Other eight studies were included after a manual search. Cross-sectional studies (n = 8) used only self-evaluation questionnaires to measure the levels of physical activity. Longitudinal studies (n = 22) also used digital pedometer, direct measurements of oxygen consumption and physical exercise as methodological intervention. The studies meeting the first objective pointed to an inverse relationship between physical activity and changes in levels of depression. The studies that used physical activity as a therapeutic intervention in depression found divergent results and pointed to the interference of physiological and psychological factors on this relation. CONCLUSION: There are two aspects involved in the role of physical activity and exercise in the treatment of depression. Depression decreases the practice of physical activities; physical activity may be useful in the treatment and prevention of depression in the elderly.

Depression; elderly; physical activity; exercise; systematic review

OBJETIVOS: Revisar a literatura quanto (I) ao possível efeito protetor do exercício físico sobre a incidência de depressão e (II) à eficácia do exercício físico como intervenção no tratamento da depressão. MÉTODO: Revisão sistemática de artigos em inglês e português nas bases ISI, PubMed, SciELO e LILACS de janeiro de 1993 a maio de 2006, utilizando conjuntamente os termos "depressão", "idosos" e "exercício". Artigos que avaliaram o efeito do exercício em idosos com doenças clínicas ou que utilizaram escalas para depressão somente para um diagnóstico inicial foram excluídos. RESULTADOS: Do total de 155 artigos, 22 atenderam aos critérios de inclusão, e oito foram acrescentados com busca manual. Os artigos de corte transversal (n = 8) utilizaram somente questionários de auto-avaliação para medir os níveis de atividade física. Os artigos longitudinais (n = 22) utilizaram também pedômetro digital, consumo direto de oxigênio e o exercício físico como intervenção metodológica. Os estudos que atenderam ao objetivo I apontaram para uma relação inversamente proporcional entre atividade física e alterações nos níveis de depressão. Os trabalhos que utilizaram o exercício como intervenção terapêutica na depressão encontraram resultados divergentes e apontaram para a interferência de fatores fisiológicos e psicológicos nessa relação. CONCLUSÃO: O papel do exercício e da atividade física no tratamento da depressão direciona-se para duas vertentes: a depressão promove redução da prática de atividades físicas; a atividade física pode ser um coadjuvante na prevenção e no tratamento da depressão no idoso.

Depressão; idosos; atividade física; exercício; revisão sistemática

REVIEW ARTICLE

Physical exercise in the treatment of depression in the elderly: a systematic review

Helena Moraes^I; Andréa Deslandes^II; Camila Ferreira^III; Fernando A. M. S. Pompeu^IV; Pedro Ribeiro^V; Jerson Laks^VI

^ILaboratório de Mapeamento Cerebral e Integração Sensório–Motora, Instituto de Psiquiatria – Universidade Federal do Rio de Janeiro (IPUB–UFRJ), Rio de Janeiro, RJ, Brazil. Centro de Alzheimer e Outros Transtornos Mentais na Velhice, IPUB–UFRJ, Rio de Janeiro, RJ, Brazil

^IILaboratório de Mapeamento Cerebral e Integração Sensório–Motora, IPUB–UFRJ, Rio de Janeiro, RJ, Brazil. Centro de Alzheimer e Outros Transtornos Mentais na Velhice, IPUB–UFRJ, Rio de Janeiro, RJ, Brazil. PhD student, Graduate Program in Psychiatry and Mental Health, IPUB–UFRJ, Rio de Janeiro, RJ, Brazil. Scholarship holder, Coordination and Improvement of Higher Level Personnel (CAPES)

^IIILaboratório de Mapeamento Cerebral e Integração Sensório–Motora, IPUB–UFRJ, Rio de Janeiro, RJ, Brazil. MSc. student, Graduate Program in Psychiatry and Mental Health, IPUB–UFRJ, Rio de Janeiro, RJ, Brazil. Scholarship holder, National Counsel of Technological and Scientific Development (CNPq)

^IVDepartment of Biosciences and Physical Activity, UFRJ, Rio de Janeiro, RJ, Brazil

^VLaboratório de Mapeamento Cerebral e Integração Sensório–Motora, IPUB–UFRJ, Rio de Janeiro, RJ, Brazil. Department of Biosciences and Physical Activity, UFRJ, Rio de Janeiro, RJ, Brazil

^VICentro de Alzheimer e Outros Transtornos Mentais na Velhice, IPUB–UFRJ, Rio de Janeiro, RJ, Brazil

^{Correspondence}

ABSTRACT

OBJECTIVE: To review the literature on the (I) possible protective effect of physical activity on the incidence of depression, and (II) on the efficacy of physical exercise as a therapeutic intervention in depression.

METHOD: Systematic review of ISI, PubMed, LILACS and SciELO articles in English and Portuguese from January 1993 to May 2005 using the keywords "depression," "elderly," and "exercise." Articles assessing the effect of physical exercise in the elderly with clinical diseases or that used depression scales only for initial diagnosis were excluded.

RESULTS: We found 155 articles, 22 of which met the inclusion criteria. Other eight studies were included after a manual search. Cross–sectional studies (n = 8) used only self–evaluation questionnaires to measure the levels of physical activity. Longitudinal studies (n = 22) also used digital pedometer, direct measurements of oxygen consumption and physical exercise as methodological intervention. The studies meeting the first objective pointed to an inverse relationship between physical activity and changes in levels of depression. The studies that used physical activity as a therapeutic intervention in depression found divergent results and pointed to the interference of physiological and psychological factors on this relation.

CONCLUSION: There are two aspects involved in the role of physical activity and exercise in the treatment of depression. Depression decreases the practice of physical activities; physical activity may be useful in the treatment and prevention of depression in the elderly.

Keywords: Depression, elderly, physical activity, exercise, systematic review..

Introduction

Depression is among the leading public health problems worldwide, due to its high morbidity and mortality rates.¹ In the USA, it reaches around 9.5% of adults per year. Its incidence is estimated in approximately 17% of the world population.² Some of its main characteristics are weight loss, feeling of guilt, suicidal ideation, hypochondria, complaint of pain and occasionally psychosis. These symptoms are more marked in depressed elderly than in depressed young and contribute to a decline in cognition³ and in cardiorespiratory fitness⁴ in that age group.

Although there are more than eight classes of antidepressants available, with approximately 22 active substances in the international market for a pharmacological treatment of depression, only 30–35% of depressed patients do not respond to psychotropics.⁵ In well–controlled and double–blind studies, response is defined as a 50% reduction in symptoms observed by means of depression assessment scales, whereas remission is defined as a total improvement.⁶ For eventual remission, therefore, it is necessary to use other treatment methods associated with drugs.

In a recent review article, Frazer et al.⁷ suggest that, among other methods, physical activity can be considered efficient in the treatment of depression. Physical activity means any body movement produced by skeletal muscles resulting in energy expenditure greater than that of rest levels. On the other hand, exercise is a planned, structured and repetitive physical activity, whose final or intermediate goal is to increase or maintain health/physical fitness.⁸ Both activity and exercise can provide acute and chronic benefits. Among them are improvement in physical fitness; reduction in bone and muscle loss; increase in strength, coordination and balance; reduction in functional ability, intensity of negative feelings and physical diseases; and promotion of improvement in well–being and mood.⁹ However, the effects of practicing physical activities on depression are still contradictory. Some studies associate changes in depression status as resulting from practicing activities,^10–12 whereas other studies^1,13 relate a more frequent practice of exercises to improvement in severity of depressive disorder. In this context, this study aims at (I) reviewing the literature on the possible protective effect of physical activity on the incidence of depression in the elderly; and (II) evaluating the efficacy of physical exercise as a therapeutic intervention in depression.

Method

A search for ISI, PubMed, LILACS and SciELO articles from January 1993 to May 2005 was performed, using the keywords "depression," "elderly," and "exercise," and the following limits: humans, english, clinical trial + randomized controlled trial, middle aged: 45 + years, NOT review, NOT animals NOT heart NOT failure. Longitudinal and cross–sectional studies were selected, besides additional references found in the references of those articles, using the methodology aforementioned, which were captured and that met the inclusion criteria for this study. Exclusion criteria were articles assessing the effect of exercises in the elderly with comorbid clinical diseases (such as diabetes mellitus, hypertension, and heart disease) and using depression scales only for initial diagnosis, with no intention of assessing changes occurred after the intervention of physical exercises. All abstracts were initially evaluated independently by two raters. Those approved by both of them were included in the study. Those that had disagreement were submitted to a third rater.

Results

A total of 88 articles were found in ISI, 62 in PubMed, four in LILACS and one in SciELO. Redundant cross–references, which were present in more than one database, were removed, selecting 22 articles and adding eight. Articles not accepted for this review (n = 130; 74 in ISI, 53 in PubMed, two in LILACS and one in SciELO) were excluded due to the following factors: not possible to obtain the complete version (n = 14; nine ISI, five PubMed); aimed at using physical activity for motor or heart rehabilitation and applied depression scales only for initial diagnosis (n = 37; 14 ISI, 23 PubMed); analyzed other psychological disorders (n = 2; one ISI, one PubMed); analyzed the benefits of physical activity, but not directly associated with depression (n = 58; 44 ISI, 11 PubMed, two LILACS, one SciELO); analyzed the association of other factors with depression (n = 19; six ISI, 13 PubMed).

The studies meeting the first objective pointed to an inverse relationship between physical activity and changes in levels of depression. The studies that used physical activity as a therapeutic intervention in depression found divergent results and pointed to the interference of physiological and psychological factors on this relation. Table 1 and 2 present the studies, separating them according to the objectives of the present study, ordered into longitudinal and cross–sectional studies.

Discussion

Physical activity and depression: cause and effect relationship

In general, studies aiming at observing the cause and effect relationship between practice of physical activity and changes in depression levels indicate a negative relationship. Recent findings support two different theories to explain the relationship between physical activity and depression. The first theory indicates the practice of physical activity as a factor influencing reduction in intensity of depressive symptoms. Lampinem et al.¹¹ verified that elderly individuals who reduced activities after 8 years had an increase in depressive symptoms, whereas the individuals who increased or maintained intensity of activities did not have the same effect. Similar results were found by studies assessing training using other quantitative instruments, such as oxygen consumption⁴ and digital pedometer.¹² The second theory focuses on the influence of depression on physical activity. By analyzing 1,920 elderly individuals for 6 years, van Gool et al.¹³ verified that those who became depressive were more likely to lead a sedentary lifestyle than those without depression. Therefore, depression would result in a decreased general physical fitness condition. Although involving a large number of subjects, the study design allows us to state that there is an association between decreased physical exercise and depression, but not a cause and effect relationship, since there was no chronologic follow–up of the event.¹³

Cross–sectional studies showed divergent results. Anton & Miller¹⁵ and Bailey & McLaren¹⁹ did not find any significant positive relationship for protection against depression caused by physical activity. Some limitations of this study were the use of a small sample (n = 23)¹⁵ and the use of self–administered questionnaires to quantify physical activity.¹⁹ Other studies^17,20 using the same methods and a larger sample verified that sedentary lifestyle and age are factors positively related to depression, especially when controlling for the age factor. Besides sedentary lifestyle, quitting activities and dissatisfaction with physical activity can also be associated with high depression levels.¹⁰ Since it is a cross–sectional study, it is not possible to determine whether replacement of physical activity is a cause or consequence of reduction in depression.

Two hybrid studies assessed the protective effect of physical activity on depression, using cross–sectional and longitudinal analysis, and presented contradictory results.^1,16 In cross–sectional analyses, less active elderly individuals had higher risks of depression than more active elderly individuals. In longitudinal analyses, Strawbridge et al.¹ found a direct relationship between incidence of depression and reduction in practice of physical activity, whereas Kritz–Silverstein et al.¹⁶ did not obtain the same results. Discrepancies between these results can be explained by the difference in some sample variables. The first study used functional incapacity in the elderly as exclusion factor, and the second study did not use this limitation. Penninx et al.¹⁴ followed 6,247 elderly individuals for 6 years and verified that those who presented more depressive symptoms significantly reduced performance in daily tasks. Such results could be partially explained by reduction in physical activity and social interaction. Many studies corroborated the fact that depression can trigger impairment in functional ability in daily activities (having a shower, eating, getting dressed) and in mobility (walking half a mile or climbing stairs without help).^37–39 The lack of independence to perform those activities can be associated with chronic physical pain,³⁸ physical inactivity^18,27,37 and fear of falls.⁴⁰ Exercise routines that included stretching, balance, walking, strength and coordination proved to be efficient in reducing depression levels in elderly individuals with history of falls.¹⁸

Physical exercise as therapeutic intervention in depression

Some studies used exercises as therapeutic intervention in depression and proposed that their results could be due to psychological and/or physiological factors.^29,35 To test physiological factors, two studies^5,36 compared changes in depression levels in elderly individuals randomized into three groups: exercise, drugs and combined (drugs and exercise). The exercise group was monitored as to intensity and frequency of training. Reduction in depression occurred in all three groups, with no significant difference between them. After 6 months, a new analysis^5,21 of the same sample was performed, with no randomization, concluding that the longer the time spent on exercises, the lower the depression levels. In addition, the exercise group had more recovery and fewer recurrences than the other groups. According to the authors, combining drugs and exercises can generate results different from those found only with training, since it does not assure a feeling of self–confidence in individuals, who attribute improvements to the drugs.

Kohut et al.²⁸ associated reduction in depression, after 10 months of physical exercise, with changes in the immune system. A possible explanation for these results is the release of hormones such as epinephrine, norepinephrine, somatotrophin, ?–endorphin and cortisol, which reach specific receptors located in lymphocytes and macrophages, causing an increase in concentration of those cells.

To observe psychological effects, many studies compared psychological and social interventions, such as therapists' visits, group work or lectures with exercise. Lai et al.³² found a significant reduction in depressive symptoms immediately after 3 months of exercises in elderly individuals rehabilitated from acute myocardial infarction. The same result was not found in those who received psychological interventions with therapist's visits. The groups were reassessed 6 months later, and even without any type of intervention during that period, they significantly reduced depression levels. However, in that stage, there was no control as to use of drugs.

According to the same line of research, Mather et al.²² found a significant reduction from 55 to 30% in depression levels, when submitting 86 elderly individuals to collective gymnastics classes or meetings and lectures with psychologists for 12 weeks, respectively. McNeil et al.²³ analyzed two types of symptoms (psychological symptoms: feeling of uselessness, loss of interest in usual activities and mood disorders; and somatic symptoms: loss of appetite, fatigue and sleep disorder) in elderly individuals who performed exercises or received visits by psychologists. Both reduced the two types of symptoms, but only the exercise group significantly reduced somatic symptoms.

Divergent results were found by Castro et al.³⁴ in elderly individuals randomized into intervention with exercises and follow–up by a nutritionist. Despite finding reduction in depression levels in both groups, follow–up was carried out only through telephone calls, reducing reliability of results. Rybarczyk et al.²⁵ compared supervised and non–supervised exercises in depressive and non–depressive elderly patients. Significant reduction in symptoms was only found in the depressive group that practiced supervised physical exercise.

Different exercise modalities were used in some studies to compare efficacy of results. Motl et al.³³ compared endurance and flexibility and aerobic exercises, performed with the same duration and frequency in elderly patients with no clinical status of depression. Although both had reduced depressive symptoms soon after intervention, aerobic exercises generated better results. Paw et al.²⁶ did not find any difference between endurance training and playful activities. However, methodological limitations impaired measurement of training intensity, and the participants could not increase intensity of the exercise program. Singh et al.³⁰ compared different levels of strength training intensity and observed a reduction in depressive symptoms in both groups, but better results in the high–intensity group. King et al.²⁴ did not find any difference in results by comparing different intensities of aerobic exercises. However, frequency of activities was a determining factor in reduction in depressive symptoms. Haboush et al.³¹ offered ballroom dance lessons in depressive elderly people for 8 weeks, only once a week, and did not obtain results in depressive symptoms.

Reduction in depression with exercises and physical activity: possible neurochemical explanations

Although they present significant results in the treatment of depression, the mechanisms by which physical activity provides antidepressant effects are speculative. As an attempt to clarify them, it is necessary to have an understanding on neurobiology and neuropsychology of depression. There are variations in blood flow and in the prefrontal cortex metabolism (area associated with attention, psychomotility, executive ability and decision making); hyperactivity in the subgenual prefrontal cortical region (which generates sad thoughts); and increase in glucose metabolism in several limbic regions, with emphasis on the amygdala (emotional learning).⁴¹ Furthermore, changes in regulation of the hypothalamus–pituitary–adrenal axis (cortisol hypersecretion) are associated with depressive disorder.⁴²

Neurocognitive changes are observed in depressive elderly people, such as impairment in attention, memory, processing speed, executive function, emotion and decision making.⁴¹ One of the factors that can explain memory deficit in depression is hippocampal change due to hypercortisolemia, reduction in brain–derived neurotrophic factor (BDNF) and reduction in neurogenesis.² Physical exercise contributed to the development of neurogenesis in the hippocampus through long–duration potentiation and BDNF, as antidepressants and electroconvulsive therapy.^43,44

The most accepted hypothesis in the literature is an increase in monoamines, such as serotonin, dopamine and noradrenaline.⁷ The process of serotonin biosynthesis can occur due to increase in its tryptophan precursor in the brain, influenced by exercises.⁴⁵ Kiive et al.⁴⁶ verified high blood levels of prolactin during aerobic exercise, reflecting a major increase in serotonin. Serotonin can mitigate formation of memories associated with fear and reduce responses to threatening events through serotoninergic projections that part from the raphe nucleus to the hippocampus.⁴⁷

Exercises can also be associated with dopamine synthesis due to increased calcium levels in the brain, through the stimulus of an enzyme system known as calcium/calmodulin.⁴⁸ Dopamine is associated with motor performance, locomotor motivation and emotional modulation.⁴⁹

Prescription of exercises and physical activity in depression

For the population aged 65 years or more, the American College of Sports Medicine (ACSM)⁵⁰ recommends aerobic activity using 40–60% of heart rate reserve, or 11–13 in Borg scale, with duration of 20 minutes and frequency of three times a week. Review articles conclude that activities such as walking and running are the most used treatments for severe depression levels.^7,51 Meyer & Broocks⁵² showed that, for an effective reduction in depressive symptoms, it is necessary to prescribe exercises with duration of 30 minutes and 50–60% of VO2max, or 12–14 in Borg scale, claiming that long and less intense activities are preferable, since they interrupt depressive thoughts with higher efficiency. Considering that most depressive patients lead a sedentary lifestyle, frequency of two to four times a week is recommended. It is necessary to perform functional reevaluations between 10 and 12 weeks of training, to adequate exercise intensity to improvements in physical fitness. However, most articles concluded that total time spent on exercises, directly associated with adherence, is the most important variable to assess outcomes of practicing exercises.^24,26,50,52

Strength training can also be used to increase functional ability, reducing dependence on daily activities due to feeling of fall, frailty, loss of bone mass, as well as risk of chronic diseases.⁵³ For that type of training, ACSM⁵⁰ recommends two to three series of exercises, with frequency of twice a week, but preferentially three. Seguin & Nelson⁵³ suggest training volume with two to three series for four exercises, one to two series for four to eight exercises and one series for eight exercises or more.

Conclusion

The relationship between the role of exercise and physical activity in the treatment of depression follows two paths: depression decreases the practice of physical activities; physical activity may be useful in the treatment and prevention of depression. However, more studies are necessary using control group, homogeneous population, scales and reliable tests, monitoring of physical exercise and new instruments for brain scanning to corroborate these findings. Taking into account the physical and psychological benefits from general physical activity and exercise particularly, it can be concluded that their practice by depressive elderly individuals with no comorbid conditions is able to prevent and reduce depressive symptoms.

References

Received June 20, 2006.

Accepted November 14, 2006.

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Publication Dates

• Publication in this collection
  06 Sept 2007
• Date of issue
  Apr 2007

History

• Received
  20 June 2006
• Accepted
  14 Nov 2006