Abstract
Background:
Late-life depression and anxiety among older adults is an important public health concern. This study examined the effect of a DVD-delivered exercise intervention on the secondary outcomes of depression and anxiety in older adults and the extent to which physical self-worth mediated the relationship between leisure-time physical activity and depression and anxiety.
Methods:
Older adults (N = 307) were randomized to a 6-month flexibility, toning, and balance DVD (FlexToBa™, FTB) or healthy aging DVD control. Self-reported physical activity and questionnaires were administered at baseline and postintervention. Statistical analyses were conducted in the total sample and in a subsample of participants with elevated levels of depression or anxiety.
Results:
FTB participants with elevated depression and anxiety symptoms at baseline had significantly greater reductions in depression and anxiety (d = 1.66 and 2.90) than the control condition (d = 0.77 and 0.73). The effect of physical activity on depression and anxiety was partially mediated by increases in physical self-worth in the total sample but not in those with elevated depression or anxiety.
Conclusion:
A home-based physical activity intervention may be a viable treatment for reducing depression and anxiety in older adults with elevated baseline scores.
Keywords: exercise, mental health, aging
Depression and anxiety have estimated prevalence rates of between 6% and 10% of older adults1 and thus represent an important public health concern for the growing population of older adults in the United States. Depression and anxiety are associated with an increased risk of morbidity; impairments in physical, cognitive, and social function; and declines in psychosocial health.2–6
Recent reviews and meta-analyses indicate that leisure-time physical activity may significantly reduce depression and anxiety symptoms.7,8 Schuch et al7 reported that physical activity interventions that incorporated aerobic exercise at moderate to vigorous intensities had a large effect on depression (d = −0.90), and Stubbs et al8 reported that physical activity interventions decreased anxiety symptoms more than the control conditions (standardized mean difference = −0.582). Physical activity is an appealing behavioral modality for improving negative affect, as it is low to no cost, easily accessible, has few risks, and is associated with a myriad of positive health benefits. Studies have also demonstrated that after participation in a physical activity intervention, psychosocial factors such as physical self-worth (PSW) may influence negative affect (eg, depression, anxiety).9–11 The PSW domain is informed by subdomains (eg, physical condition, body attractiveness, physical strength).12 Thus, by participating in a physical activity intervention, older adults may improve perceptions of their physical condition, attractiveness, or strength, thereby reducing negative affect. For example, Motl et al10 demonstrated that PSW had a direct effect on changes in depression symptoms in older adults after participation in a walking or a stretching and toning condition. Although limited data exist examining PSW effects on anxiety in older adults, studies have shown that other psychosocial outcomes such as global self-esteem, which is directly influenced by PSW, may be associated with anxiety symptoms13; however, research is warranted in the area of PSW and anxiety.
Structured, group- and center-based physical activity trials have consistently demonstrated positive effects on depression and anxiety in older adults.14,15 Unfortunately, interventions that target populations with limited access to group-based facilities (eg, rural populations, travel difficulties) or who have physical limitations that might prevent them from accessing such facilities are quite rare in the literature. McAuley et al16,17 developed a 6-month, DVD-delivered flexibility, toning, and balance (FlexToBa™, FTB) intervention, which improved physical function, strength, and flexibility at postintervention, 12 months, and 24 months,17–19 and also improved physical activity and self-esteem levels posttrial.20,21 The objectives of this study were to examine the differential effects of the intervention and a control condition on the secondary outcomes of depression and anxiety and whether changes in PSW mediated the effects of changes in physical activity with decreases in depression and anxiety across the trial. Because the effects of exercise on depression and anxiety are likely to be attenuated in nonclinical samples, we also conducted exploratory analyses examining whether effects of the intervention were more potent in those participants who reported symptoms of elevated depression.
Methods
Participants
Study details regarding recruitment, intervention content, program delivery, and flow of participants have been previously described.16,17 Briefly, participants (N = 307) were low-active older adults from central Illinois who were recruited to participate in a 6-month, home-based, DVD-delivered exercise program targeting FTB. Participants were randomized into 1 of 2 conditions: (1) the FTB condition in which participants were encouraged to exercise using the provided exercise DVDs or (2) an attentional control condition in which participants were encouraged to watch a DVD focusing on healthy aging (ie, Healthy Aging™ by Dr Andrew Weil). Participants in both conditions received telephone support calls from research staff at the same frequency and duration throughout the intervention (eg, biweekly calls for the first 2 mo followed by monthly calls thereafter).16 Assessments were collected at baseline and upon program completion (ie, month 6).
Measures
Depression and Anxiety.
The Hospital Anxiety and Depression Scale (HADS) was used to assess depression and anxiety symptoms.22 Participants respond on a 4-point Likert scale from 0 (most of time) to 4 (not at all). Negatively worded items are recoded, and 2 subscale scores (depression and anxiety) are computed (possible range = 0–21). Higher scores are indicative of more frequent depression and anxiety symptoms. Scores between 0 and 7 are considered normal, 8 and 10 are considered borderline abnormal, and 11 and 21 are considered abnormal per HADS subscales. The internal consistency of the HADS at baseline in the present study was adequate (α = .76 for depression and α = .80 for anxiety).
Leisure-Time Physical Activity.
The Godin Leisure-Time Exercise Questionnaire was used to assess self-reported physical activity. The Godin Leisure-Time Exercise Questionnaire assesses how many times per week an individual engages in mild, moderate, and strenuous exercise for at least 15 minutes during leisure time.23 The weekly frequencies of mild, moderate, and strenuous activities were multiplied by their respective metabolic equivalents of 3, 5, and 9 and then summed to obtain the weekly leisure-time score (possible range = 0–119).
Physical Self-Worth.
PSW was assessed using a subscale from the Physical Self-Perception Profile.24 Participants respond to each of 4 items on a 4-point Likert scale from 1 (not all true) to 4 (completely true). A sample item from this scale is “I feel confident in the physical side of myself.” The internal consistency of the Physical Self-Perception Profile in the present study was adequate (α = .86).
Statistical Analysis
Repeated-measures analyses of variance were initially conducted to determine the effects of FTB intervention compared with a control condition on depression and anxiety for the total sample (N = 307) and a subsample of participants who scored ≥8 (ie, elevated depression or anxiety symptoms25) on the HADS scales at baseline (Table 1). Cohen’s dwas calculated as an estimate of the effect sizes (0.20, small; 0.50, medium; and 0.80, large).26 Standardized residual scores were then computed for anxiety, depression, self-reported physical activity, and PSW. For the mediation analyses, we used the PROCESS macro,27 a bootstrapping statistical approach with changes in depression and anxiety as the outcome variable, changes in physical activity as the independent variable, and changes in PSW as the mediating variable. Test of the indirect effects (ie, mediation) was considered significant if the 95% confidence intervals did not include 0. Analyses initially included covariates (eg, age, sex, and education); however, they were nonsignificant and were subsequently dropped from the models. Data were analyzed in SPSS 24 (SPSS Inc, Chicago, IL).
Table 1.
Mean (SD) Values and Effect Sizes (Cohen’s d) for Total Sample and Subsample
| Baseline | Month 6 | Cohen’s d | P-value | |
|---|---|---|---|---|
| Total sample | ||||
| Depression | ||||
| FTB (n = 124) | 4.11 (3.24) | 3.51 (2.99) | 0.19 | .15 |
| Control (n = 123) | 4.15 (3.43) | 4.07 (3.27) | 0.02 | |
| Anxiety | ||||
| FTB (n = 124) | 3.80 (2.45) | 3.21 (2.18) | 0.25 | .28 |
| Control (n = 123) | 3.92 (2.96) | 3.63 (2.91) | 0.10 | |
| Subsample | ||||
| Depression | ||||
| FTB (n = 18) | 10.39 (2.03) | 5.78 (3.37) | 1.66 | .03 |
| Control (n = 24) | 10.13 (1.94) | 8.00 (3.40) | 0.77 | |
| Anxiety | ||||
| FTB (n = 10) | 9.30 (1.16) | 5.30 (1.57) | 2.90 | .30 |
| Control (n = 11) | 11.36 (3.17) | 8.91 (3.53) | 0.73 |
Note. Cohen’s d: 0.20, small; 0.50, medium; and 0.80, large.
Abbreviation: FTB, flexibility, toning, and balance.
Results
Participant Characteristics
There were no significant differences in demographic characteristics between the 2 conditions at baseline (Table 2). For the current analysis, no baseline differences were observed between the 2 conditions for depression, anxiety, physical activity, or PSW (all Ps > .19). In the depression subsample, 10 participants (FTB: n = 7 and control: n = 3) dropped out of the program due to no longer being interested (n = 5), injury unrelated to the program (n = 4), and personal issues (n = 1). In the anxiety subsample, 6 participants (FTB: n = 5 and control: n = 1) dropped out of the program due to no longer being interested (n = 3), personal issues (n = 2), and injury unrelated to the program (n = 1).
Table 2.
Participant Characteristics for FTB and Control Conditions
| Demographics | FTB (n = 158) | Control (n = 149) | FTB depression (n = 25) | Control depression (n = 27) | FTB anxiety (n = 15) | Control anxiety (n = 12) |
|---|---|---|---|---|---|---|
| Age, mean (SD), y | 70.62 (5.02) | 71.43 (5.25) | 69.73 (3.58) | 70.25 (3.72) | 69.60 (4.25) | 71.26 (4.63) |
| Sex, n (%) | ||||||
| Female | 113 (71.5) | 123 (82.6) | 21 (84.0) | 24 (88.9) | 13 (86.7) | 11 (91.7) |
| Male | 45 (28.5) | 26 (17.4) | 4 (16.0) | 3 (11.1) | 2 (13.3) | 1 (8.3) |
| Race, n (%) | ||||||
| White | 152 (96.8) | 143 (96.6) | 25 (100) | 26 (96.3) | 14 (93.3) | 11 (91.7) |
| Education, n (%) | ||||||
| Noncollege | 90 (56.9) | 82 (55) | 16 (62.0) | 17 (62.9) | 10 (66.6) | 8 (66.6) |
| graduate | ||||||
| College graduate | 68 (43.1) | 67 (44.9) | 9 (36) | 10 (37.0) | 5 (33.4) | 4 (33.4) |
| Annual income, n (%) | ||||||
| <$40,000 | 46 (29.1) | 51 (34.5) | 8 (32.0) | 10 (37.0) | 3 (20.0) | 2 (16.7) |
| ≥$40,000 | 89 (56.3) | 76 (51.4) | 12 (48.0) | 15 (55.6) | 8 (53.3) | 8 (66.7) |
Abbreviation: FTB, flexibility, toning, and balance.
Effects of FTB on Depression and Anxiety
The repeated-measures analysis of variance for the total sample had a significant time effect for anxiety (F1,255 = 10.44, P = .001, η2 = .04) in which both the FTB and control conditions decreased their anxiety. For depression, the time effect was marginally significant (F1,255 = 1.71, P = .06, η2 = .01). No time × treatment interactions were observed for depression or anxiety in the total sample. The calculated effect sizes for both subscales in the total sample revealed small effects favoring the FTB condition (Table 1).
In the subsample of participants who scored ≥8 on the HADS, the repeated-measures analyses of variance revealed significant time effects for anxiety (F1,19 = 20.25, P < .001, η2 = .52) and for depression (F1,40 = 37.88, P < .00, η2 = .49), indicating improvements in both conditions. There was also a time × treatment effect for depression (F1,40 = 5.16, P = .03, η2 = .11) in which the FTB group significantly reduced their depression levels to a greater extent than the control group (d = 1.66 vs 0.77). Although the time × treatment interaction was not significant (F1,19 = 1.17, P = .30, η2 = .06) for anxiety in the subsample, the effect sizes for the FTB condition (d = 2.90) was considerably greater than that of the control condition (d = 0.73).
Mediating Effects of PSW on the Physical Activity–Depression and Anxiety Relationship
As can be seen in Table 3, the correlations in the total sample among changes in physical activity, PSW, depression, and anxiety are all significant; thus, mediation analyses were justified. However, in the subsample of individuals with elevated depression or anxiety, although the correlations between PSW and depression and anxiety were significant, the relationship between physical activity and depression and anxiety were nonsignificant. Therefore, mediation analyses were precluded.
Table 3.
Pearson Correlations for Total Sample and Subsample
| Depression r (P-value) | Anxiety r (P-value) | Physical self-worth r (P-value) | GLTEQ r (P-value) | |
|---|---|---|---|---|
| Total sample | ||||
| Depression | .41** (.001) | −.36** (.001) | −.19** (.003) | |
| Anxiety | −.30** (.001) | −.14* (.03) | ||
| Physical self-worth | .15* (.02) | |||
| Depression subsample | ||||
| Depression | −.30 (.05) | −.16 (.47) | ||
| Physical self-worth | .02 (.88) | |||
| Anxiety subsample | ||||
| Anxiety | −.54* (.01) | .103 (.65) | ||
| Physical self-worth | −.07 (.78) |
Abbreviation: GLTEQ, Godin Leisure-Time Exercise Questionnaire.
Correlation is significant at the .05 level.
Correlation is significant at the .01 level.
Mediation analyses indicated a significant indirect effect of physical activity on depression through physical self-worth. Specifically, increased physical activity was associated with increased physical self-worth, which, in turn was associated with decreased depression (β = −0.05; 95% confidence interval, −0.11 to −0.01). However, the physical activity–depression path remained significant (β = 0.13, P = .02). Thus, this relationship was only partly mediated by PSW in the total sample (F3,235 = 15.42, P < .001, R2 = .17). For anxiety, the indirect path was significant (β = −0.04; 95% confidence interval, −0.09 to −0.01) with the physical activity–anxiety path being nonsignificant indicating full mediation through PSW.
Discussion
The purpose of this study was to determine whether a home-based, DVD-delivered exercise intervention could reduce depression and anxiety in a sample of older adults. Additionally, we examined whether increases in PSW mediated the associations between increases in physical activity and reductions in anxiety and depression. Initial analyses on the total sample indicated only a small effect on depression and anxiety driven by the FTB intervention (all ds > 0.11). However, when analyses were restricted to those participants who reported elevated depression and anxiety, the FTB condition demonstrated effects that were 2–4 times greater than the control condition. The size of these effects suggests that such a home-based exercise intervention may have a meaningful influence on depression and anxiety symptoms in older adults with elevated symptom scores. Importantly, participants with elevated depression and anxiety at baseline reported normal levels on average at the end of the intervention, whereas participants in the control condition continued to report elevated levels of anxiety and depression (Table 1).
Our findings are consistent with those of another home-based exercise intervention consisting of problem-solving treatment, social and physical activation among older adults with minor depression, which found a 50% reduction in depression symptoms in the intervention group compared with the usual care group.28 Itis worth noting that this intervention included home visits from therapists, whereas the current intervention included biweekly phone calls during the first 2 months of the intervention and monthly calls thereafter. Thus, in-person visits may not be a necessary social component of an exercise training intervention for improving depression and anxiety symptoms in older adults. Although other studies have reported that depression symptoms may remit with time, regardless of treatment(s) received,29,30 the differential patterns of symptom attenuation in the present study support a home-based, DVD-delivered exercise program as a behavioral modality for reducing depression and anxiety in older adults.
Analyses testing the mediating role played by PSW in the relationships between physical activity over time and reductions in depression and anxiety in the total sample were partially supported. In the case of depression, partial mediation was attained, as a direct path between physical activity and depression remained significant. In the case of anxiety, increases in PSW fully mediated the physical activity–depression relationship. This is encouraging, in that a home-based physical activity intervention can reduce depression and anxiety in a nonclinical sample and is supportive of other work with older adults.10 Although increases in PSW were associated with reduced depression and anxiety in the subsample, the relationships between physical activity and depression and anxiety were nonsignificant; thus, mediation analyses were not feasible. Given the size of the subsamples and the lack of statistical power, lack of conventional statistical significance is unsurprising. It is also quite possible that some of key components of the FTB intervention (eg, home-based, DVD-delivered, and phone calls) influenced participant’s perceptions of PSW independent of physical activity.30
This study had several strengths. The exercise program was a home-delivered intervention, which was able to reach a geographically diverse population across 5000 square miles of central Illinois. It was a low-cost intervention that has the potential for widespread dissemination,17 and the home-based delivery also mitigated environmental and personal barriers to exercise. Furthermore, the intervention included strength, flexibility, and balance exercises, which are fundamental to maintaining independence in old age.
Our study also had several limitations. Despite recruitment efforts, the majority of our participants were non-Latino white women, and thus, our results cannot be generalized to other populations. Future interventions may consider replicating this study among racially and ethnically diverse and underserved populations, as these populations may greatly benefit from a home-based physical activity program that addresses many barriers experienced by these populations (eg, safety, availability, cost). Additionally, we might be criticized for using self-reported physical activity rather than accelerometer-derived physical activity. Given our interest in the relationships among leisure-time physical activity and the outcomes of interest, we believe our use of the Godin Leisure-Time Exercise Questionnaire to be appropriate. Our subsample of participants who reported elevated depression and anxiety symptoms was quite small, and it is unknown if they had a clinical diagnosis of depression and anxiety; future studies may consider focusing on older clinically depressed and anxious adults to determine if the magnitude of effects is greater in home-based physical activity interventions. Other unexamined variables (eg, social support, loneliness, and medications) may have also contributed to the observed changes in depression and anxiety in the subsample.
In conclusion, the present study suggests that a home-based, DVD-delivered physical activity intervention may ameliorate depression and anxiety symptoms in older adults with elevated depression and anxiety. We also found some support for the position that changes in PSW may partially mediate reductions on anxiety and depression symptoms in older adults regardless of baseline anxiety levels.
Acknowledgments
Thanks and appreciation are extended to Ms Susan Houseworth, project coordinator for this clinical trial. The authors declared no potential conflicts of interest. This research was supported by the National Institute on Aging (grant number: 2-R01-AG20118). Trial registration: clinicaltrials.gov Identifier: NCT01030419.
Contributor Information
Susan Aguiñaga, Dept of Kinesiology & Community Health, University of Illinois at Urbana-Champaign, Urbana, IL.
Diane K. Ehlers, Dept of Exercise Science, University of South Carolina, Columbia, SC
Elizabeth A. Salerno, National Cancer Institute, Rockville, MD
Jason Fanning, Wake Forest School of Medicine, Winston-Salem, NC.
Robert W. Motl, The University of Alabama at Birmingham, Birmingham, Alabama
Edward McAuley, Dept of Kinesiology & Community Health, University of Illinois at Urbana-Champaign, Urbana, IL.
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