Longitudinal Effects of Supported Exercise on Elevated Anxiety and Depression Scores in Formerly Sedentary Adults With Severe Obesity

Abstract

Persistent anxiety and depression may be particularly high in individuals with obesity. Increasing exercise reliably improves mood in the general population; however, it has rarely been tested specifically in adults with severe obesity. Volunteer participants (60% women) of a theory-based cognitive-behavioral weight-management treatment with severe obesity and elevated (highest 10% based on normative values) depression (N = 89) or anxiety (N = 60) were assessed at baseline and Month 6 on measures of exercise output (overall, and whether the equivalent of three moderate sessions/week [i.e., ≥ 15 METs/week] were completed), corresponding mood, and exercise barriers self-efficacy. There were significant improvements (large effect sizes) in exercise outputs and mood. Increase in exercise outputs was significantly associated with reduced depression (β = −.52) and anxiety (β = −.67) scores. At least 15 METs/week of exercise was reached by 61% and 60% of participants, respectively. Participants demonstrated significantly greater reductions in depression and anxiety scores over 6 months than those completing lower amounts. Change in exercise barriers self-efficacy significantly mediated the following: (a) the prediction of depression change by change in exercise output and (b) the prediction of change in anxiety by completion/non-completion of ≥ 15 METs/week of exercise. Findings suggest substantial benefits for depression and anxiety in adults with severe obesity under conditions of moderate exercise supported by a community-based cognitive-behavioral treatment. Because of its identified mediation properties, future behavioral treatments should seek to increase barriers self-efficacy to maximize effects on elevated depression and anxiety and possibly weight.

Keywords

obesity mood depression anxiety exercise

The prevalence of a persistent anxiety or depressive disorder in the United States general population was estimated to be approximately 5% (Young et al., 2008). Positive effects of exercise on anxiety, depression, and mental health was consistently found in research (Arent et al., 2020; Wegner et al., 2014), although results were often based on the following: (a) inadequate measurements of exercise and mood, (b) samples combining individuals within both normal and abnormal ranges of anxiety and/or depression, (c) mixed accounting of participant characteristics, and (d) varied study durations (Baillot et al., 2018; Carraça et al., 2021; Hu et al., 2020). Reductions in depression and anxiety were most pronounced when they were initially above normal ranges (Wegner et al., 2014).

Neurobiological explanations of the relationship between exercise and mood changes have been suggested (e.g., influences on synaptic plasticity and modulation of norepinephrine content; Dishman et al., 2006). However, the lack of a clear exercise dose-mood change relationship prompted some researchers to suggest that, rather than such biological explanations, feelings associated with use of one’s internal resources to self-regulate through lifestyle barriers (yielding feelings of mastery and ability, or barriers self-efficacy; Bandura, 1997) largely impact the effects of exercise on mood (Annesi, 2005, 2012; Arent et al., 2020; White et al., 2009). Some research suggested that the equivalent of three moderate exercise sessions per week induces significant improvements in mood, with little additional benefit in mood change associated with greater amounts (Annesi, 2012). Although untested, this might be especially true in the case of individuals with obesity who often experience the most challenge adhering to a program of even moderate amounts of exercise (Trost et al., 2002).

Social cognitive theory (Bandura, 1986) and self-efficacy theory (Bandura, 1997) also suggest that feelings of accomplishment and self-efficacy associated with persevering with such an important behavior as physical exercise will benefit one’s enduring psychological disposition (Baker & Brownell, 2000; Bandura, 2005; Totawar & Nanbudiri, 2014). Thus, it is possible that self-efficacy associated with newly established exercise will foster improved mood within a weight-loss treatment context through what Baker and Brownell (2000, p. 320) referred to as “a healthier psychological climate in which individuals have more cognitive and emotional resources” (p. 320). Hence, self-efficacy might mediate relationships between exercise and mood changes, especially in the presence of behavioral weight-management interventions (Olander et al., 2013).

With few notable exceptions (e.g., Babyak et al., 2000), however, research has addressed the shorter term (acute) effects of exercise on mood, and many investigations have been compromised by study designs in which participants understood that improved mood was a treatment goal (e.g., Arent et al., 2020; Dishman et al., 2006). Thus, it was unclear what portion of the observed changes was due to artifacts related to participants’ expectations (e.g., priming effects, Hawthorne effect; Klein et al., 2012), and exercise-associated changes in persistent or chronic depression and anxiety remained largely unaddressed. Also, even though severe obesity is a factor associated with adverse mood (de Wit et al., 2010; Dixon et al., 2003; Roberts et al., 2003; Simon et al., 2006) that might particularly impact the effects of exercise (Dunn et al., 2005), related research has rarely addressed that subsample specifically.

Medical professionals have appeared cautious about suggesting exercise for individuals with anxiety and depression issues (CME Institute of Physicians, 2008), especially for those with severe obesity who are the most challenged with adherence (Burgess et al., 2017; Trost et al., 2002). Thus, findings are needed to clarify those associations to inform future clinical applications. These might extend to treatments focused on weight loss in which both exercise and mood-related factors are paramount (Annesi, 2012, 2020; Palmeira et al., 2010). Thus, the present research was conducted with adults with severe obesity and elevated depression and anxiety within a cognitive-behavioral intervention setting. The treatment focus was to target exercise and weight loss rather than mood change to minimize problematic expectation effects. It was predicted that there would be significant 6-month improvements in exercise outputs, depression and anxiety scores, and exercise barriers self-efficacy. It was further hypothesized that an increase in exercise would be significantly associated with decreases in depression and anxiety, and a change in barriers self-efficacy would significantly mediate those relationships. A community-based treatment setting was purposefully selected for this research because it was amenable to referrals by medical professionals if findings so indicated.

Method

Participants

Through print and electronic communications, adults of at least 21 years were asked of their interest to volunteer for a program supporting exercise and healthy eating for weight loss. The present data were part of a larger research program on the behavioral treatment of obesity that remains in data collection. For this investigation, additional inclusion criteria were body mass index (BMI) ≥ 35.0 kg/m² (Class 2 and 3 obesity), self-reported current exercise of ≤ 2 moderate sessions/week, written clearance to participate from a medical professional, and an elevated depression and/or anxiety score (defined here as ≥ 1.5 SD above the sex-adjusted normative mean across adults [highest ∼ 10%] using the Profile of Mood States-Brief Form; McNair & Heuchert, 2009). If prescribed psychotropic medications, change in those medications (including dosages) from 6 months prior to the end of the study period was reason for exclusion because it could affect the measurements of mood. There were 115 participants who met the above criteria for either elevated depression or anxiety. Eighty-nine participants (54 women; M_age = 42.8 years, SD = 9.6; M_BMI = 41.4 kg/m², SD = 6.2) and 60 participants (36 women; M_age = 43.5 years, SD = 9.5; M_BMI = 40.1 kg/m², SD = 6.0) had elevated depression and anxiety, respectively. Thirty-four participants (30%) had both elevated depression and elevated anxiety. In the elevated depression and anxiety groups, participants were either White (61% and 60%, respectively) or Black (39% and 40%, respectively). Nearly all reported a middle-class yearly household income of $35,000–$70,000. The research protocol and written consent required from each participant prior to study start were approved by a university institutional review board. Ethical standards indicated by the American Psychological Association and the Helsinki Declaration were followed throughout.

Measures

Exercise output was measured by the Godin Leisure-Time Physical Activity Questionnaire (Godin, 2011). Within that instrument, the metric of metabolic equivalent (1 MET = 3.5 mL of O₂/kg/min) per week was determined by the respondent’s reported number of exercise sessions of ≥ 15 min at an intensity ranging from 3 METs (e.g., easy walking) to 9 METs (e.g., running), which were summed. A MET score of 5 was considered a moderate session of exercise. Concurrent validity was indicated through reported correspondences with treadmill test and accelerometer scores (Jacobs et al., 1993; Pereira et al., 1997). Test–retest reliability over 2 weeks was reported as .74 (Pereira et al., 1997).

Depression and anxiety were measured by scales of the Profile of Mood States-Brief Form (Shelly L. Curran, Michael A. Andrykowski, Jamie L. Studts). Each of their five items such as “sad” and “nervous,” respectively, required responses from 0 (not at all) to 4 (extremely), which reflected feelings over the previous two weeks. Responses were summed to yield separate depression and anxiety scale scores. Internal consistencies for both men and women were reported to range from α = .90–.95. Test–retest reliabilities over three weeks were .70–.74 (McNair & Heuchert, 2009). For the present samples, Cronbach’s αs were .84 (depression) and .86 (anxiety). In previous research, concurrent validity was indicated through correspondences with well-accepted and lengthier measures of depression and anxiety such as the Beck Depression Inventory (BDI) and State-Trait Anxiety (STA) Inventory (McNair & Heuchert, 2009; Rossi & Pourtois, 2012). The Profile of Mood States has been extensively used in research assessing exercise-associated changes in chronic mood (Berger & Motl, 2000).

Exercise barriers self-efficacy, or the confidence one has in using internal resources to overcome barriers and difficulties to successfully completing exercise behaviors (Bandura, 1997), was measured by the Exercise Self-Efficacy Scale (Marcus et al., 1992). Its five items such as, “How confident are you that you can persist with exercising when you are tired?,” required responses from 1 (not at all confident) to 11 (very confident), which were summed. Internal consistencies were reported to range from Cronbach’s α = .76–.82, and test–retest reliabilities over 2 weeks were reported as .74–.78 (Marcus et al., 1992). For the present sample, Cronbach’s α = .81.

Procedure

The study was conducted within community wellness settings in the United States. Wellness leaders employed at those facilities were trained in and administered an exercise support treatment based on a previously developed protocol focused on increasing adherence to regular exercise (Annesi et al., 2011). It emphasized the development of participant-set long- and short-term goals and training in self-regulatory skills to overcome barriers to exercise (e.g., relapse prevention and cognitive restructuring). The cognitive-behavioral protocol was based on tenets of self-efficacy theory (Bandura, 1997) and social cognitive theory (Bandura, 1986). Exercise plans were based on each participant’s tolerance and preferences and emphasized cardiovascular activities (as opposed to resistance training and/or flexibility exercises). There were six one-on-one exercise-support meetings of 30–40 min each occurring from baseline through month six. No exercise was conducted during these office-based meetings. A manual-supported group nutrition component (Brownell, 2004; Kaiser Permanente, 2008) was led every two weeks by registered dietitians beginning six weeks after study start (six sessions in total). Study staff administered the study measures in a private area at baseline and month six. Their random fidelity checks of approximately 15% of sessions indicated adequate protocol compliance.

Data Analyses

Based on established criteria (White et al., 2011), the 16% of missing cases were deemed missing-at-random, so the expectation maximization algorithm (Schafer & Graham, 2002) was used for their imputation and to facilitate an intention-to-treat study format (Gupta, 2011). For the primary regression analyses, 54 participants per analysis were required to detect a moderate effect (f² = .15) at the statistical power of .80 (α ≤ .05) (Cohen et al., 2003).

Dependent t tests first separately assessed score changes from baseline to month six on exercise output, mood, and exercise barriers self-efficacy in the elevated depression and elevated anxiety samples. Effect sizes were expressed as Cohen’s d ([M_{Month 6}−M_baseline]/SD_baseline), where 0.20, 0.50, and 0.80 are considered small, moderate, and large effects, respectively (Cohen, 1992). Next, within those groups, bivariate regression analyses assessed relationships between changes in exercise output and either depression or anxiety changes (based on group). Because floor or ceiling effects were not observed, consistent with suggestions (Glymour et al., 2005), gain scores (i.e., changes from baseline to month six) were unadjusted for their baseline value.

Then, based on a previously proposed cut-point of exercise for significant mood change to occur (Annesi, 2005), and through use of the Godin Leisure-Time Physical Activity Questionnaire (Godin, 2011) for measurement, participants were coded as completing either the equivalent of three moderate sessions/week or more (i.e., ≥ 15 METs/week) at month six (dummy code = 1) or completing less than that amount (dummy code = 0). Following this, mixed model repeated-measures ANOVAs assessed respective differences in depression and anxiety score changes, by group (≥15 METs/week vs. < 15 METs/week). Effect sizes were expressed as partial eta-squared (η_p² = SS_Effect/[SS_Effect + SS_Error]), where 0.01, 0.09, and 0.25 are considered small, moderate, and large effects, respectively (Cohen, 1992).

Finally, a series of mediation models were fit to assess if change in exercise barriers self-efficacy significantly mediated relationships between the two measures of exercise output and depression and anxiety score changes. Significance of mediation was reported through 95% confidence intervals (95% CI, percentile bootstrap method; Hayes, 2018) where statistical significance was designated when 0 was not present between its lower and upper limits. Paths a, b, and c^′ of the corresponding models are reported in Figures 1 and 2 as unadjusted Beta (B) and its corresponding standard error (SE_B) and p value. Overall, model R²s are also reported.

Figure 1.

Mediation of the relationship between changes in exercise output and depression by exercise barriers self-efficacy change. Note. Path a, independent variable→mediator. Path b, mediator→dependent variable. Path c^′, independent variable→dependent variable, controlling for the mediator (Path a × Path b). *p ≤ .05. **p ≤ .01. ***p ≤ .001. (a) ΔExercise as the independent variable. (b) ≥15 METs/week as the independent variable.

Figure 2.

Mediation of the relationship between changes in exercise output and anxiety by exercise barriers self-efficacy change. Note. Path a, independent variable→mediator. Path b, mediator→dependent variable. Path c^′, independent variable→dependent variable, controlling for the mediator (Path a × Path b). *p ≤ .05. **p ≤ .01. ***p ≤ .001. (a) ΔExercise as the independent variable. (b) ≥15 METs/week as the independent variable.

Because it was possible that degree of success with weight loss could affect the prediction of change in mood (Palmeira et al., 2010), change in weight (measured by study staff using a recently calibrated digital floor scale; Health-o-meter Model 800KL, McCook, IL) was controlled in the regression analyses. Statistical significance was set at α ≤ .05, two-tailed, throughout. SPSS Statistics Version 26 (IBM, Armonk, NY), integrating the PROCESS macro-instructional software Version 3.5 Model 4 with 20,000 bootstrapped resamples (Hayes, 2018), was used for the statistical analyses.

Results

Within-Group Changes

For both the elevated depression and elevated anxiety score participants, there were significant improvements from baseline to month six on exercise outputs and their corresponding mood (large effect sizes), where mean increases in exercise barriers self-efficacy did not reach statistical significance (small effect sizes) (Table 1). In the 34 participants with both elevated depression and anxiety, their effect sizes for change (d = 1.24 and 1.57, respectively) were similar to those of the overall groups. Of the 89 and 60 participants with elevated depression and anxiety, respectively, 28 (31.5%) and 21 (35.0%) shifted into a “normal” range (i.e., ±0.5 SD around the sex-adjusted normative mean; McNair & Heuchert, 2009) at month six.

Table 1.

Changes in Study Variables from Baseline to Month 6.

	Baseline		Month 6		Score change		t	df	p	95% CI	d
	M	SD	M	SD	M	SD
Elevated depression participants (N = 89)
Exercise output (METs/week)	8.71	10.24	23.19	19.70	14.48	17.96	7.61	88	<.001	10.69, 18.26	1.41
Depression	10.15	2.88	6.85	4.25	−3.29	4.10	7.58	88	<.001	−4.15, −2.43	1.14
Exercise barriers self-efficacy	28.28	11.30	29.61	11.41	1.33	9.56	1.31	88	.194	−0.69, 3.34	0.12
Elevated anxiety participants (N = 60)
Exercise output (METs/week)	7.32	8.88	19.85	17.35	12.53	16.17	6.01	59	<.001	8.36, 16.71	1.72
Anxiety	11.12	1.98	8.00	4.42	−3.12	3.67	6.58	59	<.001	−4.06, −2.17	1.58
Exercise barriers self-efficacy	28.88	12.19	31.08	11.25	2.20	9.50	1.79	59	.078	−0.25, 4.65	0.18

Note. Score change represented change from baseline to Month 6. t tests are two-tailed. 95% CI, 95% confidence interval. d, Cohen’s measure of effect size ([M_{Month 6}−M_baseline]/SD_baseline).

Prediction of Mood Change by Exercise Output

In the elevated depression participants, increase in exercise significantly predicted reduction in depression scores, B = −0.12, SE_B = 0.02, β = −.52, p < .001. In the elevated anxiety participants, increase in exercise significantly predicted reduction in anxiety scores, B = −0.15, SE_B = 0.02, β=−.67, p < .001. Consistent with most related research (e.g., Dombrowski et al., 2014; Loveman et al., 2011), weight change varied greatly across participants (elevated depression group range = −16.22 kg to 7.15 kg; M = −2.92 kg, SD = 4.69; elevated anxiety group range = −13.43 kg to 5.00 kg; M = −2.53 kg, SD = 3.90). Because those data did not significantly add to the explained variances in any regression model, they were removed from further analyses.

Effects of 15 METs (∼3 Moderate Exercise Sessions) Per Week Minimum

For the elevated depression and elevated anxiety participants, there were no significant differences at baseline (on depression, age, sex, or ethnicity [ps > .390], or anxiety, age, sex, or ethnicity [ps > .490], respectively) between those who completed ≥15 METs of exercise/week at Month 6 (61% and 60%, respectively) and those who completed less. For the participants with elevated depression, depression scores were significantly reduced overall, F (1, 87) = 56.32, p < .001, η_p² = 0.39. Time × group analysis indicated that depression reductions were significantly greater for the ≥ 15 METs/week group, F (1, 87) = 37.55, p < .001, η_p² = 0.30. For those with elevated anxiety, anxiety scores were significantly lowered overall, F (1, 58) = 48.54, p < .001, η_p² = 0.46. Time × group analysis indicated that reductions in anxiety were significantly more pronounced for the ≥15 METs/week group, F (1, 58) = 37.11, p < .001, η_p² = 0.39. Descriptive statistics are given in Table 1.

Mediation by Exercise Barriers Self-Efficacy

Change in exercise barriers self-efficacy significantly mediated the prediction of depression change, by change in exercise output, B = −0.01, SE_B = 0.01, 95% CI [−0.03, 0.00] (Figure 1(a)); Model R² = .32, F (2, 86) = 20.09, p < .001. When the occurrence of ≥ 15 METs/week was substituted as the independent variable, exercise barriers self-efficacy did not demonstrate significant mediation, B = −0.25, SE_B = 0.24, 95% CI [−0.80, 0.15] (Figure 1(b)); Model R² = .38, F (2, 86) = 26.67, p < .001.

Change in exercise barriers self-efficacy did not significantly mediate the prediction of anxiety change, by change in exercise output, B = −0.01, SE_B = 0.01, 95% CI [−0.03, 0.01] (Figure 2(a)); Model R² = .32, F (2, 57) = 25.67, p < .001. When completion of ≥ 15 METs/week was substituted as the independent variable, exercise barriers self-efficacy demonstrated significant mediation, B = −0.35, SE_B = 0.20, 95% CI [−0.81, −0.02] (Figure 2(b)); Model R² = .43, F (2, 57) = 21.66, p < .001.

Discussion

Consistent with expectations, the present cognitive-behavioral treatment was associated with significant improvements in exercise outputs, depression, and anxiety in the present sample of adults with severe obesity, low physical activity, and elevated depression or anxiety scores. However, replications with a control condition will be required to increase confidence in those findings and to better-enable attribution of the observed changes in the psychological factors to the treatment or exercise itself. Although the increase in exercise barriers self-efficacy did not reach statistical significance, it significantly mediated inverse relationships between changes in exercise outputs and depression and anxiety scores. For depression change, significant mediation occurred when exercise change was treated as a continuous measure, and for anxiety change when exercise output was viewed as a dichotomous measure (i.e., ≥3 moderate exercise session/week or less). Those findings are supported by previous research with adults averaging 30–35 years-of-age, indicating that significant reductions in chronic depression require slightly more exercise than improvements in anxiety levels (Annesi, 2003). The results indicated that barriers self-efficacy is an important mechanism of the relationship between exercise and reductions in depression and anxiety, even when exercise outputs increase to levels below the 5–7 days/week of moderate exercise typically recommended for physical health benefits (Piercy et al., 2018). They also counter purely neurobiological explanations of the exercise-mood change relationship.

Strengths of this study include evaluation of a sample with reduced expectations of mood improvements, assessments of longitudinal effects, and the inclusion of participants with pathologies that might specifically benefit from improvements in the targeted variables. Thus, it addressed previously suggests gaps in the related research with adults with obesity (Baillot et al., 2018). Some limitations were a volunteer sample that might have been especially motivated, measurement of exercise outputs via self-report rather than a more objective method (e.g., accelerometry), and a time frame that requires extension within replications to meaningfully evaluate effects on long-term weight change. Also, more extensive follow-up on missing data might be constructive in the future to determine, for example, if exercise-related injury is a problem for the present sample type. Although inclusion of a control condition would have also been beneficial, improvements in mood associated with exercise have previously been supported when contrasted with changes associated with simply the passage of time or similar degrees of attention (Annesi, 2003, 2012; Arent et al., 2020; Dunn et al., 2005).

Overall, findings suggest that medical professionals should incorporate moderate exercise for adults with elevated depression and anxiety, even when they have severe obesity, when deemed clinically safe. Because of the indicated behavioral mechanisms of change, community-based programs might provide sufficient ongoing support to empower the self-regulatory skill and self-efficacy increases needed for maintained exercise. Improvements in self-regulation and self-efficacy have also been identified as a prerequisite for long-term success with weight loss (Annesi, 2020).

Footnotes

Acknowledgments

Study participants and practitioners are acknowledged for their participation in the research.

Declaration of Conflicting Interests

The author declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author received no financial support for the research, authorship, and/or publication of this article.

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