Abstract
Introduction:
Psychological distress and depression are risk factors for cardiovascular disease (CVD). As such, a reduction in psychological distress and increase in positive well-being may be important to reduce the risk for future development of CVD. Exercise training may be a good strategy to prevent and assist in the management of psychological disorders. The psychological effects of the initial exercise sessions may be important to increase exercise adherence. The aims of this systematic review were (a) to examine whether acute aerobic, resistance, or a combination of the 2 exercises improves psychological well-being and reduces psychological distress in individuals with healthy weight and those who are overweight/obese but free from psychological disorders, and (b) if so, to examine which form of exercise might yield superior results.
Methods:
The online database PubMed was searched for articles using the PICO (patient, intervention, comparison, and outcome) framework for finding scientific journals based on key terms.
Results:
Forty-two exercise studies met the inclusion criteria. A total of 2187 participants were included (age: 18-64 years, body mass index [BMI]: 21-39 kg/m2). Only 6 studies included participants with a BMI in the overweight/obese classification. Thirty-seven studies included aerobic exercise, 2 included resistance exercise, 1 used a combination of aerobic and resistance, and 2 compared the effects of acute aerobic exercise versus the effects of acute resistance exercise. The main findings of the review were that acute aerobic exercise improves positive well-being and have the potential to reduce psychological distress and could help reduce the risks of future CVD. However, due to the limited number of studies, it is still unclear which form of exercise yields superior psychological benefits.
Conclusions:
Obese, overweight, and healthy weight individuals can exhibit psychological benefits from exercise in a single acute exercise session, and these positive benefits of exercise should be used by health professionals as a tool to increase long-term participation in exercise in these populations.
Introduction
Overweight/obesity is reaching epidemic proportions worldwide, where ~40% of the adult population are considered overweight, with 13% classed as obese. 1 In Australia, ~63% of the adult population are classified as overweight or obese (body mass index [BMI] ⩾ 25 kg/m2), and the number of people living with obesity is expected to rise given the abundance of energy-dense foods and sedentary lifestyle. 2
The prevalence of major depression in individuals who are obese is ~23%, compared with ~12% in individuals within a healthy weight range (BMI: 19-25 kg/m2). 3 In addition, individuals who are obese have an increased incidence of mental disorders compared with individuals who are non-obese. 4 The risk of psychological disorders associated with obesity is similar between men and women. 5 The relationship between obesity and psychological disorders is complex and the 2 may be connected via a vicious cycle where obesity can lead to depression, but depression may contribute to changes in lifestyle behaviours that influence body weight. 6 Psychological distress (PD) and depression are risk factors for cardiovascular disease (CVD).7–9 Exercise has been suggested as a useful tool in treating and managing depression when used in a chronic training regimen.10–13 However, as many overweight/obese individuals are not involved in exercise regularly, their experience and feelings during the first few exercise sessions are an important factor for long-term adherence.14,15
Currently, the most common treatment for depression is the use of antidepressant medication. 16 However, drug therapy is relatively expensive, some people are reluctant to use medications, and they have several side effects, including dry mouth, nausea, constipation, and insomnia.16,17 Exercise may also be used to prevent and assist in the management of psychological disorders in overweight/obese individuals. 11
There is some evidence to suggest that a single bout of exercise may improve positive well-being in individuals with major depressive disorders.18,19 State anxiety has also been reported to improve in major depressive disorders and schizophrenia after a single exercise bout.20,21
A single bout of exercise can be referred to as acute exercise. Evidence has shown that acute aerobic exercise can increase positive affect in those who are yet to develop an overt psychological disorder, but further exploration into other modes of exercise is needed. 22 Positive affect in this case is referred to as general self-reported feelings such as pleasure and tension. 22 Clinically, this is important as prevention of a chronic condition may be superior to management of the conditions from both a personal and a public health perspective.23–25 It is also clinically important to identify what type of exercise, whether it is aerobic, resistance, or a combination of the 2, is superior for improving positive psychological well-being and positive affect. In contrast, it is equally important to identify whether the exercise causes PD or self-reported stress as well as perceived fatigue, so this also can be taken into account when designing an exercise intervention. This might apply in particular to obese individuals whose exercise adherence levels are significantly low with a lack of evidence-based interventions addressing this issue. 26 The intensity of exercise must also be taken into consideration as different intensities can have varying effects on these responses.27,28
Therefore, a systematic review was undertaken (a) to examine whether acute aerobic exercise, resistance exercise, or a combination of 2 improves psychological well-being and reduces PD in individuals with healthy weight and those who are overweight/obese, and (b) if so, to examine which form, if any, of exercise might yield superior results.
Methods
Search strategy
The online database PubMed was searched for articles using the PICO (patient, intervention, comparison, and outcome) framework for finding scientific journals based on key terms. Search terms which included both full and abbreviated terms are as follows: (a) (patients) obese, overweight, adult; (b) (intervention) resistance exercise, aerobic exercise, acute, single bout; (c) (comparison) none used; and (d) (outcomes) well-being, anxiety, depression, self-efficacy, exercise perception, quality of life. Combinations of categories (a) to (c) were also used via ‘OR’ as well as ‘AND’ to combine the relevant search terms. Manual searches of reference lists in published articles meeting inclusion criteria were also used to locate other related published articles.
Inclusion and exclusion criteria
Studies which met the following criteria were included: (a) the study involved single bouts of exercise, (b) psychological attribute measured both pre- and post-exercise or compared with control, (c) participants aged 18 years or older, (d) minimum BMI of 19 kg/m2, and (e) observed some form of psychological or mood attribute using a validated questionnaire.
Exclusion criteria included the following: studies that involved a chronic exercise training protocol; age <18 years; participants with an overt cardiovascular or metabolic disease (excluding obesity); musculoskeletal, pulmonary, or neurological conditions; or studies which used animal models.
Risk of bias
Risk of bias was independently performed by 2 authors. The Cochrane Collaboration’s tool for assessing risk of bias was used to assess the methodological quality and risk of bias of the studies included in the review. Quality was determined using a descriptive component approach that included items such as the method used to allocate participants into comparable groups; blinding of participants/personnel of interventions and outcomes; outcomes measured in a standard, reliable, and valid way; completeness of outcome data for each main outcome (including attrition and exclusions from the analysis); selective reporting; and any other sources of bias. A summary of risk of bias from each study is provided in Table 1. Any disagreement or uncertainty was resolved by discussion between the 2 authors and senior group researcher to reach a consensus. Using this approach, each study was allocated a risk of bias rating.
Risk of bias.
✓ indicates ‘yes’- low risk of bias, ? indicates unclear – not enough information provided in the publication, × indicates ‘no’ – high risk of bias, n/a indicates this assessment was not applicable for this study type.
Results
In total, 424 studies matching the search criteria were identified. Of these, 386 were excluded based on title, 26 were excluded based on abstract, and 10 were duplicate articles. Manual search of reference lists of articles with appropriate inclusion criteria added 45 studies, where 4 of these were excluded due to abstract not meeting inclusion criteria. One additional study was excluded after review of the full text for not meeting the inclusion criteria. Forty-two studies were accepted for the review (Figure 1). Data from the included studies were extracted by reviewing the results section of the relevant outcome measures, and the pre-post raw data and percentage change was then calculated between 2 measures. As indicated in our risk of bias table (Table 1), only 8 of the 42 selected articles were successfully able to blind participants, personnel, and outcome assessors. This indicates a high risk of bias for most of the selected articles; however, blinding is very difficult to maintain in exercise studies.
Procedure for identifying and selecting studies related to psychological effects of single bouts of exercise.
Overall, a total of 2187 participants took part in the 42 studies. The mean age was between 18 and 64 years and the mean BMI ranged between 21 and 39 kg/m2. Only 6 studies included participants with a mean BMI in the overweight or obese classification.29–32,57,58 The specific protocols and the inclusion and exclusion criteria for each study are described in Table 2.
Protocols for Included Studies.
Abbreviations: AD ACL, Activation-Deactivation Adjective Checklist; AG-A, Affect Grid Arousal; AG-V, Affect Grid Valence; BMI, body mass index; BMI*, mean BMI determined from published mean height and weight; BMI**, mean BMI determined from published mean height and weight; and converted from imperial to metric measures; bpm, beats per minute; CS, 100% confidence scale; during-ex, during exercise; EES, Exercise Efficacy Scale; EFI, Exercise-Induced Feeling Inventory; FAS, Felt-Arousal Scale; FS, The Feeling Scale; HR, heart rate; HRmax, age-predicted heart rate maximum; HRR, heart rate reserve; IMI, Intrinsic Motivation Inventory; MCL-S1, Mood Checklist Short-form 1; M-C SDS, Marlowe-Crowne Social Desirability Scale; N/R, not reported; PACES, Physical Activity Enjoyment Scale; PANAS, Positive and Negative Affect Scale; post-ex, post-exercise; POMS, Profile of Mood States; RPE, the Borg Rating of Perceived Exertion; rpm, revolutions per minute; SAI, State Anxiety Inventory; SAM-A, Self-Assessment Manikin Arousal; SAM-V, Self-Assessment Manikin Valence; SE, standard error; SEES, Subjective Exercise Experiences Scale; SES, Self-Efficacy Scale; SF-36, 36-Item Short Form Survey; SPA, Social Physique Anxiety; SPAS, Social Physique Anxiety Scale; SSE, Specific Self-Efficacy Scales; STAI, State-Trait Anxiety Inventory; VAMS, Visual Analog Mood Scale; VO2max, maximum pulmonary oxygen uptake; VO2peak, peak pulmonary oxygen uptake
Thirty-seven studies included aerobic exercise only,28,31–49,53–55,57–70 and 2 studies included resistance exercise only.29,30 One study used a combination of aerobic and resistance exercise, 56 and 2 studies compared the effects of acute aerobic exercise versus the effects of acute resistance exercise.50,71
Aerobic exercise sessions were conducted for a total time ranging between 5 and75 minutes, at intensities varying from 50% to 85% peak heart rate (HRpeak), and one to exhaustion. 69 The exercise mode varied and included a cycle ergometer, recumbent bike, Stairmaster stepper, treadmill, and rowing ergometer (Table 2).
For resistance exercise sessions, there were some variations in the volume and intensity. One study used 2 to 3 sets of 2 to 5 repetitions at 59% 1 repetition maximum (1RM) and 1 set of 1 to 2 repetitions at 81% 1RM. 29 The other study used 3 sets of 10 repetitions at 85% to 95% 10RM. 30 Rest between sets was between 60 and 90 seconds29,30 (Table 2).
The study combining the 2 forms of exercise consisted of 10 minutes of warm-up, 20 minutes of aerobic exercise (aerobics), 20 minutes of muscle-conditioning exercise, and 10 minutes of cool-down 56 (Table 2). The intensities of the exercises were not reported; however, using the Borg Rating of Perceived Exertion (RPE) scale of 6 to 20, the median RPE for the morning aerobic exercise was 13.0 and 13.3 for evening session. The median RPE for the morning resistance exercise was 15 and 13.5 for evening session. This indicates that the exercise was of moderate intensity.
The aerobic exercise components of the 2 comparative studies consisted of 60 to 75 minutes of aerobic dance, running, or karate with intensities not reported. The resistance exercise consisted of 60 to 75 minutes of ‘body-building/weight training’, but intensities were not reported50,71 (Table 2).
Fifteen studies used the Subjective Exercise Experiences Scale (SEES),29,32,34,35,37,40,45,48,49,53,57,59,60,68,71 10 used the Exercise-Induced Feeling Inventory (EFI),31,33,36,37,39,47,61,64,65,71 and 6 used the Positive and Negative Affect Schedule (PANAS).42,54–56,62,65 Twenty-five studies used multiple psychological measurements which reported positive well-being (PWB), positive affect, PD, nega-tive affect, or fatigue28–31,33–37,39,40,42–45,47,48,54,55,64,65,67,69–71 (Table 2). Increases in PWB and positive affect are considered a positive result, whereas increases in PD, negative affect, or fatigue are negative.
Aerobic exercise
Twenty-eight studies (Table 3) reported that acute aerobic exercise increased PWB (range: 1%-67%).28,32,34–40,43–45,47,49,53,54,57–65,67,68,70 Two studies reported that aerobic exercise increased PWB in participants with ‘high self-perceived efficacy’, but one study reported PWB to be reduced in participants with ‘low self-perceived efficacy’ (34%) 33 and the other study reported an increase in those with ‘low self-perceived efficacy’. 34 In this study, self-perceived efficacy was determined prior to exercise by completing a self-efficacy scale measuring the participant’s confidence in completing 45 minutes of aerobic exercise at 70% of their maximum capacity. 33 The second study used deliberate incorrect feedback of the scores for individuals’ self-efficacy to create a ‘high self-efficacy’ and ‘low self-efficacy’ group. 34 Two studies reported PWB to decrease immediately post-exercise compared with pre-exercise.48,55 Six studies reported no changes in PWB following exercise in both healthy young and older populations.31,40,42,46,66,70
Exercise effects on psychological attributes.
Abbreviations: during-ex, during exercise; evening-ex, evening exercise; HRmax, age-predicted heart rate maximum; HRR, heart rate reserve; morning-ex, morning exercise; NA, negative affect; PA, positive affect; PD, psychological distress; post-ex, post-exercise; pre-ex, pre-exercise; PWB, positive well-being; SA, state anxiety; VAMS, Visual Analog Mood Scale; WHO, World Health Organization.
↑ indicates increased and ↓ indicates decreased.
Fifteen studies reported that acute aerobic exercise reduced PD post-exercise by 16% to 39% compared with pre-exercise.32,35,37,41–43,45,46,54,55,58,59,63,66,68 Two studies also reported PD to decrease during exercise from pre- to post-exercise,40,64 and 1 study reported a decrease immediately post-exercise versus pre-exercise compared with a control group. 49 In contrast, 4 studies reported that aerobic exercise increased PD by 20% to 37%, post-exercise versus pre-exercise.48,53,60,67 Two studies reported both an increase and a decrease in PD between multiple protocols.28,70 One study reported PD to increase compared with a control and self-selected exercise group. 62 Another study reported changes in PD following exercise were dependent on the individual perception of self-efficacy, where participants whose self-efficacy was increased reported less PD than those whose self-efficacy was reduced. 34 Four studies reported no significant changes in PD,44,57,65,69 and 1 study reported no changes in those with low initial PD. 40
The effect of aerobic exercise on perception of fatigue was variable; acute aerobic exercise decreased fatigue by 6% to 42% following exercise,32–34,37,38,40,45,48,59,67 whereas others report increases of 2% to 1.4-fold compared with baseline.31,44,47,49,53,57,60,69 One study reported perception of fatigue to decrease (26%) pre- to post-exercise compared with controls. 61 One study reported perception of fatigue to increase as exercise intensity increased, where at 50% heart rate reserve (HRR) (2%-16%) and at 80% HRR (4%-23%) fatigue increased. 60 A similar study reported perception of fatigue to decrease (36%) during a 50% HRR condition but increase (2%) during an 85% HRR condition. 36 A study also reported perception of fatigue to varying depending on intensity of exercise as well as pre-exercise levels of fatigue. 39 Five studies reported no significant change in perception of fatigue following aerobic exercise.35,46,64,66,68
Resistance exercise
Acute resistance exercise increased PWB by 3-fold in women but not in men in 1 study. 29 This study also reported that acute resistance exercise had no effect on PD, 29 whereas a second study reported an increased PD score immediately and 24 hours post-exercise (1.6- to 3.5-fold). 30
Acute resistance exercise increased fatigue 4.1-fold in individuals within a healthy weight range and 5.2-fold in individuals who were obese (BMI ⩾ 30 kg/m2) both immediately and 24 hours post-exercise. 30 Following similar intensity, type, and duration of resistance exercise, men perceive more fatigue than women. 29
Combination of exercise
A combination of aerobic and resistance exercise increased PWB (23%-48%) compared with baseline. 56 However, when aerobic exercise was compared with resistance exercise, there were no significant differences in PWB. 71 Another study also reported no significant changes in PWB. 50 A combination of aerobic and resistance exercise decreased PD by 20%. 56 Comparing aerobic exercise with resistance exercise yielded no significant changes in PD 71 ; however, another aerobic and resistance comparative study reported PD to decrease 25% in all modes of exercise compared with control. 50 One study comparing aerobic and resistance exercise reported no significant changes in fatigue, 71 whereas another reported that only resistance exercise increases perception of fatigue (74%). 50
Discussion
We report that acute aerobic exercise (a) improves PWB and has the potential to reduce PD in healthy weight individuals but may increase PD in obese individuals, whereas (b) the effects of aerobic and resistance exercise on the perception of fatigue are still unclear. It should also be acknowledged that 2 of the 42 studies reported a decrease in PWB after acute aerobic exercise. Each form of exercise may be beneficial, but with the current limited data, it remains unclear whether there is a difference between exercise modes.
Aerobic exercise
Positive well-being can be defined as the degree to which individuals are psychologically fully functioning or realizing their full potential. 72 It appears that the change (increase or decrease) in PWB following aerobic exercise depends on the individual’s self-perceived efficacy. Those who have high self-efficacy prior to exercise are more likely to benefit with increases in PWB, but those with low in self-efficacy may feel less positive following exercise.33,34 Changes in self-efficacy during exercise may be linked to PWB changes, as it was reported to increase post-exercise which was reflective of increases in PWB. These findings are similar to previous research investigating the effects of acute aerobic exercise on participants who are diagnosed with psychological disorders such as depression, schizophrenia, and anxiety.18–21 These findings have implications for clinical exercise practice as it indicates that the individual’s perception or feelings prior to exercise may determine to what degree they will enjoy the exercise and, in turn, affect long-term adherence to exercise. Furthermore, this should be taken into consideration when prescribing exercise to those with low self-efficacy to reduce the likelihood of dropout. Our review showed that acute aerobic exercise improves PWB in individuals who are within the healthy weight range. This finding has clinical importance as using non-pharmaceutical options could be an alternative approach to improve PWB in any population but may also be applied to those who are obese and those who live with psychological disorders. The exercise alternative may be an option for those who are reluctant to use medication.
Psychological distress is often described as a blanket term referring to feelings such as anxiety, depression, and stress-related emotions. 51 Those with both depressive and anxious distress symptoms have been shown to have an increased risk of developing CVD. 73 Aerobic exercise has the capacity to reduce PD in those with a healthy body weight but may increase in those who are obese. These findings are similar to research that has been conducted on acute exercise in those with psychological disorders including depression, anxiety, and schizophrenia.19,21 This finding highlights that even a single bout of aerobic exercise could help in reducing PD and possibly affecting the chance of psychological complications arising. On the contrary, 5 studies found that PD had increased compared with baseline levels.34,48,53,60,67 The different findings between the studies that reported reduced PD and increased PD following exercise can possibly be explained by the fact that participants who reported reduced PD had been physically active recently, whereas most of those who reported PD to increase had not been recently active, which may include individuals who are obese. Further studies should be conducted to determine whether this factor can affect the outcome of PD, and if not, then whether acute exercise is more likely to increase or decrease PD.
The definition of fatigue is still widely unclear in the research field as it currently has no known biological markers to be measured. 52 However, for the purpose of this review, fatigue was referred to as having feelings of a decreased capacity to complete both physical and mental activities. 74 The scales used for fatigue, such as the SEES and EFI, both have a subscale that observes fatigue or physical exhaustion.51,75 Acute aerobic exercise decreased perceived fatigue in 10 studies we reviewed. One of these reported that fatigue was significantly reduced following exercise but only in individuals with high self-efficacy prior to exercise. 34 Similar to the results for PWB, it may indicate that self-efficacy is a key factor in helping improve psychological attributes in acute exercise. Clinically, if exercise is to reduce the perception of fatigue, it can be beneficial as it will allow individuals to maintain an active lifestyle. However, others reported that fatigue increased compared with baseline.31,44,47,49,53,57,60,69 The difference in findings between studies who reported fatigue to increase and decrease could be explained by (a) some of the studies that reported an increase in fatigue used participants who were inactive recently and (b) large variations in exercise modes between each study. Along with these, it may be expected that fatigue will occur as a result of a single bout of exercise, where a chronic training program could help reduce fatigue over a longer period of time. 76 The time when fatigue levels are reported could also have an impact on the results. Further research using similar populations and equipment could provide more consistent results for the effect of acute aerobic exercise on fatigue.
Acute aerobic exercise has been shown to improve PWB; however, its effects on PD and perceived fatigue are variable. In circumstances where medication is contraindicated or proving to be ineffective, acute aerobic exercise could be used to complement or further improve treatment results. However, there is some evidence indicating that exercise may not be superior and warrants the need for further research in this area to clarify. 77 Acute aerobic exercise has also been shown to negatively affect PD and fatigue in some cases. Further research should be conducted to clarify the effect acute aerobic exercise has on these psychological attributes, especially PD and perceived fatigue.
Resistance exercise
To date, there are very limited data examining the effects of acute resistance exercise on psychological parameters. In women, but not men, PWB appears to increase following acute resistance exercise. 29 In contrast, perception of fatigue was higher in men than women. However, because only 1 study identified reported PWB, the effect of acute resistance exercise, including mode and intensity, is largely unknown. Resistance exercise may yield psychological benefits and may be a good complementary mode of exercise to aerobic exercise, especially in those who hold it as a higher preference. Further studies are needed to test this hypothesis.
The effect of acute resistance exercise on PD is not clear as there are only 2 studies with conflicting results in individuals who have a healthy weight and are obese.29,30 As with PWB, the lack of studies reporting acute resistance exercise inhibits the capacity to compare it with acute aerobic exercise.
Resistance exercise increased fatigue in men, 29 whereas another study reported very large increases in fatigue in both men and women who are of normal weight and obese. 30 These findings were valuable to this review as they included both non-obese and obese individuals.
The effect acute resistance exercise had on PWB was positive, but unfortunately it was only measured in one of the 2 studies and only in women. Therefore, the positive effect may not be a true indicator of how acute resistance exercise affects PWB. The effect on PD and perceived fatigue was disputed, but as for PWB may not provide a clear insight as to the true effects acute resistance exercise produces due to the lack of literature.
Combination of exercise
The study that combined acute aerobic and resistance exercise reported that PWB had increased compared with baseline. 56 This finding is promising but not sufficient to make a definitive conclusion regarding the effect of combined exercise versus each type of exercise separately. Further research is required to determine which type of exercise provides superior results in changing PWB.
The effect of a combination of exercise on PD is unclear. The results of the 2 studies included were varied and reported change between different intervention groups. These results provide little insight as to which mode is superior, due to the lack of studies to compare with, just as in the combination exercise study. Further investigation into why these studies are not as common as aerobic or resistance exercise might also be beneficial to help determine the ideal mode of exercise to reduce PD.
The effect of a combination of exercise on fatigue is also still unclear. Only the comparative acute exercise studies reported fatigue, and these found that it had increased when comparing 2 different types of aerobic exercise, as well as after a bout of resistance exercise, but there was no difference between aerobic and resistance exercise.50,71 This further outlines the lack of literature in this mode of exercise and requires further research to help gain more clarity when determining the better mode of exercise to help reduce fatigue.
A combination of acute aerobic and resistance exercise was reported to increase PWB but decrease PD only at a certain time point. 56 A comparative acute aerobic and resistance exercise study reported no change in PWB, increases in PD, and perceived fatigue between different types of aerobic exercise only. 71 The lack of literature using these 2 types of acute exercise inhibits the ability to confidently determine whether aerobic, resistance, or a combination of exercise is most beneficial; hence, no difference in exercise modes appears to exist. The individual’s preference on mode of exercise could also have an impact on the outcome of the psychological responses, as well as differences in their performance compared with their personal expectations during the exercise. Further research would be appropriate to help understand which would be best to apply to achieve the best outcome for all patients.
A limitation of this study is the relative small number of studies that examined the effect of acute resistance and combined exercise on psychological parameters. Reporting results from a small amount of studies may not provide significant evidence to be used in practice, but is a first step towards clarifying future research needs. Most of the papers were classed as high risk for participant, personnel, and outcome assessor bias; however, it should be acknowledged that it is very difficult to blind in exercise studies. This review could be used as a stepping stone for future researchers to begin filling the gaps in literature. Six studies only used participants who are overweight/obese (BMI ⩾ 25 kg/m2), and only 2 of those used obese individuals (BMI ⩾ 30 kg/m2).29,30 Nevertheless, we identified that current evidence indicates that acute aerobic exercise can lead to a higher perception of PWB in individuals free from psychological disorders. The evidence indicates variability regarding the effect of acute aerobic exercise on PD, providing indications for further research in this area. Individuals who are obese, and those with healthy weight, can exhibit psychological benefits from exercise from a single exercise session, and these positive benefits of exercise can be used by physical activity and health professionals as a tool to increase long-term participation in exercise in these populations. As low PWB and increased PD have been indicated as risk factors for CVD, acute exercise is important in the prevention of developing CVD.
We report that acute aerobic (a) improves PWB and also has the potential to reduce PD in normal weight individuals but may increase PD in obese individuals, and (b) the effects of aerobic and resistance exercise on the perception of fatigue, as well as which form of exercise yield superior psychological benefits, are currently unclear.
Footnotes
Peer review:
Five peer reviewers contributed to the peer review report. Reviewers’ reports totalled 1355 words, excluding any confidential comments to the academic editor.
Funding:
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: I.L. is supported by Future Leader Fellowship (ID: 100040) from the National Heart Foundation of Australia.
Declaration of conflicting interests:
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Author Contributions
Conceived and designed: TE, SC, ARN, IL. Analyzed the data: TE, SC, IL. Wrote the first draft of the manuscript: TE. Contributed to the writing of the manuscript: All authors. Agree with manuscript results and conclusions: All authors. Jointly developed the structure and arguments for the paper: All authors. Made critical revisions and approved final version: All authors.