This systematic review protocol has been registered with the International Prospective Register of Systematic Reviews (PROSPERO; Protocol ID: CRD42020192546). Any protocol amendments will be tracked. The Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols 2015 checklist (PRISMA-P) was used to develop this protocol [12] (see Additional file 1).
Types of studies
Experimental (randomized controlled trial (RCT)) study designs that compare psychological stress levels before and after a physical activity intervention will be examined. Only original peer-reviewed published research will be included. Older studies will not be excluded. Studies written in all languages will be included.
Types of participants
Studies including older adults of any gender without severe pre-existing medical conditions that could affect their ability to perform the intervention will be included. Studies must include participants aged ≥ 50 years. If studies include multiple age groups, only data from the 50+ age group will be used for the review.
Types of interventions
This review will include physical activity interventions that include aerobic and/or anaerobic physical activity and can include individual or group-based interventions. Due to the variability of physical activity interventions, it is important that the study in question addresses the intensity—using the Copeland Threshold [13] or other similar intensity thresholds to distinguish between leisure, low, moderate, or vigorous physical activity—and duration of the intervention used. Studies that do not include measurable physical activity outcomes will be excluded.
Types of comparators
Comparator conditions will include participation in (a) a non-exercise activity or (b) no intervention.
Types of outcomes
Physical activity must only be assessed using objective methods (e.g., pedometer, accelerometer, HR monitor, V02 Max) and must not be self-reported. As it relates to stress, it is the subjective perception that will be investigated through various psychometric tests or scales (for example, the perceived stress scale (PSS) [14].
Search methods for the identification of studies
Data collection and analyses
The following databases will be searched: PubMed, Web of Science, PsycINFO, and SPORTDiscus.
Keywords will be related to stress management, older adults, and physical activity interventions. Appropriate keywords to identify studies using an experimental and randomized control study design will be employed. One example would be: “Physical activity or exercise” AND “psychological stress or distress” AND “reduc* or control or manag* or prevent*” AND “older adults or seniors or elderly or geriatric” AND “intervention”. For a study to be included, it must include an appropriate control group. References of the included studies will be searched to identify additional potentially relevant studies.
Selection of studies
Articles will be imported into Endnote software and all duplicates will be removed. Titles and abstracts will be screened for potential relevance. Full text of the relevant studies identified during previous screening will be reviewed to ensure screening inclusion criteria was met. This screening will be done by two reviewers. Any disagreements will be resolved through discussion and consultation with a third reviewer.
Data extraction
This systematic review will conform to the guidelines outlined by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist [12].
Extracted data will include information on publication (title, authors, year of publication, country of publication), population (participant sociodemographic characteristics and final sample size), intervention type and dosage, control type and dosage, mode of intervention delivery (community centre, laboratory, other setting), type of analysis, outcomes (perceived stress via survey or questionnaire, heart rate, step count, oxygen levels, time intervals, BMI), dropouts, and any adverse effects. Specific characteristics will be collated into a table for the complete review.
Assessment of risk of bias in included studies
Risk of bias (ROB) assessment will be appropriately selected depending on the design of the studies included in the final synthesis. ROB will be evaluated both within and across included studies using Cochrane’s risk of bias tool [15]. ROB will be assessed by two review authors, with discrepancies resolved by consensus with a third reviewer.
Data synthesis
A formal narrative synthesis is planned and studies that are included will be presented in summary tables with extracted data. Meta-analyses will only be performed when at least three included studies are sufficiently homogeneous in terms of study design, participants, interventions, and outcomes to provide meaningful summary measures. Effect sizes expressed as odds ratios (for categorical data) and weighted mean differences (for continuous data) and 95% confidence intervals will be used for analysis. A random-effects meta-analysis will be performed due to the likelihood of similar effect sizes, but not completely uniform throughout all studies. Heterogeneity will be assessed using the I2 statistic with values above 75% and p< 0.05 used to indicate high heterogeneity [16]. If there is high heterogeneity, a meta-analysis will not be initiated. Where a meta-analysis is not possible, a narrative synthesis will be conducted. The quality of the evidence will be assessed using the GRADE (Grading of Recommendations Assessment, Development and Evaluations) approach [17]. Finally, publication bias will be investigated by charting and deciphering the symmetry of a funnel plot for all studies considered in this review [18].
Subgroup analyses
If possible, subgroup analysis will be done to investigate if gender, BMI, or other factors play a role in stress level post-intervention.