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Trial registered on ANZCTR


Registration number
ACTRN12619001726145
Ethics application status
Approved
Date submitted
1/12/2019
Date registered
9/12/2019
Date last updated
9/12/2019
Date data sharing statement initially provided
9/12/2019
Date results information initially provided
9/12/2019
Type of registration
Retrospectively registered

Titles & IDs
Public title
The Effects of a 16-week Aerobic Exercise and Mindfulness-based Intervention on Chronic Psychosocial Stress: A Nonrandomized Pilot and Feasibility Trial
Scientific title
The Effects of a 16-week Aerobic Exercise and Mindfulness-based Intervention on Chronic Psychosocial Stress in a Non-clinical Sample of Healthy Adults: A Nonrandomized Pilot and Feasibility Trial
Secondary ID [1] 299877 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Chronic psychosocial stress 315288 0
Condition category
Condition code
Mental Health 313588 313588 0 0
Other mental health disorders
Mental Health 313589 313589 0 0
Anxiety

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Intervention Overview

This nonrandomized pilot and feasibility trial was conducted as a single-arm trial where all participants were subjected to 16 weeks of aerobic exercise and mindfulness-based training, delivered concurrently. This trial was conducted across two waves: wave 1 (August to November 2016) and wave 2 (April to July 2017). Recruitment was conducted across a one-month time period prior to the trial period of each wave. Pre-test (T0) and post-test (T1) measures were obtained 1 to 4 weeks prior to and after the trial period. As participants were predominantly postgraduate and undergraduate students from a variety of disciplines, these periods were selected to correspond to 'low-stress' periods in the academic calendar (i.e., pre- or -post semester). Participant compliance to the intervention was encouraged in weekly meeting sessions and via weekly email progress reports.

Mindfulness-based Intervention (MBI)

The MBI was an adaptation of the mindfulness-based Stress Release Program (SRP): a stress management and cognitive therapy program that uses mindfulness practices to raise awareness of the processes underlying stress and negative emotions. The training approach can be summarized in two modules that align with the monitor and acceptance theory (MAT) of mindfulness meditation. This includes: (1) attention monitoring, and (2) acceptance. One instructor who had received direct training from the original facilitators of SRP delivered the intervention.

Attention monitoring: The goal of the attention monitoring module was to systematically train participants to improve their ability to observe present-moment experiences through formal meditation practices. The formal practice of meditation involved activities that required sustained focused-attention meditation towards a focus object (i.e., breath, body, sound, or thoughts). The formal practice prescription comprised up to 20 min of focused-attention meditation, daily, over 16 weeks. Completion of this daily target was at the discretion of participants. Formal practice was conducted in a group setting in a seminar room located at Monash University during the weekly training session, and participants were provided with audio recordings containing spoken instructions (Monash University Counselling Services) to guide home practice. To guide progress and track compliance, participants were further instructed to record their formal practice in an online spreadsheet (Google Sheets, Google, US). Formal practice was reported each day as minutes of formal meditation practice. This was converted to hours, and total hours of meditation for each participant across the intervention was recorded as the formal practice dosage. Adherence requirements for the attention monitoring module were completion of at least 50% of the target formal meditation (target = 37.34 h [20 min/day over 16-weeks]; minimum adherence requirement = 18.67 h).

Acceptance: The goal of the acceptance module was to foster a mental attitude of acceptance towards negative and stress-laden experiences. This included: (1) a willingness to allow negative experiences to rise and pass, and to let go of thoughts, ideas, or desires that may be associated with the experience (non-attachment), (2) a willingness to be available to negative experiences without attempting to suppress or avoid them (non-avoidance), and (3) a conscious abstention for categorizing an experience as good or bad, or right or wrong (non-judgment). These skills were trained over eight weekly group training sessions and discussion activities (50 min), and homework tasks (completed at discretion of participants) that encouraged participants to reflect on stress-laden or negative experiences with an attitude of acceptance. Adherence requirements for the acceptance module were that participants attend at least 50% of the group psychoeducation sessions, with compliance monitored through attendance records.

Aerobic exercise training intervention (AET)

The AET program comprised endurance running as part of a half-marathon training program. The AET prescription was three runs per week over 16 weeks (one group session and two self-guided sessions). This included: (1) a 5 min warm up, then an interval run that involved 200 m bursts of near-maximal intensity followed by a 200 m recovery to the total of 16 min, then a 5 min cool down, (2) a short run of moderate or moderate-to-vigorous intensity that gradually increased in duration from 20 min to 60 min over 16 weeks, and (3) a long run at a moderate intensity or moderate-to-vigorous intensity that gradually increased in duration from 20 min to 110 min over 16 weeks. Additionally, participants completed three distance running trials at a moderate or moderate-to-vigorous intensity (Week 6 = 10 km, Week 9 = 10 km, Week 12 = 15 km). Exercise intensity categories were formally defined by the ACSM exercise prescription guidelines: (1) moderate intensity = 46 to less than 64% VO2max, (2) vigorous intensity = 64 to less than 91% VO2max, and (3) near-maximal intensity = greater than or equal to 91% VO2max. Running velocity corresponding to these intensity categories were individually prescribed to each participant by plotting oxygen consumption (VO2 mL/kg/min) against running velocity (km/h) in a regression model derived from a baseline VO2max test. In this way, exercise intensity was completely individualized. In addition to the AET, participants were asked to maintain their regular pattern of physical activity outside of the intervention (e.g., gym, leisure activities, and cycling commutes).

To guide performance and track compliance, participants were issued a computerized and GPS-enabled sportswatch (Garmin Forerunner 235, Garmin, US). This device provided participants real-time estimates of running velocity, and therefore of individual exercise intensity. Participants uploaded their running data to an online database weekly, which provided detailed information on training velocity, distance, and time. Adherence requirements for the AET program were completion of at least 50% of all prescribed runs (target = 48 individual runs [3 runs/week over 16 weeks]; minimum adherence requirement = 24 runs). Average % VO2max across all running sessions, total running distance (km), and total running time (h) were also recorded as measures of dosage.
Intervention code [1] 316141 0
Treatment: Other
Intervention code [2] 316142 0
Behaviour
Intervention code [3] 316143 0
Lifestyle
Comparator / control treatment
No control group
Control group
Uncontrolled

Outcomes
Primary outcome [1] 322043 0
Self-reported chronic psychosocial stress as measured by the Perceived Stress Scale (PSS-10).
Timepoint [1] 322043 0
T0 (Baseline): Prior to the trial period
T1 (Post-intervention: Following completion of the 16-week trial period.
Secondary outcome [1] 377135 0
Self-reported dispositional mindfulness (Mindful Attention Awareness Scale [MAAS] scale).
Timepoint [1] 377135 0
T0 (Baseline): Prior to the trial period
T1 (Post-intervention: Following completion of the 16-week trial period.
Secondary outcome [2] 377136 0
Disposition to use cognitive reappraisal as an emotion regulation strategy (cognitive reappraisal subscale of the Emotion Regulation Questionnaire [ERQ] scale).
Timepoint [2] 377136 0
T0 (Baseline): Prior to the trial period
T1 (Post-intervention: Following completion of the 16-week trial period.
Secondary outcome [3] 377137 0
Rumination: brooding subscale of the Ruminative Responses Scale (RRS)
Timepoint [3] 377137 0
T0 (Baseline): Prior to the trial period
T1 (Post-intervention: Following completion of the 16-week trial period.
Secondary outcome [4] 377138 0
Worry: Penn State Worry Questionnaire (PSWQ)
Timepoint [4] 377138 0
T0 (Baseline): Prior to the trial period
T1 (Post-intervention: Following completion of the 16-week trial period.
Secondary outcome [5] 377549 0
Maximal aerobic capacity (VO2max) was assessed using a graded incremental exercise protocol on a motorized treadmill. During the exercise protocol, a 1% treadmill gradient was maintained to match the energy-cost of outdoor running. The protocol began with treadmill running at 6 km/h, and velocity (i.e., exercise intensity) was increased in increments of 2 km/h every 3 min until volitional exhaustion or until VO2max criteria were obtained. Oxygen consumption (VO2 L/min) was measured continuously using open-circuit spirometry.
Timepoint [5] 377549 0
T0 (Baseline): Prior to the trial period
T1 (Post-intervention: Following completion of the 16-week trial period.
Secondary outcome [6] 377550 0
Aerobic economy: absolute oxygen cost.
This measure was assessed during the maximal aerobic capacity assessment in the final minute of each running velocity (i.e., 2 - 3 min). The final minute at each velocity (e.g., 6, 8, 10, and 12 km/h) represented the steady-state energy requirements for that given exercise intensity. Absolute oxygen cost (VO2 L/min) was measured using open-circuit spirometry.
Timepoint [6] 377550 0
T0 (Baseline): Prior to the trial period
T1 (Post-intervention: Following completion of the 16-week trial period.
Secondary outcome [7] 377676 0
Aerobic economy: relative oxygen cost.
This measure was assessed during the maximal aerobic capacity assessment in the final minute of each running velocity (i.e., 2 - 3 min). The final minute at each velocity (e.g., 6, 8, 10, and 12 km/h) represented the steady-state energy requirements for that given exercise intensity. Absolute oxygen cost (VO2 L/min) was measured using open-circuit spirometry, and relative oxygen cost was computed as the oxygen energy requirement for each velocity as a proportion of total VO2max.
Timepoint [7] 377676 0
T0 (Baseline): Prior to the trial period
T1 (Post-intervention: Following completion of the 16-week trial period.
Secondary outcome [8] 377677 0
Aerobic economy: heart rate.
This measure was assessed during the maximal aerobic capacity assessment in the final minute of each running velocity (i.e., 2 - 3 min). The final minute at each velocity (e.g., 6, 8, 10, and 12 km/h) represented the steady-state energy requirements for that given exercise intensity. At each steady-state period, heart rate (bpm) was recorded using a Polar heart rate monitor.
Timepoint [8] 377677 0
T0 (Baseline): Prior to the trial period
T1 (Post-intervention: Following completion of the 16-week trial period.
Secondary outcome [9] 377678 0
Aerobic economy: perceived exertion.
This measure was assessed during the maximal aerobic capacity assessment in the final minute of each running velocity (i.e., 2 - 3 min). The final minute at each velocity (e.g., 6, 8, 10, and 12 km/h) represented the steady-state energy requirements for that given exercise intensity. At each steady-state period, perceived exertion was recorded using the Borg Rating of Perceived Exertion (RPE) scale (6 = no exertion at all, 20 = maximal exertion).
Timepoint [9] 377678 0
T0 (Baseline): Prior to the trial period
T1 (Post-intervention: Following completion of the 16-week trial period.

Eligibility
Key inclusion criteria
No engagement in regular running training or meditation practice within six months prior to first assessment.
Minimum age
18 Years
Maximum age
35 Years
Gender
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
(1) age not within 18 - 35 years.
(2) prior completion of an endurance event equivalent to a half-marathon (21.1 km).
(3) prior completion of a formal meditation program.
(4) current diagnosis of a neurological or mental disorder.
(5) current diagnosis/history of chronic pain or musculoskeletal conditions.
(6) current diagnosis/history of chronic disease of any kind.
(7) current diagnosis of a heat or cold disorder.
(8) current use of medication that influences the neuroendocrine or immune system.
(9) current injury of any kind (e.g., joint or muscle injury).
(10) current diagnosis of an infectious disease.
(11) BMI >= 30 kg/m2.
(12) pregnancy or suspected pregnancy.

Study design
Purpose of the study
Prevention
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Single group
Other design features
Phase
Not Applicable
Type of endpoint(s)
Efficacy
Statistical methods / analysis
Pilot sample size planning
15 - 20 participants were targeted to provide reasonable estimates of moderate to large effects. To attain at least 15 participants and account for an estimated dropout rate of 30 - 35%, the rule for termination of data collection was set between 24 and 26 participants.

Statistical analysis

Pre-to-post measures with single paired data points included psychosocial stress, mindfulness, emotion regulation factors, and VO2max. Responses to these variables were analyzed using one-sample t tests on T1 - T0 gain scores (t.test: base R). As a sensitivity test to any assumption violations, these variables were also analyzed using robust methods based on T1 - T0 contrasts of the 20% trimmed mean difference using a percentile bootstrap approach.

Pre-to-post measures with multiple data points included aerobic economy variables assessed at 6, 8, 10, and 12 km/h during a VO2max test. These data were arrayed as separate 2 (Time: T1 vs. T0) by 4 (Velocity: 6, 8, 10, and 12 km/h) within-within factorials and analyzed using linear mixed models fit by REML. As a sensitivity test, data were screened for participant and response-level outliers using a criterion of Cook’s distance > 1.

Sample size planning for a future RCT

Sample size planning for a confirmatory trial focused on our primary outcome: PSS-10. The mean difference was divided by the standard deviation of the difference scores to yield the operative effect size: d(z). The lower limit of a 1-sided 80% CI on d(z) was computed as a conservative estimate of the population effect size. This value was entered into an accuracy in parameter estimation sample size analysis with 99% assurance. This process was repeated for between-group operative effect size d statistics for values ranging from d = 0.8 to 0.2 to estimate sample sizes required to detect hypothetical differences in gain scores between difference arms of a RCT.

Feasibility criteria

Feasibility were assessed as retention rate, assessment response rate, recruitment rate, and feasibility sample size requirements for a future RCT.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
VIC

Funding & Sponsors
Funding source category [1] 304337 0
University
Name [1] 304337 0
Monash University
Address [1] 304337 0
Wellington Rd, Clayton VIC 3800
Country [1] 304337 0
Australia
Primary sponsor type
University
Name
Monash University
Address
Wellington Rd, Clayton VIC 3800
Country
Australia
Secondary sponsor category [1] 304588 0
None
Name [1] 304588 0
NA
Address [1] 304588 0
NA
Country [1] 304588 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 304788 0
Monash University Human Research Ethics Committee
Ethics committee address [1] 304788 0
Wellington Rd, Clayton VIC 3800
Ethics committee country [1] 304788 0
Australia
Date submitted for ethics approval [1] 304788 0
20/10/2015
Approval date [1] 304788 0
15/12/2015
Ethics approval number [1] 304788 0
CF15/3863 - 2015001705

Summary
Brief summary
Researchers have begun delivering mindfulness and aerobic exercise training concurrently on the premise that a combination intervention will yield salutary outcomes over and above each intervention alone. An estimate of the effect of combination training on chronic psychosocial stress in a nonclinical population has not been established. The objective of this trial was therefore to assess the preliminary efficacy of combination training for reducing chronic psychosocial stress in a healthy sample, and to establish assurance of protocol feasibility in preparation of a definitive RCT. This trial was designed as a prevention-focused (i.e., primary) intervention to be used by all individuals and not just those presenting with mental health risk factors.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 98206 0
Mr Guy A. Prochilo
Address 98206 0
Level 12, Redmond Barry Building, Melbourne School of Psychological Sciences. University of Melbourne, Parkville, VIC, 3010
Country 98206 0
Australia
Phone 98206 0
+61 3 8344 6377
Fax 98206 0
Email 98206 0
gprochilo@student.unimelb.edu.au
Contact person for public queries
Name 98207 0
Mr Guy A. Prochilo
Address 98207 0
Level 12, Redmond Barry Building, Melbourne School of Psychological Sciences. University of Melbourne, Parkville, VIC, 3010
Country 98207 0
Australia
Phone 98207 0
+61 3 8344 6377
Fax 98207 0
Email 98207 0
gprochilo@student.unimelb.edu.au
Contact person for scientific queries
Name 98208 0
Mr Guy A. Prochilo
Address 98208 0
Level 12, Redmond Barry Building, Melbourne School of Psychological Sciences. University of Melbourne, Parkville, VIC, 3010
Country 98208 0
Australia
Phone 98208 0
+61 3 8344 6377
Fax 98208 0
Email 98208 0
gprochilo@student.unimelb.edu.au

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
These data are not publicly available on the advice of the Monash Ethics Committee because the approved ethics application did not include provisions for public access to data.
What supporting documents are/will be available?
Study protocol
Statistical analysis plan
How or where can supporting documents be obtained?
Type [1] 5801 0
Statistical analysis plan
Citation [1] 5801 0
Prochilo, G. A., Costa, R. J., Hassed, C., Chambers, R., & Molenberghs, P. The Effects of a 16-week Aerobic Exercise and Mindfulness-based Intervention on Chronic Psychosocial Stress: A Nonrandomized Pilot and Feasibility Trial. PsyArXiv Preprints. https://doi.org/10.31234/osf.io/8w45k
Link [1] 5801 0
Email [1] 5801 0
Other [1] 5801 0
Attachment [1] 5801 0
Type [2] 5802 0
Study protocol
Citation [2] 5802 0
Prochilo, G. A., Costa, R. J., Hassed, C., Chambers, R., & Molenberghs, P. The Effects of a 16-week Aerobic Exercise and Mindfulness-based Intervention on Chronic Psychosocial Stress: A Nonrandomized Pilot and Feasibility Trial. PsyArXiv Preprints. https://doi.org/10.31234/osf.io/8w45k
Link [2] 5802 0
Email [2] 5802 0
Other [2] 5802 0
Attachment [2] 5802 0
Type [3] 5803 0
Analytic code
Citation [3] 5803 0
Link [3] 5803 0
Email [3] 5803 0
Other [3] 5803 0
Attachment [3] 5803 0
Summary results
Have study results been published in a peer-reviewed journal?
No
Other publications
Have study results been made publicly available in another format?
Yes
Results – basic reporting
Results – plain English summary