1 INTRODUCTION

Young people experience significant levels of psychological distress (Rickwood et al., 2014; Scott et al., 2012), which impacts their wellbeing and increases the risk of future mental health problems (Arbour-Nicitopoulos et al., 2012).

Exercise, defined as the planned, structured and repetitive undertaking of physical activity for the purposes of maintaining or improving health or skill-related components of physical fitness (Caspersen et al., 1985; Thompson et al., 2013) is an effective way to reduce distress (Goldfield et al., 2011; Perales et al., 2014). However, the experience of psychological distress is associated with reduced physical activity engagement (Olive et al., 2016); and not meeting physical activity guidelines in young people (Arbour-Nicitopoulos et al., 2012). This may be explained by low mood and stress, which contribute to psychological distress, and are common barriers towards exercise engagement (Firth et al., 2016). Additionally, low motivation, poor self-efficacy and fatigue, which are characteristic of mental health concerns may also pose barriers to physical activity engagement (Chapman et al., 2016).

Mindfulness is defined as the awareness that arises from paying attention to the present moment, non-judgmentally (Kabat-Zinn, 2003), and has been shown to reduce psychological distress in young people (Parto & Besharat, 2011; Sibinga et al., 2011; Tan & Martin, 2013). Mindfulness training enhances self-regulation of emotion and behaviours (Jimenez et al., 2010; Malinowski, 2013; Shapiro et al., 2006; Tang et al., 2015) due to greater acceptance and self-awareness of unpleasant emotions and distress, rather than impulsive reaction, rumination or avoidance of these (Baer, 2003; Kabat-Zinn & Hanh, 2009; Kavanagh et al., 2004). This enhanced acceptance of experiences is thought to lead to increased distress tolerance (Carpenter et al., 2019). Therefore, mindfulness could be associated with reduced perceived barriers to exercise engagement, through greater acceptance of negative or uncomfortable thoughts or sensations related to exercise engagement, such as low mood, fatigue or feeling self-conscious (Firth et al., 2016); (Parker et al., 2021). Thus, the current study aimed to examine the relationship between mindfulness, psychological distress and physical activity outcomes in help-seeking young Australians.

2 METHODS 2.1 Participants

Participants were help-seeking young people (15–25 years) at headspace youth mental health services in the northern and western suburbs of Melbourne (N = 88). There were no mental health inclusion criteria; however, young people most commonly present to headspace with mood disorders or anxiety (Rickwood et al., 2014).

2.2 Measures

Participants provided key demographic information (i.e., age, gender, employment, country of birth, etc.).

2.3 Mindfulness

Dispositional mindfulness was assessed using The Mindful Attention Awareness Scale (MAAS), a validated 15-item scale that is designed to assess the characteristics of mindfulness. Participants responded on a 6-point Likert scale ranging from 1, indicating ‘almost always’ to 6 indicating ‘almost never.’ The MAAS has a good internal reliability (α = 0.89) (Brown & Ryan, 2003; MacKillop & Anderson, 2007).

2.4 Psychological distress

Psychological distress over the past 30 days was assessed using the Kessler

Psychological Distress Scale (K-10), with 1 indicating ‘none of the time’ and 5 indicating ‘all of the time’ (Kessler et al., 2002). The Cronbach's alpha for the K-10 in the present study was .91, indicating excellent internal reliability.

2.5 Motivation for physical activity

Motivation towards PA was assessed using the Behavioural Regulation in Exercise Questionnaire (BREQ-3; Markland & Tobin, 2004; Wilson, Rogers, Rodgers, & Wild, 2006), which measures amotivation, external regulation, introjected motivation, identified motivation and intrinsic motivation. Cronbach's alpha for the subscales ranged from 0.74 to 0.92, indicating acceptable to excellent internal reliability for each of the subscales. External and introjected motivation were combined to compute a controlled motivation variable (2* external motivation + introjected motivation) and intrinsic and identified motivation were combined to form an autonomous motivation variable (3* intrinsic motivation +2* integrated motivation + identified motivation).

2.6 Benefits and barriers of physical activity

Perceived exercise benefits and barriers were assessed using the Adolescent Physical.

Activity Perceived Benefits and Barriers Scales (Robbins et al., 2008). Participants respond to items on a 4-point Likert scale, with 1 indicating ‘not true at all’ and 4 indicating ‘very true.’ Additional items were added for this study to address financial barriers, socio-cultural barriers and psychological benefits and barriers. The internal Cronbach's alpha for the benefits and barriers scales were 0.88 and 0.79 respectively.

2.7 Moderate-to-vigorous physical activity

Engagement in moderate-to-vigorous physical activity (MVPA) was measured using the International Physical Activity Questionnaire—Short Form (IPAQ-SF; Craig et al., 2003). Levels of MVPA were calculated as metabolic equivalent minutes using the IPAQ-SF guidelines for data processing (International Physical Activity Questionnaire, 2005).

2.8 Statistical analyses

Data was analysed using SPSS 25.0 and was checked for missingness. Missing data was minimal (6.1% of values missing) and determined to be missing completely at random (Little's MCAR χ2 [258] = 295.74, p > .05). To increase power of analyses, missing data was imputed using expectation maximization.

Descriptive statistics were calculated for participant characteristics. Differences in mindfulness between socio-demographic variables were estimated using independent sample t-tests and one-way ANOVA. Bivariate associations between predictor variables and outcome variables were estimated using Pearson's product moment correlation. Levels of MVPA were positively skewed, so it was transformed using natural logarithm before correlations were calculated.

Variables were selected for mediation analysis based on the criteria suggested by Baron and Kenny (1986); (i) correlation between independent variable and outcome, (ii) correlation between independent variable and mediator and (iii) correlation between mediator and outcome. Mediation was conducted using the PROCESS macro in SPSS (v3.5; Hayes, 2017). Due to the relatively small sample size, bias-correcting bootstrapping was used to examine the indirect effect and was completed with 5000 resamples. As no potential covariates were statistically significant and indicated as potential confounders based on previous literature, no covariates were entered into the model.

3 RESULTS 3.1 Descriptive statistics and difference in dependent variable between groups

Descriptive statistics and significance values are shown in Table 1. On average, participants were aged 19.98 years (SD = 2.86) and had a mean K10 score of 29.02 (SD = 8.86). Based on K10 scores, 17% of participants were likely to be well, 19.3% of participants likely had a mild disorder, 15.9% likely had a moderate disorder and 47.7% likely had a severe disorder. The median level of physical activity was 1332 MET minutes/week (IQR = 2189). The mean dispositional mindfulness score was 3.23 (SD = 0.90) of a possible 15. Dispositional mindfulness was higher among those who were not currently studying compared with those who were (p = .029). Dispositional mindfulness scores did not significantly differ based on any other characteristics.

TABLE 1. Descriptive statistics and significance values for testing of differences in mindfulness between demographic groups MASSa n (%) M (SD) p Gender Male 21 (23.90%) 3.25 (0.97) .285 Female 58 (65.90%) 3.31 (0.81) Other gender identity 9 (10.20%) 2.81 (1.09) Age 15–18 23 (26.10%) 3.15 (0.91) .738 19–25 39 (44.30%) 3.23 (0.90) Missing 26 (29.50%) 3.35 (0.84) SEIFAc Q1 23 (26.10%) 3.25 (0.94) .66 Q2 21 (23.90%) 3.23 (0.99) Q3 22 (25.00%) 3.40 (0.75) Q4 21 (23.90%) 3.06 (0.86) Smoking status Non-smoker 66 (75.00%) 3.34 (0.88) .091 Smoker 22 (25.00%) 2.97 (0.83) Employment status Employed 38 (43.20%) 3.22 (0.91) .817 Unemployed 50 (56.80%) 3.27 (0.87) Highest level of education High school certificate or less 60 (68.20%) 3.27 (0.88) .941 Further education 27 (30.70%) 3.26 (0.84) Missing 1 (1.10%) Study status Studying 55 (62.50%) 3.09 (0.91) .029 Not studying 33 (37.50%) 3.51 (0.81) Country of birth Born in Australia 79 (89.80%) 3.24 (0.85) .84 Born Overseas 9 (10.20%) 3.30 (1.18) Language spoken at home English 60 (68.20%) 3.25 (0.86) .934 Language other than English 28 (31.80%) 3.24 (0.94) Sexual orientation Heterosexual or straight 43 (48.90%) 3.36 (0.84) .256 LGBTQI identifying 45 (51.10%) 3.14 (0.91) Living situation Living in family home 65 (73.90%) 3.29 (0.84) .409 Living out of family home 23 (26.10%) 3.12 (0.98) Main reason for attending headspace centreb Problems with how I feel 52 (59.10%) 3.25 (0.96) .984 Other reason 36 (40.90%) 3.25 (0.77) a Difference between groups estimated using independent sample t-tests and one-way ANOVA. b Other reasons included problems with relationships, physical health, school or work, or alcohol and other drugs. c Socio-economic Indexes for Areas (SEIFA). 3.2 Bivariate correlations

Table 2 shows the bivariate Pearson correlation of exercise barriers with each predictor variable. Distress (K-10) and exercise barriers had significant inverse correlations with dispositional mindfulness (MAAS). Variables associated with motivation for physical activity were not associated with distress or mindfulness. Mindfulness and levels of MVPA were not significantly associated. As such, motivation for physical activity variables and level of MVPA were not included in mediation analyses.

TABLE 2. Correlations of exercise barriers with predictor variables 1 2 3 4 5 6 7 8 9 10 1. Dispositional mindfulness – 2. Psychological distress −.50* – 3. Exercise benefits −.02 −.13 – 4. Exercise barriers −.37* .47* −.05 – 5. Autnomous motivation .05 .02 .38* −.18 – 6. Controlled motivation .07 −.12 .53* −.00 .10 – 7. Amotivation .11 −.09 −.03 .07 −.40* .34* – 8. Exercise intention .09 −.11 .59* −.31* .51* .32* −.15 – 9. Attitudes towards physical activity .15 −.14 .46* −.32* .59* .06 −.57* .64* – 10. Moderate-vigorous physical activity (MVPA)a .07 −.07 .32* −.29* .48* .03 −.31* .43* .44* – * p < .01. a Log transformed. 3.3 Mediation analysis

The total and specific indirect effects of the mediation analysis of dispositional mindfulness on psychological distress and exercise barriers are summarized in Figure 1. Greater dispositional mindfulness was associated with fewer exercise barriers via lower psychological distress (ab = −0.19, 95%CI −0.34, −0.08). Additionally, when controlling for psychological distress the association between dispositional mindfulness and exercise barriers was no longer significant (c = −0.17, 95%CI = −0.34, 0.04).

Mediation analysis of psychological distress on mindfulness and exercise barriers

4 DISCUSSION

This study found that mindfulness is associated with reduced perceived barriers to exercise via reductions in psychological distress in help-seeking young people. Our findings are consistent with previous research among Australian university students, showing that higher levels of mindfulness are associated with lower levels of distress and that dispositional mindfulness is a significant mediator of several dimensions of self-care, including physical activity, and psychological distress (Slonim et al., 2015). Collectively, the current and previous findings indicate that initiatives aimed to increase mindfulness in help-seeking young people may be an effective method via which to decrease perceived exercise barriers. To our knowledge, no studies have trialled mindfulness-based strategies to reduce distress as a means to improve exercise engagement in young people seeking help for mental ill-health. This is an important area for future research. In addition to increasing mindfulness, it may also be important to consider the type of exercise activities that are offered to young people experiencing distress. Previous work in adults has shown that those with high levels of distress are averse to competitive activities, suggesting that the experience of distress may be a barrier to specific types of exercise (Khan et al., 2013) and for those with mental health concerns, a focus on performance and winning can be particularly damaging to a person's self-worth and wellbeing (Carless & Douglas, 2010).

While the current findings can guide future research and interventions to support exercise engagement in young people experiencing psychological distress, it has some limitations. First, the majority of respondents were women (65.9%) and thus, findings may not generalize to the wider community. This study was cross-sectional and thus neither causality nor directionality can be assumed. More specifically, associations between PA and mental health may be bidirectional (Pascoe & Parker, 2019), which was not examined in this study. Further, it is also possible that mindfulness may impact exercise barriers The following should be considered in interpretation of these results and would be worthwhile exploring in future research; we did not explore if the perceived barriers to exercise engagement differed by type of activity, and use of additional items included in the Adolescent Physical Activity Perceived Benefits and Barriers Scales may impact measure validity. Data from the current sample found that mindfulness levels were not associated with actual levels of exercise engagement (Table 2). Therefore, while addressing perceived barriers to exercise is necessary to increase exercise engagement (Biddle et al., 2015), doing so is likely insufficient to increase levels of exercise engagement among help-seeking young people. Future work should explore the relationship between mindfulness, perceived barriers and other relevant factors that impact levels of exercise engagement. As young people hold positive views of the potential of physical activity as part of mental health treatment (Parker et al.,  2021) future studies may examine integrating mindfulness approaches to exercise engagement within psychological treatment.

4.1 Conclusion

Dispositional mindfulness may reduce perceived barriers to exercise engagement in help-seeking young people, however future studies should also account for other factors that influence exercise engagement levels.

ACKNOWLEDGEMENT

We gratefully acknowledge the clinical and management staff of headspace Sunshine, Glenroy, Werribee and Craigieburn for supporting the project. Portions of the data collected in this project was included in an Honours of Psychology thesis by ET, supervised by AGP and MP.

CONFLICT OF INTEREST

The authors declare no conflict of interest.