Randomized controlled trial of mindfulness meditation and exercise for the prevention of acute respiratory infection: possible mechanisms of action

Individual participant data systematic review and meta-analysis of randomised controlled trials assessing adult mindfulness-based programmes for mental health promotion in non-clinical settings

Introduction

Mindfulness-based programmes (MBPs) are widely used to prevent mental ill-health that is becoming the leading global cause of morbidity. Evidence suggests beneficial average effects but wide variability. We aimed to confirm the effect of MBPs on psychological distress, and to understand whether and how baseline distress, gender, age, education, and dispositional mindfulness modify the effect of MBPs on distress among adults in non-clinical settings.

Methods

We conducted a pre-registered systematic review and individual participant data (IPD) meta-analysis (PROSPERO CRD42020200117). Thirteen databases were searched in December 2020 for randomised controlled trials satisfying a quality threshold and comparing in-person, expert-defined MBPs in non-clinical settings with passive control groups. Two researchers independently selected, extracted, and appraised trials using the revised Cochrane Risk-of-Bias Tool (RoB2). Anonymised IPD of eligible trials were sought from collaborating authors. The primary outcome was psychological distress (unpleasant mental or emotional experiences including anxiety and depression) at 1 to 6 months after programme completion. Data were checked and imputed if missing. Pairwise, random-effects, two-stage IPD meta-analyses were conducted. Effect modification analyses followed a within-studies approach. Public and professional stakeholders were involved in the planning, conduct and dissemination of this study.

Results

Fifteen trials were eligible, 13 trialists shared IPD (2,371 participants representing 8 countries, median age 34 years-old, 71% women, moderately distressed on average, 20% missing outcome data). In comparison with passive control groups, MBPs reduced average distress between one- and six-months post-intervention with a small to moderate effect size (standardised mean difference (SMD) -0.32; 95% confidence interval (CI) -0.41 to -0.24; p-value < 0.001; 95% prediction interval (PI) -0.41 to -0.24 (no heterogeneity)). Results were robust to sensitivity analyses, and similar for the other psychological distress time point ranges. Confidence in the primary outcome result is high. We found no clear indication that this effect is modified by baseline psychological distress, gender, age, education level, or dispositional mindfulness.

Conclusions

Group-based teacher-led MBPs generally reduce psychological distress among community adults who volunteer to receive this type of intervention. More research is needed to identify sources of variability in outcomes at an individual level.

Validation of the Wisconsin upper respiratory symptom survey-24, Chinese version

BACKGROUND

The Wisconsin upper respiratory symptom survey (WURSS) is a validated English questionnaire to evaluate the quality of life and severity of upper respiratory tract infections (URTIs). We aimed to develop a Mandarin Chinese version of WURSS-24 (WURSS-24-C) and evaluate its reliability, validity and minimal important difference (MID).

METHODS

The WURSS-24-C was developed using the forward-backward translation procedure. People with URTIs' symptoms within 48 h of onset were recruited and asked to fill in the WURSS-24-C daily for up to 14 d. Exploratory and confirmatory factor analyses were used to suggest domains. The 8-Item Short Form Health Survey (SF-8) assessing general mental and physical health was used to assess validity. Reliability estimated by Cronbach's alpha and mean day-to-day change for those indicating minimal improvement as MID were evaluated.

RESULTS

The WURSS-24-C was found to be acceptable, relevant, and easy to complete in cognitive debriefing interviews. A total number of 300 participants (age 28.4 ± 9.3, female 70%) were monitored for 2500 person-days. Four domains (activity and function, systemic symptoms, nasal symptoms and throat symptoms) of the WURSS-24-C were confirmed (comparative fit index [CFI] = 0.93). The reliability of this 4-domain-structure is good (Cronbach's alphas varied from 0.849 to 0.943). Convergent validity is moderate (Pearson correlation coefficients between daily WURSS-24-C and the SF-8 were -0.780 and -0.721, for the SF-8 physical and mental health, respectively). Estimates of MID for individual items varied from -0.41 to -1.14.

CONCLUSIONS

The WURSS-24-C is a reliable and valid questionnaire for assessing illness-specific quality-of-life health status in Chinese-speaking patients with URTIs.Key messagesThe Wisconsin upper respiratory symptom survey (WURSS) series are patient-oriented questionnaire instruments assessing the quality of life and severity of upper respiratory tract infections (URTIs).The WURSS-24 was translated into Mandarin Chinese using the forward-backward translation procedure, and evaluated its validity, reliability and minimal important difference (MID) in 300 Chinese participants with URTIs.The WURSS-24 Chinese version (WURSS-24-C) seems to be a reliable and valid questionnaire for assessing illness-specific quality-of-life health status in Chinese patients with URTIs.

Yoga, Meditation, Breathing Exercises, and Inflammatory Biomarkers with Possible Implications in COVID-19: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Introduction

COVID-19, a multisystem disease, has implications for various immunity and infection biomarkers. Yoga (Y), meditation (M), and pranayama (P), and their combinations have shown positive changes on those biomarkers among other than COVID-19 patients and healthy people. So, we aimed to document the evidence of possible implication in a systematic way.

Materials and Methods

We screened 84 full texts, published in the last ten years, from three databases, from which only 44 met the eligibility criteria, and then extracted the data related to demographic characteristics, intervention, results, and strengths and limitations in two MS-Excel grids, and then presented them in tables and figures. Furthermore, we carried out meta-analysis including subgroup and sensitivity analysis using a random effects model of 11 RCTs and reported the mean difference, heterogeneity, and p value with 95% CI and presented them with forest and funnel plots and the tables.

Results

Twenty-five biomarkers of 4023 participants (range, 15-413) from 13 countries, healthy and clinical, from both sexes above 18 years, and from mainly clinical settings, were reported. YMP intervention, in solitary or in different possible combinations with varied durations among clinical and pregnant (range, 960-4800 minutes) and healthy (960-8400 minutes, excluding two studies of 20 minutes only) participants, was reported. It was revealed that 25 biomarkers, nine among the apparently healthy, 14 among the patients, and two among the pregnant, changed favourably (p < 0.05). Furthermore, either in meta- or subgroup-analysis, mean differences of IL-6 (-1.44 pg/ml) (95% CI) (-2.33, -0.55), (p = 0.002, I ²  = 82%), Cortisol (-40.75 pg/ml) (95% CI) (-64.13, -17.38), (p = 0.0006, I ²  = 87%), and TNF-α (-3.40 pg/ml) (95% CI) (-4.83, -1.98), (p < 0.0001, I ²  = 79%) showed statistically significant changes. Nonetheless, considerable heterogeneity and publication bias were observed among the studies.

Conclusion

Although more than two dozens of biomarkers in individual studies showed favourable changes, only IL-6, Cortisol, and TNF-α produced significant combined results, even then with much less certainty. Further meta-analysis of biomarkers of COVID-19 patients is highly recommended. Registration: CRD42021283894.

Mindfulness-based programmes for mental health promotion in adults in nonclinical settings: A systematic review and meta-analysis of randomised controlled trials

BACKGROUND

There is an urgent need for mental health promotion in nonclinical settings. Mindfulness-based programmes (MBPs) are being widely implemented to reduce stress, but a comprehensive evidence synthesis is lacking. We reviewed trials to assess whether MBPs promote mental health relative to no intervention or comparator interventions.

METHODS AND FINDINGS

Following a detailed preregistered protocol (PROSPERO CRD42018105213) developed with public and professional stakeholders, 13 databases were searched to August 2020 for randomised controlled trials (RCTs) examining in-person, expert-defined MBPs in nonclinical settings. Two researchers independently selected, extracted, and appraised trials using the Cochrane Risk-of-Bias Tool 2.0. Primary outcomes were psychometrically validated anxiety, depression, psychological distress, and mental well-being questionnaires at 1 to 6 months after programme completion. Multiple testing was performed using p < 0.0125 (Bonferroni) for statistical significance. Secondary outcomes, meta-regression and sensitivity analyses were prespecified. Pairwise random-effects multivariate meta-analyses and prediction intervals (PIs) were calculated. A total of 11,605 participants in 136 trials were included (29 countries, 77% women, age range 18 to 73 years). Compared with no intervention, in most but not all scenarios MBPs improved average anxiety (8 trials; standardised mean difference (SMD) = -0.56; 95% confidence interval (CI) -0.80 to -0.33; p-value < 0.001; 95% PI -1.19 to 0.06), depression (14 trials; SMD = -0.53; 95% CI -0.72 to -0.34; p-value < 0.001; 95% PI -1.14 to 0.07), distress (27 trials; SMD = -0.45; 95% CI -0.58 to -0.31; p-value < 0.001; 95% PI -1.04 to 0.14), and well-being (9 trials; SMD = 0.33; 95% CI 0.11 to 0.54; p-value = 0.003; 95% PI -0.29 to 0.94). Compared with nonspecific active control conditions, in most but not all scenarios MBPs improved average depression (6 trials; SMD = -0.46; 95% CI -0.81 to -0.10; p-value = 0.012, 95% PI -1.57 to 0.66), with no statistically significant evidence for improving anxiety or distress and no reliable data on well-being. Compared with specific active control conditions, there is no statistically significant evidence of MBPs' superiority. Only effects on distress remained when higher-risk trials were excluded. USA-based trials reported smaller effects. MBPs targeted at higher-risk populations had larger effects than universal MBPs. The main limitation of this review is that confidence according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach is moderate to very low, mainly due to inconsistency and high risk of bias in many trials.

CONCLUSIONS

Compared with taking no action, MBPs of the included studies promote mental health in nonclinical settings, but given the heterogeneity between studies, the findings do not support generalisation of MBP effects across every setting. MBPs may have specific effects on some common mental health symptoms. Other preventative interventions may be equally effective. Implementation of MBPs in nonclinical settings should be partnered with thorough research to confirm findings and learn which settings are most likely to benefit.

Mindfulness versus Physical Exercise: Effects of Two Recovery Strategies on Mental Health, Stress and Immunoglobulin A during Lunch Breaks. A Randomized Controlled Trial

This research analyses the effects of mindfulness meditation (MM) and physical exercise (PE), practised as daily recovery activities during lunch breaks, on perceived stress, general mental health, and immunoglobin A (IgA). A three-armed randomized controlled trial with 94 employees was conducted for five weeks including two follow-up sessions after one and six months. Daily practice lasted 30 min maximum. Perceived stress and general mental health questionnaires and saliva samples were used. There were significant differences in time factor comparing pre- and post-test of Perceived Stress Questionnaire (PSQ) both for PE [Mdiff = 0.10, SE = 0.03, p = 0.03], and for MM [Mdiff = 0.09, SE = 0.03, p = 0.03]. Moreover, there were significant differences of interaction factor when comparing MM vs. PE in total score at pre-post [F = −2.62 (6, 168.84), p = 0.02, ω² = 0.09], favoring PE with medium and high effect sizes. Regarding General Health Questionnaire (GHQ) variable, practicing MM showed significant effects in time factor compared to pre-Fup2. No significant differences were found for IgA. Thus, practicing both MM and PE as recovery strategies during lunch breaks could reduce perceived stress after five weeks of practice, with better results for PE. Moreover, practicing MM could improve mental health with effects for 6 months.

Exercise versus no exercise for the occurrence, severity, and duration of acute respiratory infections

BACKGROUND

Acute respiratory infections (ARIs) last for less than 30 days and are the most common acute diseases affecting people. Exercise has been shown to improve health generally, but it is uncertain whether exercise may be effective in reducing the occurrence, severity, and duration of ARIs. This is an update of our review published in 2015.

OBJECTIVES

To evaluate the effectiveness of exercise for altering the occurrence, severity, or duration of acute respiratory infections.

SEARCH METHODS

We searched CENTRAL (2020, Issue 2), MEDLINE (1948 to March week 1, 2020), Embase (1974 to 05 March 2020), CINAHL (1981 to 05 March 2020), LILACS (1982 to 05 March 2020), SPORTDiscus (1985 to 05 March 2020), PEDro (searched 05 March 2020), OTseeker (searched 05 March 2020), and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) and ClinicalTrials.gov (searched 05 March 2020).

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs (method of allocation that is not truly random, e.g. based on date of birth, medical record number) of exercise for ARIs in the general population.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data from the included trials using a standard form. One review author entered data, which a second review author checked. We contacted trial authors to request missing data. There were sufficient differences in the populations trialed and in the nature of the interventions to use the random-effects model (which makes fewer assumptions than the fixed-effect model) in the analysis.

MAIN RESULTS

We included three new trials for this update (473 participants) for a total of 14 trials involving 1377 adults, published between 1990 and 2018. Nine trials were conducted in the USA, and one each in Brazil, Canada, Portugal, Spain, and Turkey. Sample sizes ranged from 16 to 419 participants, aged from 18 to 85 years. The proportion of female participants ranged from 52% to 100%. Follow-up duration ranged from 1 to 36 weeks (median = 12 weeks). Moderate-intensity aerobic exercise (walking, bicycling, treadmill, or a combination) was evaluated in 11 trials, and was most commonly prescribed at least three times a week for 30 to 45 minutes. There was no difference between exercise and no exercise in the number of ARI episodes per person per year (risk ratio (RR) 1.00, 95% confidence interval (CI) 0.77 to 1.30; 4 trials; 514 participants; low-certainty evidence); proportion of participants who experienced at least one ARI over the study period (RR 0.88, 95% CI 0.72 to 1.08; 5 trials; 520 participants; low-certainty evidence); and the number of symptom days per episode of illness (mean difference (MD) -0.44 day, 95% CI -2.33 to 1.46; 6 trials; 557 participants; low-certainty evidence). Exercise reduced the severity of ARI symptoms measured on the Wisconsin Upper Respiratory Symptom Survey (WURSS-24) (MD -103.57, 95% CI -198.28 to -8.87; 2 trials; 373 participants; moderate-certainty evidence) and the number of symptom days during follow-up period (MD -2.24 days, 95% CI -3.50 to -0.98; 4 trials; 483 participants; low-certainty evidence). Excercise did not have a significant effect on laboratory parameters (blood lymphocytes, salivary secretory immunoglobulin, and neutrophils), quality of life outcomes, cost-effectiveness, and exercise-related injuries. There was no difference in participant dropout between the intervention and control groups. Overall, the certainty of the evidence was low, downgraded mainly due to limitations in study design and implementation, imprecision, and inconsistency. Seven trials were funded by public agencies; five trials did not report funding; and two trials were funded by private companies.

AUTHORS' CONCLUSIONS

Exercise did not reduce the number of ARI episodes, proportion of participants experiencing at least one ARI during the study, or the number of symptom days per episode of illness. However, exercise reduced the severity of ARI symptoms (two studies) and the number of symptom days during the study follow-up period (four studies). Small study size, risk of bias, and heterogeneity in the populations studied contributed to the uncertainty of the findings. Larger trials that are designed to avoid risk of bias associated with participant selection, blinding of outcomes assessors, and with adequate reporting of all outcomes proposed for measurement in trials, would help to provide more robust evidence.

Predictors of Mindfulness Meditation and Exercise Practice, from MEPARI-2, a randomized controlled trial

Objectives

Health-supporting behaviors can be challenging to initiate and maintain. Data from the MEPARI-2 randomized trial were used to assess predictors of sustained exercise and meditation practice.

Methods

Adults aged 30 to 69 years not exercising regularly and without prior meditation training were randomized to 8-week trainings in mindfulness meditation, moderate intensity exercise, or observational control, and monitored for 8 months. Exercise participants reported day-to-day minutes of moderate and vigorous activity; mindfulness meditation participants reported minutes of informal and formal practice. Demographic characteristics and psychosocial factors were assessed as predictors of practice. Growth mixture modeling was used to identify higher and lower practice subgroups.

Results

413 participants (75.8% female; mean (SD) age 49.7 (11.6) years) were randomized to exercise (137), mindfulness meditation (138), or control (138), with 390 (95%) completing the study. Seventy-nine percent of exercisers and 62% of meditators reported ≥150 minutes/week practice for at least half of the 37 weeks monitored. Self-reported minutes of mindfulness meditation and/or exercise practice were significantly (p<0.01) predicted by baseline levels of: general mental health, self-efficacy, perceived stress, depressive symptoms, openness, neuroticism, physical activity, smoking status, and number of social contacts. Growth mixture modeling identified subsets of people with moderate (100-200 min/week) and high (300-450 min/week) levels of self-reported practice for both mindfulness meditation (62% moderate; 38% high) and exercise (71% moderate; 29% high).

Conclusions

In this sample, participants randomized to behavioral trainings reported high levels of practice sustained over 37 weeks. Baseline psychosocial measures predicted practice levels in expected directions.

Meditation or exercise for preventing acute respiratory infection (MEPARI-2): A randomized controlled trial

Background

Practice of meditation or exercise may enhance health to protect against acute infectious illness.

Objective

To assess preventive effects of meditation and exercise on acute respiratory infection (ARI) illness.

Design

Randomized controlled prevention trial with three parallel groups.

Setting

Madison, Wisconsin, USA.

Participants

Community-recruited adults who did not regularly exercise or meditate.

Methods

1) 8-week behavioral training in mindfulness-based stress reduction (MBSR); 2) matched 8-week training in moderate intensity sustained exercise (EX); or 3) observational waitlist control. Training classes occurred in September and October, with weekly ARI surveillance through May. Incidence, duration, and area-under-curve ARI global severity were measured using daily reports on the WURSS-24 during ARI illness. Viruses were identified multiplex PCR. Absenteeism, health care utilization, and psychosocial health self-report assessments were also employed.

Results

Of 413 participants randomized, 390 completed the trial. In the MBSR group, 74 experienced 112 ARI episodes with 1045 days of ARI illness. Among exercisers, 84 had 120 episodes totaling 1010 illness days. Eighty-two of the controls had 134 episodes with 1210 days of ARI illness. Mean global severity was 315 for MBSR (95% confidence interval 244, 386), 256 (193, 318) for EX, and 336 (268, 403) for controls. A prespecified multivariate zero-inflated regression model suggested reduced incidence for MBSR (p = 0.036) and lower global severity for EX (p = 0.042), compared to control, not quite attaining the p<0.025 prespecified cut-off for null hypothesis rejection. There were 73 ARI-related missed-work days and 22 ARI-related health care visits in the MBSR group, 82 days and 21 visits for exercisers, and 105 days and 24 visits among controls. Viruses were identified in 63 ARI episodes in the MBSR group, compared to 64 for EX and 72 for control. Statistically significant (p<0.05) improvements in general mental health, self-efficacy, mindful attention, sleep quality, perceived stress, and depressive symptoms were observed in the MBSR and/or EX groups, compared to control.

Conclusions

Training in mindfulness meditation or exercise may help protect against ARI illness.

Limitations

This trial was likely underpowered.

Trial registration

Clinicaltrials.gov NCT01654289

Mediational pathways of meditation and exercise on mental health and perceived stress: A randomized controlled trial

This study investigated the effects of mindfulness and exercise training on indicators of mental health and stress by examining shared mediators of program effects. Community-recruited adults (N = 413) were randomized into one of three conditions: (a) mindfulness-based stress reduction, (b) moderate intensity exercise, or (c) wait-list control. Composite indicator structural equation models estimated direct, indirect, and total effects. Results showed that mindfulness-based self-efficacy fulfilled a prominent role in mediating meditation and exercise program effects. Findings suggest that mindfulness and exercise training share similar mechanisms that can improve global mental health, including adaptive responses to stress.

Mindful Climate Action: Health and Environmental Co-Benefits from Mindfulness-Based Behavioral Training

Greenhouse gases from human activities are causing climate change, creating risks for people around the globe. Behaviors involving transportation, diet, energy use, and purchasing drive greenhouse gas emissions, but are also related to health and well-being, providing opportunity for co-benefits. Replacing shorter automobile trips with walking or cycling, or eating plants rather than animals, for example, may increase personal health, while also reducing environmental impact. Mindfulness-based practices have been shown to enhance a variety of health outcomes, but have not been adapted towards environmental purposes. We designed the Mindful Climate Action (MCA) curriculum to help people improve their health while simultaneously lowering their carbon footprints. Combining mindfulness-based practices with the Stages of Change theory, the MCA program aims to: (1) improve personal health and well-being; (2) decrease energy use; (3) reduce automobile use; (4) increase active transport; (5) shift diet towards plant-based foods; and (6) reduce unnecessary purchasing. Mindfulness practices will foster attentional awareness, openness, and response flexibility, supporting positive behavior change. We plan to test MCA in a randomized controlled trial, with rigorous assessment of targeted outcomes. Our long-term goal is to refine and adapt the MCA program to a variety of audiences, in order to enhance public health and environmental sustainability.

Mindfulness in people with a respiratory diagnosis: A systematic review

OBJECTIVES

To describe how mindfulness is delivered and to examine the effect of mindfulness on health-related quality of life (HRQOL), mindful awareness and stress in adults with a respiratory diagnosis.

METHOD

Five electronic databases were searched. Data were extracted and assessed for quality by two reviewers.

RESULTS

Data were extracted from four studies. Interventions were based on Mindfulness-Based Stress Reduction and delivered by trained instructors. Recordings of mindfulness were provided for home-based practice. One study targeted the intervention exclusively to anxious individuals with a respiratory diagnosis. Adherence to mindfulness was poor. No effects were seen on disease-specific HRQOL (standardized mean difference (SMD)=-0.21 95% CI: -0.36 to 0.48, p=0.78), mindful awareness (SMD=0.09 95% CI: -0.34 to 0.52, p=0.68) or stress levels (SMD =-0.11 95% CI: -0.46 to 0.23, p=0.51).

CONCLUSION

Mindfulness interventions, delivered to individuals with a respiratory diagnosis, varied widely in terms of delivery and the outcomes assessed making it difficult to draw any conclusions regarding its effectiveness.

Exercise versus no exercise for the occurrence, severity and duration of acute respiratory infections

BACKGROUND

Acute respiratory infections (ARIs) last for less than 30 days and are the most common acute diseases affecting people worldwide. Exercise has been shown to improve health generally and may be effective in reducing the occurrence, severity and duration of acute respiratory infections.

OBJECTIVES

To evaluate the effectiveness of exercise for altering the occurrence, severity or duration of acute respiratory infections.

SEARCH METHODS

We searched CENTRAL (2014, Issue 6), MEDLINE (1948 to July week 1, 2014), EMBASE (2010 to July 2014), CINAHL (1981 to July 2014), LILACS (1982 to July 2014), SPORTDiscus (1985 to July 2014), PEDro (searched on 11 July 2014), OTseeker (searched on 11 July 2014), the WHO International Clinical Trials Registry Platform (ICTRP) and ClinicalTrials.gov (searched on 11 July 2014).

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs of exercise for ARIs in the general population.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data from the included trials using a standard form. We contacted trial authors to request missing data. One review author entered data and a second review author checked this. There were sufficient differences in the populations trialled and in the nature of the interventions to use the random-effects model (which makes fewer assumptions than the fixed-effect model) in the analysis.

MAIN RESULTS

We included 11 trials involving 904 adults, published between 1990 and 2014. Eight studies were conducted in the USA, and one each in Canada, Spain and Turkey. Sample sizes ranged from 20 to 154 participants aged between 18 and 85 years old. The proportion of female participants varied between 52% and 100%. The duration of follow-up in the studies varied from seven days to 12 months. The exercise type most prescribed for the intervention was aerobic (walking in 70% of the studies, or bicycle riding or treadmill) at least five times a week. Duration was 30 to 45 minutes at moderate intensity. Participants were supervised in 90% of the studies.For four of the primary outcomes the results did not differ significantly and all were low-quality evidence (number of ARI episodes per person per year, rate ratio 0.91 (95% confidence interval (CI) 0.59 to 1.42); proportion of participants who experienced at least one ARI over the study period, risk ratio 0.76 (95% CI 0.57 to 1.01); severity of ARI symptoms, mean difference (MD) -110 (95% CI -324 to 104); and number of symptom days in the follow-up period, MD -2.1 days (95% CI -4.4 to 0.3)). However, one primary outcome, the number of symptom days per episode of illness, was reduced in those participants who exercised (MD -1.1 day, 95% CI -1.7 to -0.5, moderate-quality evidence).We found no significant differences for the secondary outcomes (laboratory parameters (blood lymphocytes, salivary secretory immunoglobulin and neutrophils); quality of life outcomes; cost-effectiveness and exercise-related injuries).There was good adherence to the intervention with no difference between the exercise and non-exercise groups.We rated the quality of evidence for the primary outcomes as low for most outcomes using the GRADE criteria: allocation concealment was not reported and there was a lack of blinding; in addition, there was imprecision (the CI is very wide because of a small number of participants) and inconsistency, which may be due to differences in study design.

AUTHORS' CONCLUSIONS

We cannot determine whether exercise is effective at altering the occurrence, severity or duration of acute respiratory infections. One analysis of four trials suggests that the number of days of illness per episode of infection might be reduced by exercise. The small size of the studies, risk of bias and heterogeneous populations trialled all contribute to the uncertainty. Larger studies, with less risk of bias from patient selection, blinding of outcomes assessors, reporting of all outcomes measured and with registration of study protocols, are required to settle the question.

Association of interleukin-8 and neutrophils with nasal symptom severity during acute respiratory infection

Using a large data set (n = 811), the relationship between acute respiratory infection illness severity and inflammatory biomarkers was investigated to determine whether certain symptoms are correlated more closely than others with the inflammatory biomarkers, interleukin‐8 (IL‐8) and nasal neutrophils. Participants with community acquired acute respiratory infection underwent nasal lavage for IL‐8 and neutrophil testing, in addition to multiplex polymerase chain reaction (PCR) methods for the detection and identification of respiratory viruses. Information about symptoms was obtained throughout the duration of the illness episode using the well‐validated Wisconsin Upper Respiratory Symptom Survey (WURSS‐21). Global symptom severity was calculated by the area under the curve (AUC) plotting duration versus WURSS total. Of the specimens tested, 56% were positively identified for one or more of nine different respiratory viruses. During acute respiratory infection illness, both IL‐8 and neutrophils positively correlate with AUC (r_s = 0.082, P = 0.022; r_s = 0.080, P = 0.030). IL‐8 and neutrophils correlate with nasal symptom severity: runny nose (r = 0.13, P = < 0.00001; r = 0.18, P = < 0.003), plugged nose (r = 0.045, P = 0.003; r = 0.14, P = 0.058), and sneezing (r = −0.02, P = < 0.0001; r = −0.0055, P = 0.31). Neutrophils correlate with some quality of life measures such as sleeping well (r = 0.15, P = 0.026). Thus, the study demonstrates that IL‐8 and neutrophils are correlated with severity of nasal symptoms during acute respiratory infection. Further research is necessary to determine if the concentration of these or other biomarkers can predict the overall duration and severity of acute respiratory infection illness. J. Med. Virol. 87:330–337, 2015. © 2014 Wiley Periodicals, Inc.

Mindfulness may both moderate and mediate the effect of physical fitness on cardiovascular responses to stress: a speculative hypothesis

The psychological construct of mindfulness refers to an awareness that emerges by intentionally paying attention to the present experience in a non-judgmental or evaluative way. This particular quality of awareness has been associated to several indicators of physical and psychological health, and can be developed using mindfulness-based interventions (MBIs), and therefore MBIs have been successfully applied as preventive and complementary interventions and therapies in medicine and psychology. Together with quiet sitting and lying meditation practices, mindful physical exercises such as “mindful walking” and “mindful movement” are key elements in MBIs and couple muscular activity with an internally directed focus, improving interoceptive attention to bodily sensations. In addition, MBIs seem to share similar mechanisms with physical fitness (PF) by which they may influence cardiovascular responses to stress. Based on these facts, it is feasible to raise the question of whether physical training itself may induce the development of that particular quality of awareness associated with mindfulness, or if one's dispositional mindfulness (DM) (the tendency to be more mindful in daily life) could moderate the effects of exercise on cardiovascular response to stress. The role of mindfulness as a mediator or moderator of the effect of exercise training on cardiovascular responses to stress has barely been studied. In this study, we have hypothesized pathways (moderation and mediation) by which mindfulness could significantly influence the effects of PF on cardiovascular responses to stress and discussed potential practical ways to test these hypotheses.