Respiratory Infection
Meditation and Exercise vs Common Cold An Ounce of Prevention and Pound of Cure?
Abstract and Commentary
By Nancy J. Selfridge, MD. Associate Professor, Integrated Medical Education, Ross University School of Medicine, Commonwealth of Dominica, West Indies. Dr. Selfridge reports no financial relationships relevant to this field of study.
Synopsis: Meditation and exercise interventions were shown to reduce the frequency, duration, and symptom severity of acute respiratory illness in adults aged 50 and older compared to a waitlist control group.
Source: Barrett B, et al. Meditation or exercise for preventing acute respiratory infection: A randomized controlled trial. Ann Fam Med 2012;10:337-346.
Non-influenza acute respiratory infection (ARI) is common, costly, and often debilitating. In research published in 2003, Fendrick et al estimated 500 million episodes of ARI per year in adults and children, with a total economic impact of $40 billion annually. Direct costs, estimated at $17 billion per year, included physician visits, laboratory costs, OTC medication use, and prescriptions. An estimated $22.5 billion in indirect costs were due to missed work days resulting from personal illness or providing care at home for a sick child.1 In a summary of mindfulness research, Greeson reported evidence that mindfulness training reduces negative emotion and perceived stress, both of which have been linked to increases in self-reported illness as well as viral shedding and elevated biomarkers of inflammation. In addition, mindfulness training has shown positive influence on antibody responses to influenza vaccine, reduced cortical levels in cancer patients, and trends toward normalized immune function in cancer and HIV patients.2 Epidemiological evidence suggests that moderate habitual exercise is associated with a 29% reduction in risk of succumbing to an upper respiratory tract infection compared to sedentary lifestyle.3 Based on existing evidence, Barrett et al designed this study to more robustly test the hypothesis that mindfulness meditation or moderate intensity exercise could reduce ARI incidence, duration, and severity.
A total of 154 adult participants were selected after community recruitment and screening, and randomly assigned to one of two active treatment groups or an observational control group. The active interventions consisted of either an 8-week mindfulness meditation course or an 8-week exercise program. The two interventions were matched in terms of total group contact time (eight 2½ hour weekly sessions), recommended home practice time (45 minutes per day), and location. The meditation intervention was based on the mindfulness-based stress reduction (MBSR) course created by Jon Kabat-Zinn at the University of Massachusetts,4 and all of the MBSR instructors were trained by Kabat-Zinn's group. The exercise program was designed by the physiology staff at the UW Health Sports Medicine Center and supervised by three licensed and experienced athletic trainers. The exercise program consisted of moderate-intensity sustained aerobic exercise using exercise equipment in the center or via brisk walking or jogging at home, approximately 420 minutes of exercise per week. Control group participants were offered meditation or exercise training, or a monetary equivalent at the end of the trial, which started in September and finished in May the following year.
The primary outcome was global severity for all ARI illness days from the time of consent until study exit, as measured by the Wisconsin Upper Respiratory Symptom Survey (WURSS-24), a validated instrument for assessing ARI symptom severity. To determine if a participant had an ARI during the study period, he or she had to meet predetermined criteria about number, severity, and duration of symptoms on questionnaires and the WURSS that had been distributed at the time of enrollment. All participants were contacted by telephone twice weekly starting post-intervention until the close of the study period to remind them to begin documenting ARI symptoms on these questionnaires as soon as they believed they might be getting a cold. Daily severity scores were collected as well as illness duration. Secondary outcome measures included scores on a variety of validated measures of self-reported physical and mental health, stress levels, exercise, and mindfulness. Missed days of work or school were documented as well as health care visits; however, use of OTC or prescription medications was not documented. In addition, a nasal wash was collected from all participants who developed ARI within 3 days of symptom onset and was analyzed for interleukin-8 and neutrophil count, markers for inflammation. Viral nucleic acid was analyzed for virus identification.
Of 154 participants, 82% were female, 94% were white, and the mean age was 59.3 years. One hundred forty-nine (96.7%) completed the trial. In the meditation group, there were 27 ARI episodes and 257 days of illness, and in the exercise group, there were 26 ARI episodes and 241 days of illness. The control group experienced 40 ARI episodes and 453 days of illness. Mean global severity scores were 144 for meditation, 248 for exercise, and 358 for control. The researchers chose P ≤ 0.025 as the cutoff for null hypothesis rejection to control for multiple testing, because increasing the number of tests performed on a study sample also increases the probability that any given test will yield misleading results that appear to be significant, but are not actually so. Thus, these values trended toward statistical significance compared to controls in number of illness days in the meditation group (P = 0.034) and exercise group (P = 0.032). Global severity scores were significantly lower for the meditation group compared to controls (P = 0.004), though not for the exercise group (P = 0.16). ARI-related missed days of work were significantly lower in the meditation group compared to the control group (P < 0.001) and trended toward statistical significance in the exercise group (P = 0.041). Nasal washings yielded similar results for all groups in terms of frequency and types of viruses isolated. Biomarkers for inflammation were similar in all groups except for slightly higher IL-8 levels in meditation participants.
Commentary
This study incidentally helps illustrate one of the problems with P values in clinical research. Though they are essential for helping to discern that the differences observed between groups are not solely due to chance, they don't tell us enough about measured effect sizes and the clinical significance of any differences between groups, parameters that must be examined and interpreted independently. Despite the fact that this study sample was not large enough to yield statistically significant P values for some outcomes, the size of the differences (effect sizes) in reduction of ARI illness in the treatment groups compared to controls was impressive and appears clinically significant. Incidence, duration, and global severity of ARI were 29%, 43%, and 31% lower in the exercise group and 33%, 43%, and 60% lower in the meditation group compared to controls. These differences and reported trends toward reduced ARI-related work absenteeism in this study suggest a clinically meaningful impact on ARI in terms of suffering and cost.
The treatment groups were divided into two cohorts, one group starting intervention at the beginning of the cold season in September (n = 94) and the other starting the following January (n = 60). Study exit was the following May; thus, the January groups were not followed through a complete winter-spring cold and influenza season, somewhat limiting interpretation of results. Due to the nature of the behavioral interventions, participants could not be blinded to their treatments and might be subject to self-reporting bias. However, the authors argue that self-report bias is unlikely, given the fact that scores on the secondary outcome measures of self-reported psychosocial health really showed no improvement over the course of the study. There was no control for group effect, the influence that merely participating in a group activity may have on outcomes, as the control group was observational and did not meet at any time as a group during the study. Furthermore, being predominantly female and white, the study sample was not representative of the U.S. population.
Nonetheless, this is an impressively and carefully designed study with intriguing results. This is the first randomized control study to assess the effects of mindfulness meditation training on ARI, the first to use a validated outcome measure to assess effects of exercise on ARI, and the first to compare two active intervention groups with an observational control. The biometric measures of inflammatory markers and viral identification are an additional strength. Addressing the limitations in this study in future research is urgently needed because of the potential public health impact of reducing the suffering and costs from ARI implied in this study. Both mindfulness meditation practice and exercise have multiple documented physical and mental health benefits with few risks. Though we are far from incorporating meditation and exercise into clinical guidelines for ARI prevention based on current research, mentioning these interventions as potentially helpful for adult patients predisposed to respiratory infections can certainly be encouraged while awaiting further research data.
References
1. Fendrick M, et al. The economic burden of non-influenza-related viral respiratory tract infection in the United States. Arch Intern Med 2003;163:487-494.
2. Greeson J. Mindfulness research update: 2008. Complement Health Pract Rev 2009;14:10-18.
3. Gleeson M. Immune function in sport and exercise. J Appl Physiol 2007;103:693-699.
4. Kabat-Zinn J. Full Catastrophe Living: Using the Wisdom of Your Body and Mind to Face Stress, Pain and Illness. New York, NY: Bantam Dell; 1990.
Meditation and exercise interventions were shown to reduce the frequency, duration, and symptom severity of acute respiratory illness in adults aged 50 and older compared to a waitlist control group.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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