Reversible Airflow Obstruction Predicts Future Chronic Obstructive Pulmonary Disease Development in the SPIROMICS Cohort: An Observational Cohort Study.

Rationale: Chronic obstructive pulmonary disease (COPD) is defined by fixed spirometric ratio, FEV1/FVC < 0.70 after inhaled bronchodilators. However, the implications of variable obstruction (VO), in which the prebronchodilator FEV1/FVC ratio is less than 0.70 but increases to 0.70 or more after inhaled bronchodilators, have not been determined. Objectives: We explored differences in physiology, exacerbations, and health status in participants with VO compared with reference participants without obstruction. Methods: Data from the SPIROMICS (Subpopulations and Intermediate Outcome Measures in COPD Study) cohort were obtained. Participants with VO were compared with reference participants without obstruction. Measurements and Main Results: We assessed differences in baseline radiographic emphysema and small airway disease at study entry, baseline, and change in lung function by spirometry, functional capacity by 6-minute walk, health status using standard questionnaires, exacerbation rates, and progression to COPD between the two groups. All models were adjusted for participant characteristics, asthma history, and tobacco exposure. We assessed 175 participants with VO and 603 reference participants without obstruction. Participants with VO had 6.2 times the hazard of future development of COPD controlling for other factors (95% confidence interval, 4.6-8.3; P < 0.001). Compared with reference participants, the VO group had significantly lower baseline pre- and post-bronchodilator (BD) FEV1, and greater decline over time in post-BD FEV1, and pre- and post-BD FVC. There were no significant differences in exacerbations between groups. Conclusions: Significant risk for future COPD development exists for those with pre- but not post-BD airflow obstruction. These findings support consideration of expanding spirometric criteria defining COPD to include pre-BD obstruction. Clinical trial registered with www.clinicaltrials.gov (NCT01969344).

Longitudinal Follow-Up of Participants With Tobacco Exposure and Preserved Spirometry.

Importance: People who smoked cigarettes may experience respiratory symptoms without spirometric airflow obstruction. These individuals are typically excluded from chronic obstructive pulmonary disease (COPD) trials and lack evidence-based therapies. Objective: To define the natural history of persons with tobacco exposure and preserved spirometry (TEPS) and symptoms (symptomatic TEPS). Design, Setting, and Participants: SPIROMICS II was an extension of SPIROMICS I, a multicenter study of persons aged 40 to 80 years who smoked cigarettes (>20 pack-years) with or without COPD and controls without tobacco exposure or airflow obstruction. Participants were enrolled in SPIROMICS I and II from November 10, 2010, through July 31, 2015, and followed up through July 31, 2021. Exposures: Participants in SPIROMICS I underwent spirometry, 6-minute walk distance testing, assessment of respiratory symptoms, and computed tomography of the chest at yearly visits for 3 to 4 years. Participants in SPIROMICS II had 1 additional in-person visit 5 to 7 years after enrollment in SPIROMICS I. Respiratory symptoms were assessed with the COPD Assessment Test (range, 0 to 40; higher scores indicate more severe symptoms). Participants with symptomatic TEPS had normal spirometry (postbronchodilator ratio of forced expiratory volume in the first second [FEV1] to forced vital capacity >0.70) and COPD Assessment Test scores of 10 or greater. Participants with asymptomatic TEPS had normal spirometry and COPD Assessment Test scores of less than 10. Patient-reported respiratory symptoms and exacerbations were assessed every 4 months via phone calls. Main Outcomes and Measures: The primary outcome was assessment for accelerated decline in lung function (FEV1) in participants with symptomatic TEPS vs asymptomatic TEPS. Secondary outcomes included development of COPD defined by spirometry, respiratory symptoms, rates of respiratory exacerbations, and progression of computed tomographic-defined airway wall thickening or emphysema. Results: Of 1397 study participants, 226 had symptomatic TEPS (mean age, 60.1 [SD, 9.8] years; 134 were women [59%]) and 269 had asymptomatic TEPS (mean age, 63.1 [SD, 9.1] years; 134 were women [50%]). At a median follow-up of 5.76 years, the decline in FEV1 was -31.3 mL/y for participants with symptomatic TEPS vs -38.8 mL/y for those with asymptomatic TEPS (between-group difference, -7.5 mL/y [95% CI, -16.6 to 1.6 mL/y]). The cumulative incidence of COPD was 33.0% among participants with symptomatic TEPS vs 31.6% among those with asymptomatic TEPS (hazard ratio, 1.05 [95% CI, 0.76 to 1.46]). Participants with symptomatic TEPS had significantly more respiratory exacerbations than those with asymptomatic TEPS (0.23 vs 0.08 exacerbations per person-year, respectively; rate ratio, 2.38 [95% CI, 1.71 to 3.31], P < .001). Conclusions and Relevance: Participants with symptomatic TEPS did not have accelerated rates of decline in FEV1 or increased incidence of COPD vs those with asymptomatic TEPS, but participants with symptomatic TEPS did experience significantly more respiratory exacerbations over a median follow-up of 5.8 years.

Use of a Wearable Biosensor to Study Heart Rate Variability in Chronic Obstructive Pulmonary Disease and Its Relationship to Disease Severity.

The purpose of this study was to explore the relationships between heart rate variability (HRV) and various phenotypic measures that relate to health and functional status in chronic obstructive pulmonary disease (COPD), and secondly, to demonstrate the feasibility of ascertaining HRV via a chest-worn wearable biosensor in COPD patients. HRV analysis was performed using SDNN (standard deviation of the mean of all normal R-R intervals), low frequency (LF), high frequency (HF), and LF/HF ratio. We evaluated the associations between HRV and COPD severity, class of bronchodilator therapy prescribed, and patient reported outcomes. Seventy-nine participants with COPD were enrolled. There were no differences in SDNN, HF, and LF/HF ratio according to COPD severity. The SDNN in participants treated with concurrent beta-agonists and muscarinic antagonists was lower than that in other participants after adjusting heart rate (beta coefficient -3.980, p = 0.019). The SDNN was positively correlated with Veterans Specific Activity Questionnaire (VSAQ) score (r = 0.308, p = 0.006) and handgrip strength (r = 0.285, p = 0.011), and negatively correlated with dyspnea by modified Medical Research Council (mMRC) questionnaire (r = -0.234, p = 0.039), health status by Saint George's Respiratory Questionnaire (SGRQ) (r = -0.298, p = 0.008), symptoms by COPD Assessment Test (CAT) (r = -0.280, p = 0.012), and BODE index (r = -0.269, p = 0.020). When measured by a chest-worn wearable device, reduced HRV was observed in COPD participants receiving inhaled beta-sympathomimetic agonist and muscarinic antagonists. HRV was also correlated with various health status and performance measures.

A Multidomain Approach to Assessing the Convergent and Concurrent Validity of a Mobile Application When Compared to Conventional Methods of Determining Body Composition.

Determining body composition via mobile application may circumvent limitations of conventional methods. However, the accuracy of many technologies remains unknown. This investigation assessed the convergent and concurrent validity of a mobile application (LS) that employs 2-dimensional digital photography (LS2D) and 3-dimensional photonic scanning (LS3D). Measures of body composition including circumferences, waist-to-hip ratio (WHR), and body fat percentage (BF%) were obtained from 240 healthy adults using LS and a diverse set of conventional methods-Gulick tape, bioelectrical impedance analysis (BIA), and skinfolds. Convergent validity was consistently high-indicating these methods vary proportionally and can thus reliably detect changes despite individual measurement differences. The span of the Limits of Agreement (LoA) using LS were comparable to the LoA between conventional methods. LS3D exhibited high agreement relative to Gulick tape in the measurement of WHR, despite poor agreement with individual waist and hip circumferences. In BF%, LS2D exhibited high agreement with BIA and skinfold methods, whereas LS3D demonstrated low agreement. Interestingly, the low inferred bias between LS3D and DXA using existing data suggests that LS3D may have high agreement with dual-energy x-ray absorptiometry. Overall, the suitability of LS2D and LS3D to replace conventional methods must be based on an individual user's criteria.

Effect of altering breathing frequency on maximum voluntary ventilation in healthy adults.

BACKGROUND: Compared to other pulmonary function tests, there is a lack of standardization regarding how a maximum voluntary ventilation (MVV) maneuver is performed. Specifically, little is known about the variation in breathing frequency (fR) and its potential impact on the accuracy of test results. This study examines the effect of several preselected values for fR and one self-selected fR (fRself) on MVV. METHODS: Ten participants performed MVV maneuvers at various fR values, ranging from 50 to 130 breaths·min- 1 in 10 breaths·min- 1 intervals and at one fRself. Three identical trials with 2-min rest periods were conducted at each fR, and the sequence in which fR was tested was randomized. Ventilation and related parameters were measured directly by gas exchange analysis via a metabolic measurement system. RESULTS: A third-order polynomial regression analysis showed that MVV = - 0.0001(fR)3 + 0.0258(fR)2-1.38(fR) + 96.9 at preselected fR and increased up to approximately 100 breaths·min- 1 (r2 = 0.982, P < 0.001). Paired t-tests indicated that average MVV values obtained at all preselected fR values, but not fRself, were significantly lower than the average maximum value across all participants. A linear regression analysis revealed that tidal volume (VT) = - 2.63(MVV) + 300.4 at preselected fR (r2 = 0.846, P < 0.001); however, this inverse relationship between VT and MVV did not remain true for the self-selected fR. The VT obtained at this fR (90.9 ± 19.1% of maximum) was significantly greater than the VT associated with the most similar MVV value (at a preselected fR of 100 breaths·min- 1, 62.0 ± 10.4% of maximum; 95% confidence interval of difference: (17.5, 40.4%), P < 0.001). CONCLUSIONS: This study demonstrates the shortcomings of the current lack of standardization in MVV testing and establishes data-driven recommendations for optimal fR. The true MVV was obtained with a self-selected fR (mean ± SD: 69.9 ± 22.3 breaths·min- 1) or within a preselected fR range of 110-120 breaths·min- 1. Until a comprehensive reference equation is established, it is advised that MVV be measured directly using these guidelines. If an individual is unable to perform or performs the maneuver poorly at a self-selected fR, ventilating within a mandated fR range of 110-120 breaths·min- 1 may also be acceptable.

Exercise responses in patients with chronically high creatine kinase levels.

INTRODUCTION: Elevated serum creatine kinase (CK) is often taken to reflect muscle disease, but many individuals have elevated CK without a specific diagnosis. How elevated CK reflects muscle metabolism during exercise is not known. METHODS: Participants (46 men, 48 women) underwent incremental exercise testing to assess aerobic performance, cardiovascular response, and ventilatory response. Serum lactate, ammonia, and CK were measured at rest, 4 minutes into exercise, and 2 minutes into recovery. RESULTS: High-CK and control subjects demonstrated similar aerobic capacities and cardiovascular responses to incremental exercise. Those with CK ≥ 300 U/L exhibited significantly higher lactate and ammonia levels after maximal exercise, together with increased ventilatory responses, whereas those with CK ≥200 U/L but ≤ 300 U/L did not. CONCLUSIONS: We recommend measurement of lactate and ammonia profiles during a maximal incremental exercise protocol to help identify patients who warrant muscle biopsy to rule out myopathy. Muscle Nerve 56: 264-270, 2017.

Exploratory Study of Heart Rate Variability and Sleep among Emergency Medical Services Shift Workers.

OBJECTIVES: To characterize the continuity and duration of sleep, and to measure nocturnal cardiac autonomic balance via heart rate variability (HRV) in a group of emergency medical technicians (EMTs) on and off duty. METHODS: Fourteen EMTs completed an online, daily sleep log that recorded total sleep duration, bedtime, rise time, and the number of alarms that caused awakening. HRV was captured using a physiological status monitor (PSM) affixed to a chest strap during sleep. RESULTS: For the 7-day trial, each of the 14 EMTs logged three work days (WDs) and four non-work days (NWDs). They reported sleeping significantly fewer hours per night on WDs (6.4 ± 2.1) than on NWDs (7.9 ± 0.5; P < 0.05), and experienced more sleep disruptions on WDs (4.4 ± 2.8) than on NWDs (1.3 ± 2.2; P < 0.001) as measured by the number of alarms. Global and vagal indices of HRV during sleep were significantly reduced during WDs (Standard Deviation of Normal R-R Intervals (SDNN) = 43.4 ± 2.0 ms and High Frequency (HF) = 24.3 ± 1.2 ms2) when compared to NWDs (SDNN = 61.1 ± 1.0 ms and HF = 42.7 ± 1.5 ms2; P < 0.001). CONCLUSION: EMTs who worked 24-hour shifts had shorter, more fragmented sleep associated with greater cumulative exposure to increased sympathetic and decreased parasympathetic activity as measured via sleep HRV. These changes in cardiac autonomic tone constitute one plausible pathway through which sleep deprivation may increase risk for cardiovascular disease.

A Systematic Method to Detect the Metabolic Threshold from Gas Exchange during Incremental Exercise.

Incremental exercise consists of three domains of exercise intensity demarcated by two thresholds. The first of these thresholds, derived from gas exchange measurements, is defined as the metabolic threshold (V̇O2θ) above which lactate accumulates. Correctly and reliably identified, V̇O2θ is a non-invasive, sub-maximal marker of aerobic function with practical value. This investigation compared variability in selection of V̇O2θ among interpreters with different levels of experience as well as from auto-detection algorithms employed by a commercially available metabolic cart (MC). Ten healthy young men performed three replicates of incremental cycle exercise during which gas exchange measurements were collected breath-by-breath. Two experienced interpreters (E) and four novice interpreters (N) determined V̇O2θ from plots of specific response variables. Interpreters noted methods used and confidence in their selections. V̇O2θ was automatically determined by the MC. Interclass correlations indicated that E agreed with each other (mean difference, 21 mL·min-1) and with the MC (23 mL·min-1), but not with N (-664 to 364 mL·min-1); N did not agree among themselves. Despite good overall agreement between E and MC, differences >500 mL·min-1 were seen in 50% of individual cases. N expressed unduly higher confidence and used different V̇O2θ selection strategies compared with E. Experience and use of a systematic approach is essential for correctly identifying V̇O2θ. Current guidelines for exercise testing and interpretation do not include recommendations for such an approach. Data from this study suggests that this may be a serious shortcoming. Until an alternative schema for V̇O2θ detection is developed prospectively, strategies based on the present study will give practitioners a systematic and consistent approach to threshold detection.

Reverse fiber type disproportion: A distinct metabolic myopathy.

INTRODUCTION: In this investigation we characterized the physiological and metabolic responses to incremental exercise in 13 subjects with a predominance of type II fibers on muscle biopsy. METHODS: Subjects underwent incremental exercise testing with measures of maximum oxygen uptake ( V˙O2 max), maximum heart rate (fc max), chronotropic index (fc / V˙O2 slope), maximum ventilation ( V˙emax), blood lactate, ammonia, and creatine kinase (CK) levels. Muscle fiber type was determined by myosin ATPase histochemistry. RESULTS: Muscle biopsies showed more type II fibers (75%) in subjects compared with normal individuals (P < 0.01). Subjects exhibited normal V˙O2 max and end-exercise lactate, whereas ammonia and CK levels at maximum exercise were significantly higher. CONCLUSIONS: Subjects with type II muscle fiber predominance exhibited exaggerated increases in ammonia and elevated CK levels during exercise. Predominance of type II fibers on muscle biopsy is the opposite finding of congenital fiber type disproportion; we suggest these patients be referred to as having "reverse fiber type disproportion." Muscle Nerve 54: 86-93, 2016.

Validation of Biofeedback Wearables for Photoplethysmographic Heart Rate Tracking.

The purpose of this study was to examine the validity of HR measurements by two commercial-use activity trackers in comparison to ECG. Twenty-four healthy participants underwent the same 77-minute protocol during a single visit. Each participant completed an initial rest period of 15 minutes followed by 5 minute periods of each of the following activities: 60W and 120W cycling, walking, jogging, running, resisted arm raises, resisted lunges, and isometric plank. In between each exercise task was a 5-minute rest period. Each subject wore a Basis Peak (BPk) on one wrist and a Fitbit Charge HR (FB) on the opposite wrist. Criterion measurement of HR was administered by 12-lead ECG. Time synced data from each device and ECG were concurrently and electronically acquired throughout the entire 77-minute protocol. When examining data in aggregate, there was a strong correlation between BPk and ECG for HR (r = 0.92, p < 0.001) with a mean bias of -2.5 bpm (95% LoA 19.3, -24.4). The FB demonstrated a moderately strong correlation with ECG for HR (r = 0.83, p < 0.001) with an average mean bias of -8.8 bpm (95% LoA 24.2, -41.8). During physical efforts eliciting ECG HR > 116 bpm, the BPk demonstrated an r = 0.77 and mean bias = -4.9 bpm (95% LoA 21.3, -31.0) while the FB demonstrated an r = 0.58 and mean bias = -12.7 bpm (95% LoA 28.6, -54.0). The BPk satisfied validity criteria for HR monitors, however showed a marginal decline in accuracy with increasing physical effort (ECG HR > 116 bpm). The FB failed to satisfy validity criteria and demonstrated a substantial decrease in accuracy during higher exercise intensities.

Inter- and intra-rater agreement of static posture analysis using a mobile application.

[Purpose] To determine the intra- and inter-rater agreement of a mobile application, PostureScreen Mobile® (PSM), that assesses static standing posture. [Subjects and Methods] Three examiners with different levels of experience of assessing posture, one licensed physical therapist and two untrained undergraduate students, performed repeated postural assessments of 10 subjects, fully clothed or minimally clothed, using PSM on two nonconsecutive days. Anterior and right lateral images were captured and seventeen landmarks were identified on them. Intraclass correlation coefficients (ICCs) were calculated for each of 13 postural measures to evaluate inter-rater agreement on the first visit (fully or minimally clothed), as well as intra-rater agreement between the first and second visits (minimally clothed). [Results] Eleven postural measures were ultimately analyzed for inter- and intra-rater agreement. Inter-rater agreement was almost perfect (ICC≥0.81) for four measures and substantial (0.60

Predictors of depression outcomes among abstinent methamphetamine-dependent individuals exposed to an exercise intervention.

BACKGROUND AND OBJECTIVES: This paper expands on a study investigating depression outcomes in response to an 8-week exercise intervention among methamphetamine (MA) dependent individuals in early recovery. METHODS: A total of 135 MA-dependent individuals enrolled in residential treatment were randomly assigned to either a structured exercise intervention or a structured health education control group. Both groups were similar in format: 60-minute sessions, offered three times a week over an 8-week study period. RESULTS: Results showed that at the 8-week trial endpoint, participants randomized to the exercise intervention showed significantly greater reduction in depression symptom scores than participants randomized to the health education group, and that participants who attended the greatest number of exercise sessions derived the greatest benefit. This paper further analyzes study data to uncover individual predictors of depression response to exercise and finds that among participants randomized to exercise treatment, individuals with the most severe medical, psychiatric, and addiction disease burden at baseline showed the most significant improvement in depressive symptoms by study endpoint. CONCLUSIONS: Our findings suggest that exercise in moderate dose is effective at treating depressive symptoms in individuals in early recovery from addiction, and furthermore, that treatment with exercise appears to be particularly beneficial to individuals who suffer from severe medical, psychiatric, and addictive disorders.

Deployment of remote advanced electrocardiography for improved cardiovascular risk assessment in career firefighters.

INTRODUCTION: Firefighters perform strenuous muscular work while wearing heavy, encapsulating personal protective equipment in high temperature environments, under chaotic and emotionally stressful conditions. These factors can precipitate sudden cardiac events in firefighters with underlying cardiovascular disease. The purpose of this pilot study was to deploy and explore the feasibility of the resting "advanced" 12-lead electrocardiogram (A-ECG) as a remote firefighter risk assessment tool for improved assessment of cardiac risk. MATERIALS AND METHODS: Conventional 12-lead resting electrocardiograms (ECGs) were collected for 5 min by using high-fidelity PC-based ECG hardware and software while subjects (n=21) rested comfortably. Raw data from the ECG system were securely transported via a secure network to a server where they were archived and processed. Authorized personnel performed both conventional ECG and A-ECG analyses from each digital recording, generating A-ECG "scores" in a blinded fashion. A separate cohort of firefighters (n=6) was trained to administer the A-ECG and rated the system's usability and frequency of technical problems. RESULTS: Of the 21 uniformed personnel who completed testing, only 1 had a positive A-ECG score for coronary artery disease, which was subsequently confirmed by a cardiologist. All other subjects were classified as healthy by A-ECG. Firefighters trained to administer the A-ECG responded favorably in rating the usability of the system. CONCLUSIONS: We have demonstrated that a new technology, A-ECG, can be deployed for remote firefighter risk assessment being performed by firefighters themselves and interpreted centrally. This simple, time- and cost-effective approach can help identify individuals potentially at increased risk for line-of-duty death due to underlying cardiovascular disease.

Effect of supervised, periodized exercise training vs. self-directed training on lean body mass and other fitness variables in health club members.

Conventional wisdom suggests that exercise training with a personal trainer (PTr) is more beneficial for improving health-related fitness than training alone. However, there are no published data that confirm whether fitness club members who exercise with a PTr in the fitness club setting obtain superior results compared with self-directed training. We hypothesized that club members randomized to receive an evidence-based training program would accrue greater improvements in lean body mass (LBM) and other fitness measures than members randomized to self-training. Men, aged 30-44 years, who were members of a single Southern California fitness club were randomized to exercise with a PTr administering a nonlinear periodized training program (TRAINED, N = 17) or to self-directed training (SELF, N = 17); both groups trained 3 days per week for 12 weeks. Lean body mass was determined by dual-energy x-ray absorptiometry. Secondary outcomes included muscle strength 1 repetition maximum (1RM), leg power (vertical jump), and aerobic capacity (V[Combining Dot Above]O2max). TRAINED individuals increased LBM by 1.3 (0.4) kg, mean (SEM) vs. no change in SELF, p = 0.029. Similarly, significantly greater improvements were seen for TRAINED vs. SELF in chest press strength (42 vs. 19%; p = 0.003), peak leg power (6 vs. 0.6%; p < 0.0001), and V[Combining Dot Above]O2max (7 vs. -0.3%; p = 0.01). Leg press strength improved 38 and 25% in TRAINED and SELF, respectively (p = 0.14). We have demonstrated for the first time in a fitness club setting that members whose training is directed by well-qualified PTrs administering evidence-based training regimens achieve significantly greater improvements in LBM and other dimensions of fitness than members who direct their own training.

Firefighter health and fitness assessment: a call to action.

Sudden cardiac deaths experienced by firefighters in the line of duty account for the largest proportion of deaths annually. Several fire service standards for fitness and wellness have been recommended but currently only 30% of U.S. fire departments are implementing programs for this purpose. The Department of Homeland Security Science and Technology Directorate has initiated the Physiological Health Assessment System for Emergency Responders (PHASER) program aiming to reduce these line-of-duty deaths through an integration of medical science and sensor technologies. Confirming previous reports, PHASER comprehensive risk assessment has identified lack of physical fitness with propensity for overexertion as a major modifiable risk factor. We sought to determine if current levels of fitness and cardiovascular disease (CVD) risk factors in a contemporary cohort of firefighters were better than those reported over the past 30 years. Fifty-one firefighters from a Southern California department were characterized for physical fitness and CVD risk factors using standard measures. Overall, physical fitness and risk factors were not different from previous reports of firefighter fitness and most subjects did not achieve recommended fitness standards. Considering the lack of widespread implementation of wellness/fitness programs in the U.S. fire service together with our findings that low physical fitness and the presence of CVD risk factors persist, we issue a call to action among health and fitness professionals to assist the fire service in implementing programs for firefighters that improve fitness and reduce CVD risk factors. Fitness professionals should be empowered to work with fire departments lending their expertise to guide programs that achieve these objectives, which may then lead to reduced incidence of sudden cardiac death or stroke.

Evaluation of a wearable physiological status monitor during simulated fire fighting activities.

A physiological status monitor (PSM) has been embedded in a fire-resistant shirt. The purpose of this research study was to examine the ability of the PSM-shirt to accurately detect heart rate (HR) and respiratory rate (RR) when worn under structural fire fighting personal protective equipment (PPE) during the performance of various activities relevant to fire fighting. Eleven healthy, college-aged men completed three activities (walking, searching/crawling, and ascending/descending stairs) that are routinely performed during fire fighting operations while wearing the PSM-shirt under structural fire fighting PPE. Heart rate and RR recorded by the PSM-shirt were compared to criterion values measured concurrently with an ECG and portable metabolic measurement system, respectively. For all activities combined (overall) and for each activity, small differences were found between the PSM-shirt and ECG (mean difference [95% CI]: overall: -0.4 beats/min [-0.8, -0.1]; treadmill: -0.4 beats/min [-0.7, -0.1]; search: -1.7 beats/min [-3.1, -.04]; stairs: 0.4 beats/min [0.04, 0.7]). Standard error of the estimate was 3.5 beats/min for all tasks combined and 1.9, 5.9, and 1.9 beats/min for the treadmill walk, search, and stair ascent/descent, respectively. Correlations between the PSM-shirt and criterion heart rates were high (r = 0.95 to r = 0.99). The mean difference between RR recorded by the PSM-shirt and criterion overall was 1.1 breaths/min (95% CI: -1.9 to -0.4). The standard error of the estimate for RR ranged from 4.2 breaths/min (treadmill) to 8.2 breaths/min (search), with an overall value of 6.2 breaths/min. These findings suggest that the PSM-shirt provides valid measures of HR and useful approximations of RR when worn during fire fighting duties.

Efficacy of a 6-week Novel Exergaming Intervention Guided by Heart Rate Zones on Aerobic Performance in Children with Fetal Alcohol Spectrum Disorder and Attention-deficit/Hyperactivity Disorder: A Feasibility Study.

The purpose of this study was to determine the feasibility of a novel exergaming intervention guided by heart rate zones for children and adolescents with fetal alcohol spectrum disorder (FASD) and attention-deficit/hyperactivity disorder (ADHD). Eight study participants (6 females, 2 males, mean age= 11.4±1.4 years old) participated twice weekly over six weeks to complete twelve multimodal exergaming sessions. Participants significantly improved 6MWT from baseline to week 6 (575.4±55.0 m to 732.8±58.9 m; P<0.01), which conferred a 31% improvement in estimated VO2max (31.5±5.5 ml/kg/min to 40.9±5.9 ml/kg/min), respectively. There was an upward trend of the mean percentage of time spent in the intermediate HR zones over the course of the 6-week intervention. These findings may provide value to the field as they support the clinical utility and promising effects of cardiovascular improvement in children who engage in a compelling exergaming intervention. In doing so, this establishes a preliminary understanding of how to augment routine physical exercise through exergaming using visually targeted heart rate zones.

Bronchodilator Responsiveness in Tobacco-Exposed People With or Without COPD.

BACKGROUND: Bronchodilator responsiveness (BDR) in obstructive lung disease varies over time and may be associated with distinct clinical features. RESEARCH QUESTION: Is consistent BDR over time (always present) differentially associated with obstructive lung disease features relative to inconsistent (sometimes present) or never (never present) BDR in tobacco-exposed people with or without COPD? STUDY DESIGN AND METHODS: We retrospectively analyzed data from 2,269 tobacco-exposed participants in the Subpopulations and Intermediate Outcome Measures in COPD Study with or without COPD. We used various BDR definitions: change of ≥ 200 mL and ≥ 12% in FEV1 (FEV1-BDR), change in FVC (FVC-BDR), and change in in FEV1, FVC or both (ATS-BDR). Using generalized linear models adjusted for demographics, smoking history, FEV1 % predicted after bronchodilator administration, and number of visits that the participant completed, we assessed the association of BDR group: (1) consistent BDR, (2) inconsistent BDR, and (3) never BDR with asthma, CT scan features, blood eosinophil levels, and FEV1 decline in participants without COPD (Global Initiative for Chronic Obstructive Lung Disease [GOLD] stage 0) and the entire cohort (participants with or without COPD). RESULTS: Both consistent and inconsistent ATS-BDR were associated with asthma history and greater small airways disease (%parametric response mapping functional small airways disease) relative to never ATS-BDR in participants with GOLD stage 0 disease and the entire cohort. We observed similar findings using FEV1-BDR and FVC-BDR definitions. Eosinophils did not vary consistently among BDR groups. Consistent BDR was associated with FEV1 decline over time relative to never BDR in the entire cohort. In participants with GOLD stage 0 disease, both the inconsistent ATS-BDR group (OR, 3.20; 95% CI, 2.21-4.66; P < .001) and consistent ATS-BDR group (OR, 9.48; 95% CI, 3.77-29.12; P < .001) were associated with progression to COPD relative to the never ATS-BDR group. INTERPRETATION: Demonstration of BDR, even once, describes an obstructive lung disease phenotype with a history of asthma and greater small airways disease. Consistent demonstration of BDR indicated a high risk of lung function decline over time in the entire cohort and was associated with higher risk of progression to COPD in patients with GOLD stage 0 disease.

The Efficacy of an Immersive Virtual Reality Exergame Incorporating an Adaptive Cable Resistance System on Fitness and Cardiometabolic Measures: A 12-Week Randomized Controlled Trial.

Exergaming, combining elements of video game into the realm of exercise, has recently incorporated immersive virtual reality (IVR) with resistance training. Thirty-two participants (14 females, mean age = 24.3) were randomized to IVR or self-directed control group (SELF) and worked out thrice weekly for 12 weeks (for 36 sessions). The IVR group spent 14 fewer minutes per session (p < 0.001) while reporting the sessions "enjoyable'. Compared to SELF, the IVR group had significantly greater improvement in changes from baseline to post-training in upper-and-lower muscular strength (1-RM) and muscular endurance (85% 1-RM) (14.3 kg vs. 10.0 kg for 1-RM upper, 28.6 kg vs. 22.5 kg for 1-RM lower, 2.6 reps vs. 1.9 reps for 85% 1-RM of upper, 2.7 vs. 2.0 reps for 85% 1-RM of lower, all p < 0.001), peak leg power (1424 vs. 865 W, p < 0.001), body fat% (−3.7% vs. −1.9%, p < 0.001), heart rate variability (4.3 vs. 1.8 ms, p < 0.001), rVO2max (3.28 vs. 0.89 mL/min/kg, p < 0.001) with decreased systolic BP (−0.4 vs. −2.3 mmHg, p < 0.001), and level of perceived exertion during workouts (RPE 14 vs. 16, p < 0.001). With its high-paced and action-filled gaming coupled with superior fitness and cardiometabolic outcomes, this IVR exergaming platform should be considered as another exercise modality for performance and health-related training.

Effect of Real-Time Feedback on Power Output Using a Novel Smart-Resisted Sled Push.

Prior studies have demonstrated the beneficial effects of real-time data feedback (RTF) on athletic performance and motivation. Despite this evidence, the lack of practical means to implement RTF has hindered its widespread adoption. Recently, a smart-resisted sled push was developed to improve athletic power by utilizing electromagnetic motors as a resistance mechanism, coupled with an RTF display. Thirty healthy college-aged male football players were recruited in this randomized, crossover designed study to examine the efficacy of the RTF to improve power output. Participants were randomized into either group 1 (receiving RTF first then no RTF) or group 2 (receiving no RTF first then RTF) during six, 10-meter sled pushes with 3 min rest intervals. The first three pushes were set to an easier level (L1) and the last three were set to a resistance level twice that of the first three runs (L2). A one-month washout period was enforced. For trials 1-3 (L1) (p = 0.026, t = -2.34, ES = -0.428) and 4-6 (L2) (p = 0.035, t = -2.22, ES = -0.405), peak power output (the average peak power output over the course of trials 1-3 and 4-6) was greater in both groups when receiving RTF compared to no-RTF. These findings demonstrate the effectiveness of RTF in augmenting power output during performance training.