Increasing Health Behaviors and Psychological Measures with an Adapted Version of the ACCELERATION Program.

BACKGROUND: Recent evidence highlights the importance of interventions tackling physical inactivity and unhealthy eating in lower-income countries. The purpose of this study was to examine the effectiveness of the Canadian ACCELERATION lifestyle program adapted to Brazilians. The main outcomes of the study were changes in the engagement in weekly moderate-to-vigorous physical activity (MVPA) and in the daily consumption of fruits/vegetables. METHODS: The adapted intervention consisted of a 12-week quasi-randomized controlled trial delivered through email. The data from the original Canadian experimental group (CE, n = 194) and the two groups of Portuguese-speaking Brazilians living in Canada in the adapted program - Brazilian experimental (BE, n = 41) and Brazilian control (BC, n = 35) - were assessed at baseline and post-intervention. The data of the 270 participants were analyzed using two-way repeated measures factorial ANCOVA (group x time) for ratio variables and Chi-square and McNemar tests for the categorical variables. RESULTS: The BE group had a significant increase in MVPA (mean difference, 95% CI: 86.3, 38.1-134.4 min/week) and fruits/vegetables intake (3.2, 1.4-5.1 servings/day) after the intervention (both p < 0.001). The proportion of participants engaging in ≥ 150 min of MVPA increased from 4.9% to 73.2%, while adoption of a healthy diet increased from 4.9% to 53.7% in the BE group (both p < 0.001). The CE group also improved on these variables (p < 0.05) with no difference vs the BE group (p > 0.05), whereas BC did not show changes (p > 0.05). CONCLUSION: The Brazilian version of the ACCELERATION program effectively promoted positive health behavior changes in its participants and has the potential to contribute to the fight against risk factors for chronic diseases in Brazilians.

Affective Response to Exercise and Affective Judgments as Predictors of Physical Activity Intention and Behavior among New Mothers in their first 6-Months Postpartum.

BACKGROUND: Understanding the predictors of moderate to vigorous physical activity (MVPA) during early postpartum is important to improve promotion efforts. Affect-related constructs are key predictors of MVPA but have limited research in mothers during the postpartum period. PURPOSE: To examine two affect-related constructs (affective response to exercise and affective judgments) as predictors of MVPA intention and behavior across three months, among a sample of new mothers. METHODS: Participants were 105 mothers (M age = 30.64 years; SD = 3.93) who completed measures during postpartum at 2-months post-birth of their first child. The affective response to exercise (assessed at baseline [2-months postpartum] during a submaximal treadmill test), affective judgments and intention (baseline, 6-weeks after baseline), and MVPA (baseline, 6- and 12-weeks after baseline) were assessed via self-report. RESULTS: Path analysis, using ordinary least squares regression, showed that the affective response during exercise was a significant predictor of intention (baseline, 6-weeks), as well as change in intention from baseline to 6-weeks. By contrast, affective judgments predicted intention at 6-weeks, but not at baseline or in the change model. Past MVPA did not moderate these findings, although the affective response during exercise also had a significant indirect effect on MVPA through intention at 6-weeks and 12-weeks. CONCLUSIONS: Interventions targeting women's affective response during exercise may be important during postpartum, perhaps through self-paced physical activity guidance. Affective judgments may not be predictive of MVPA, in part due to unanticipated changes during early postpartum leading to inaccurate expectations of the physical activity experience.

Understanding the predictors of moderate to vigorous physical activity (MVPA) during early postpartum is important to improve promotion efforts. Affect-related constructs are key predictors of MVPA but have limited research in mothers during the postpartum period. The purpose of this study was examine two affect-related constructs (affective response to exercise and affective judgments) as predictors of MVPA intention and behavior across three months, among a sample of new mothers. Participants were 105 mothers who completed measures of affective response to exercise (assessed at 2 months postpartum during a sub-maximal treadmill test), affective judgments and intention (2 months postpartum, and 6-weeks after), and MVPA (2 months postpartum, 6- and 12-weeks after). The affective response during exercise was a significant predictor of intention as well as change in intention over time. By contrast, affective judgments was a less reliable predictor across the study. Interventions targeting women's affective response during exercise may be important during postpartum, perhaps through self-paced physical activity guidance. Affective judgments may not be predictive of MVPA, in part due to unanticipated changes during early postpartum leading to inaccurate expectations of the physical activity experience.

Association between physical activity level and cardiovascular risk factors in adolescents living with type 1 diabetes mellitus: a cross-sectional study.

BACKGROUND: Type 1 diabetes mellitus (T1DM) is associated with an increased risk for cardiovascular disease (CVD) related morbidity and premature mortality. Regular physical activity plays an important role in the primary and secondary prevention of CVD, improving overall health and wellbeing. Previous observational studies have examined the associations between self-reported physical activity and CVD risk factors in largely adult Caucasian populations. However, limited work has evaluated the relationship between objectively measured physical activity and CVD risk factors in other ethnicities, particularly Chinese youth living with T1DM. METHODS: This cross-sectional study assessed CVD risk factors, physical activity, and aerobic fitness (and their associations) in Chinese youth living with T1DM (n = 48) and peers (n = 19) without T1DM. Primary outcomes included blood pressure, lipid profiles, and physical activity (accelerometry). Statistical differences between groups were determined with chi-square, independent-samples t-tests, or analysis of covariance. The associations between aerobic fitness, daily physical activity variables, and CVD risk factors were assessed with univariate and multivariate linear regression analyses. RESULTS: Results were summarized using means and standard deviation (SD) for normally distributed variables and medians and 25-75th quartile for non-normally distributed variables. In comparison to peers without diabetes, youth living with T1DM showed higher levels of total cholesterol (3.14 ± 0.67 vs. 4.03 ± 0.81 mmol·L-1, p = 0.001), low-density lipoprotein cholesterol (1.74 ± 0.38 vs. 2.31 ± 0.72 mmol·L-1, p = 0.005), and triglycerides (0.60 ± 0.40 vs. 0.89 ± 0.31 mmol·L-1 p = 0.012), and lower maximal oxygen power (44.43 ± 8.29 vs. 35.48 ± 8.72 mL·kg-1·min-1, p = 0.003), total physical activity counts (451.01 ± 133.52 vs. 346.87 ± 101.97 counts·min-1, p = 0.004), metabolic equivalents (METs) (2.41 ± 0.60 vs. 2.09 ± 0.41 METs, p = 0.033), moderate-to-vigorous intensity physical activity [MVPA: 89.57 (61.00-124.14) vs (53.19 (35.68-63.16) min, p = 0.001], and the percentage of time spent in MVPA [11.91 (7.74-16.22) vs 8.56 (6.18-10.12) %, p = 0.038]. The level of high-density lipoprotein cholesterol was positively associated with METs (ß = 0.29, p = 0.030, model R2 = 0.168), and the level of triglycerides was negatively associated with physical activity counts (ß = - 0.001, p = 0.018, model R2 = 0.205) and METs (ß = - 0.359, p = 0.015, model R2 = 0.208), and positively associated with time spent in sedentary behaviour (ß = 0.002, p = 0.041, model R2 = 0.156) in persons living with T1DM. CONCLUSIONS: Chinese youth with T1DM, despite their young age and short duration of diabetes, present early signs of CVD risk, as well as low physical activity levels and cardiorespiratory fitness compared to apparently healthy peers without diabetes. Regular physical activity is associated with a beneficial cardiovascular profile in T1DM, including improvements in lipid profile. Thus, physical activity participation should be widely promoted in youth living with T1DM.

The association between heart rate variability, reaction time, and indicators of workplace fatigue in wildland firefighters.

PURPOSE: To understand the association between heart rate variability and indices of fatigue, total sleep time, and reaction time in shift workers. METHODS: Ten participants from the British Columbia Wildfire Service management team were examined over a 14-day active fire-line period. Daily measures of subjective fatigue, sleepiness, and alertness were recorded using a visual analog scale. Daily total sleep time was recorded using a wrist actigraph. Cardiac autonomic modulation was examined each morning using heart rate variability (HRV). Three measures of reaction time (simple reaction time, choice reaction tie, and discriminatory reaction time) was examined on days 1, 5, 10, and 14. Multiple linear regression analysis was utilized to examine the association between HRV and indices of fatigue, total sleep time, and reaction time. RESULTS: Mean shift duration was 13.8 ± 0.77 h. Significant inverse associations were observed between HRV and sleepiness [r = - 0.60, p = 0.000] and fatigue [r = - 0.55, p = 0.000], and a positive association with total sleep time (min) [r = 0.28, p = 0.009]. There were no significant relationships between HRV and simple reaction time (ms) [r = - 0.32, p = 0.182], choice reaction time (ms) [r = - 0.10, p = 0.850], or discriminatory reaction time (ms) [r = - 0.09, p = 0.881]. CONCLUSIONS: HRV displayed significant associations with indices of fatigue and sleep, whereby demonstrating its utility as a practical tool for monitoring the development of fatigue in wildland firefighters and for providing insight when to make lifestyle modifications to preserve alertness.

Masters Athlete Screening Study (MASS): Insights Into the Psychological Impact of Cardiovascular Preparticipation Screening.

OBJECTIVE: To determine the psychological impact of a cardiovascular disease (CVD) diagnosis identified during preparticipation screening (PPS) of masters athletes. DESIGN: Cross-sectional study. SETTING: Masters athletes diagnosed with CVD through the Masters Athletes Screening Study. PARTICIPANTS: Sixty-seven athletes (89.6% male, mean age at diagnosis 60.1 ± 7.1 years, range 40-76) with diagnoses of coronary artery disease (CAD) (73.1%), high premature ventricular contraction burden (9.0%), mitral valve prolapse (7.5%), atrial fibrillation (AF) (3.0%), bicuspid aortic valve (3.0%), aortic dilatation (1.5%), coronary anomaly (1.5%), and rheumatic heart disease (1.5%). Three participants had multiple diagnoses. INTERVENTION: Online survey distributed to masters athletes identified with CVD. MAIN OUTCOME MEASURES: Assessment of psychological distress [Impact of Event Scale-Revised (IES-R)], perceptions of screening, and preferred support by CVD type. RESULTS: The median total IES-R and subscale scores were within the normal range {median [interquartile range (IQR)] total 2.0 [0-6.0]; intrusion 1.0 [0-3.0]; avoidance 0 [0-3.0]; hyperarousal 0 [0-1.0]}. Athletes with bicuspid aortic valve [20.5 (IQR, 4.0-37.0)], AF [7.0 (IQR, 0-14.0)], and severe CAD [5.5 (IQR, 1.0-12.0)] had the highest total IES-R scores. One individual with bicuspid aortic valve reported a significant stress reaction. Ten athletes (14.9%) had scores >12. Ninety-three percent of athletes were satisfied having undergone PPS. Preferred type of support varied by cardiovascular diagnosis. CONCLUSIONS: The majority of masters athletes diagnosed with CVD through PPS do not experience significant levels of psychological distress. Athletes diagnosed with more severe types of CVD should be monitored for psychological distress. Support should be provided through a multidisciplinary and individualized approach.

Predicting Family and Child Physical Activity across Six-Months of a Family-Based Intervention: An Application of Theory of Planned Behaviour, Planning and Habit.

Family-based physical activity (PA) interventions have proven effective in modifying PA; yet, the underlying mechanisms are currently unclear. In this study, we follow-up upon prior trial data that showed changes to child moderate-to-vigorous PA (MVPA) as a result of a family education+planning intervention compared to an education-only condition. We examined parents' perceived family PA frequency, family PA social cognitions, and family PA habit over 26 weeks between the two conditions. One hundred and two parents (of children aged 6 to 12 yrs), were recruited through advertisements and randomized to either the planning + education condition (n = 52) or an education-only condition (n = 50). Self-reported family PA, and measures of theory of planned behaviour, planning intention, and habit were completed by the contact parent at baseline, six-week, 13-week, and 26-week time-periods. The education+planning intervention increased planning intention (p <.01) and family PA (p =.06) compared to the© education-only group. The effect of condition on the putative mediators did not explain these changes (all 95% CIs crossed 0), and family PA was associated with child MVPA only at 13 weeks (p <.01). Intervention 20 assignment had a small indirect effect on family PA (favouring©the education+planning group) via Habit. Perceived behavioural©control and habit were consistent predictors of family PA (p <.05), but not PA intention or planning intention (p >.05). The planning+education intervention showed improved family PA and planning intention, yet null mediation results suggest that other variables from the family system (e.g., child motivation, other parent's motivation and plans) are likely needed to fully understand the intervention effects. The promotion of perceived behavioural control and habit to assist in family PA is recommended for future research in this population.

Exercise training affects hemodynamics not cardiac function during anthracycline-based chemotherapy.

INTRODUCTION: Preclinical data demonstrate the potential for exercise training to protect against anthracycline-related cardiotoxicity, but this remains to be shown in humans. PURPOSE: To assess whether exercise training during anthracycline-based chemotherapy for treatment of breast cancer affects resting cardiac function and hemodynamics. METHODS: In this prospective, non-randomized controlled study, 26 women who participated in aerobic and resistance training 3×/wk during chemotherapy were compared to 11 women receiving usual care. Two-dimensional echocardiography was performed before and 7-14 days after completion of anthracycline-based chemotherapy. Pre- and post-anthracycline cardiac function and hemodynamic variables were compared within each group with paired t-tests; the change was compared between groups using ANCOVA with adjustment for baseline values. RESULTS: Left ventricular longitudinal strain, volumes, ejection fraction, E/A ratio, and mass did not change in either group. Hemoglobin, hematocrit, and mean arterial pressure decreased significantly from baseline in both groups (all p < 0.05) with no differences between groups. Cardiac output increased in the usual care group only (+ 0.27 ± 0.24 L/min/m2, p < 0.01), which differed significantly from the exercise group (p = 0.03). Systemic vascular resistance (SVR) decreased in both groups (usual care: - 444, p < 0.01; exercise: - 265, dynes/s/cm5, p = 0.01). However, the reduction in SVR was significantly attenuated in the exercise group (p = 0.03) perhaps due to a compensatory decrease in estimated vessel lumen radius. CONCLUSION: Exercise training during anthracycline chemotherapy treatment had no effect on resting cardiac function but appeared to modify hemodynamic responses. Specifically, exercise training attenuated the drop in SVR in response to chemotherapy-related reductions in hematocrit potentially by increasing vessel lumen radius.

Parents and children active together: a randomized trial protocol examining motivational, regulatory, and habitual intervention approaches.

BACKGROUND: Regular physical activity (PA) is associated with many health benefits during childhood, and tracks into desirable PA patterns and health profiles in adulthood. Interventions designed to support these behaviours among young children are critical. Family-based interventions focusing on parent-child activities together (i.e., co-activity) among preschool-aged children are warranted. Targeting parental support practices can increase the frequency of co-activity, however interventions must move beyond merely building intention and planning skills for successful maintenance. Interventions designed to increase co-activity habit strength may facilitate the sustainability and thus impact child PA. The purpose of this study is to compare the effects of three intervention conditions designed to increase child PA through co-activity: a standard education condition (information about benefits), a planning (action planning, coping planning) + education condition and a habit (context-dependent repetition from prompts and cues) + planning +education condition. METHODS/DESIGN: A longitudinal three-arm parallel design randomized trial will compare three conditions over six months. Families are eligible if they have at least one child between 3y and 5y that is not meeting 60mins/day of moderate to vigorous physical activity (MVPA). The primary outcome (child MVPA) is assessed via accelerometry at baseline, six weeks, three months and six months (primary endpoint). Intervention materials targeting co-activity are delivered post baseline assessment, with booster sessions at six weeks and three months. Parental co-activity habit, parent-child co-activity and other behavioural constructs are also assessed via questionnaire at all measurement occasions. As tertiary outcomes, parental PA is measured via accelerometry and co-activity is measured via a Bluetooth-enabled proximity feature. A total of 106 families have been recruited thus far from the Greater Victoria region. The study is ongoing with a minimum target of 150 families and an anticipated recruitment completion date of August 2022. DISCUSSION: This protocol describes the implementation of a randomized trial evaluating the effectiveness of a habit formation group compared with a planning group and an education only group to increase child PA through targeting parent-child co-activity. This information could prove useful in informing public health initiatives to promote PA among families with preschool-aged children. TRIAL REGISTRATION: This trial was prospectively registered on clinicaltrials.gov in February 2016, identifier NCT03055871 .

Predicting personal physical activity of parents during participation in a family intervention targeting their children.

The purpose of this study was to examine the effect of two family interventions targeting inactive children on their parents' MVPA. Correlates of MVPA across the trial in the form of theory of planned behavior (TPB) and multi-process action control (M-PAC) were examined as exploratory outcomes. Parents (of children aged 6-12 years) were randomized to either a planning + education (n = 52) or an education only condition (n = 50) designed to improve child MVPA. Parental MVPA (accelerometry, self-report) was assessed at baseline, 6-week, 13-week, and 26-week time-periods. Parental MVPA increased from baseline to 26 weeks (p < .05), but there were no group differences. The TPB was unable to predict MVPA and application of M-PAC showed this was because nearly all participants possessed the intention to be active. Successful-compared to unsuccessful-intenders had stronger habit in four of the six tests employed (p < .05). Parent MVPA may benefit during a family-based intervention but the putative mediators of this increase are unclear.Registered trial clinicaltrials.gov #NCT01882192.

Fatigue and sleep patterns among Canadian wildland firefighters during a 17-day fire line deployment.

The purpose of this investigation was to enhance our understanding of the effects the current British Columbia Wildfire Service (BCWS) firefighting schedule have on the development of fatigue and sleep deprivation. This was a cohort study that objectively and subjectively measured sleep quantity, sleep quality, and fatigue throughout a 17-day British Columbia wildland firefighting deployment. Wildland firefighters (n = 30) conducted daily testing of sleep and fatigue measures during 14 days of activity on the fire line and three days immediately post deployment during their three-day rest period, for a total of 17 days of data collection. Sleep was assessed using wrist-worn actigraphy (ActiGraph LLC, Pensacola, FL) and subjective sleep questionnaires. Fatigue was assessed using subjective fatigue questionnaires and cognitive performance through the psychomotor vigilance test. Total sleep time was less on fire days (M = 6.6 h ± 49.2 min) compared to non-fire days (M = 6.8 h ± 92.2 min). Participants performed poorer on cognitive performance tests, (p = 0.288), and reported being significantly sleepier, (p = 0.038), toward the end of their 17-day deployment compared to day 1. Participants continued to report high levels of sleepiness, fatigue, and poor quality of sleep on their rest days compared to their fire line days. Working 14 consecutive days was associated with increased levels of objective fatigue and suboptimal sleep in wildland firefighters. Wildland firefighters reported significantly higher levels of fatigue and decreased alertness with increasing days on deployment and these levels did not improve following a three-day rest period.

Ethnic differences in the cardiac responses to aerobic exercise.

Background: Cardiovascular disease disproportionately affects North American Indigenous populations. Ethnic differences in cardiac responses to exercise are known, though Indigenous populations response is unknown. To evaluate cardiac responses to aerobic exercise among Canadian Indigenous and European adults. Methods: Indigenous (N = 12, 4 females, 1 male incomplete) and European (N = 12, all completed) Canadian age and sex-matched adults 19-40 years and free of cardiovascular disease or diabetes completed a cycle ergometer maximal aerobic power test and 30 min at 60% maximal aerobic capacity on two separate days. Echocardiographic assessments preceded and immediately followed exercise. Results: Responses to maximal exercise were similar among ethnicities including decreases in stroke volume index, cardiac output index and ejection fraction, and increases in arterial-ventricular coupling. However, following submaximal exercise, only Indigenous adults demonstrated reductions in end systolic volume, end diastolic volume (154.8 ± 40.6 mL to 136.5 ± 33.0 mL, p = 0.01, vs. 149.4 ± 22.4 mL to 147.1 ± 27.0 mL; p = 0.81), stroke volume index (44.9 ± 8.7 mL m-2 to 38.0 ± 6.5 mL m-2, p = 0.002, vs. 46.4 ± 7.1 mL m-2 to 44.0 ± 6.5 mL m-2; p = 0.28) and arterial compliance. Conclusion: Indigenous and European adults demonstrated similar cardiac responses to maximal exercise, though only Indigenous adults demonstrated cardiac responses to submaximal exercise.

Monitoring the Prescribed and Experienced Heart Rate-Derived Training Loads in Elite Field Hockey Players.

Perrotta, AS, Taunton, JE, Koehle, MS, White, MD, and Warburton, DER. Monitoring the prescribed and experienced heart rate-derived training loads in elite field hockey players. J Strength Cond Res 33(5): 1394-1399, 2019-This study examined the congruence between the prescribed and experienced heart rate-derived training loads over a 5-week periodized mesocycle. Twenty-four elite female field hockey players training as part of a national team were monitored before an (FIH) Hockey World League tournament. Three on-field training sessions per week were prospectively designed focusing on technical, tactical, and physiologically oriented hockey drills. A training load value, modeling the periodized weekly loading scheme, was prescribed for each training session and was calculated using normative training load responses from performing on-field hockey drills. Magnitude-based inferences focusing on the effect size (ES) and a Pearson correlation coefficient (r) were used to examine the degree of difference and the strength of correlation between the prescribed and experienced training loads. A significant correlation was observed between the experienced and prescribed training loads over the 5-week mesocycle (r = 0.92, 90% confidence limit [CL] [0.84-0.96]). The percentage difference and the ES between the achieved and prescribed training loads were as follows: week 1 demonstrated a 2.0% difference (ES = 0.10, 90% CL [-0.22-0.41]), week 2 a -5.4% difference (ES = -0.41, 90% CL [-0.75 to -0.07]), week 3 a -1.5% difference (ES = -0.09, 90% CL [-0.37 to 0.20]), week 4 a 7.1% difference (ES = 0.46, 90% CL [0.14-0.78]), and week 5 a 3.5% difference (ES = 0.18, 90% CL [-0.17 to 0.53]). This investigation demonstrates the efficacy for coaches to prospectively design on-field training sessions using normative training load data to enhance the congruence between the prescribed and experienced training loads over a periodized mesocycle.

Efficacy of Online Multi-Player Versus Single-Player Exergames on Adherence Behaviors Among Children: A Nonrandomized Control Trial.

Background: Exergames have the potential to significantly increase physical activity in children. Studies to date have shown mixed results and often rely on self-reported data. Multi-player gaming may augment participation. Purpose: The purpose of the study was to examine children's adherence behaviors in multi-player online exergames compared to a single-player condition within a home environment. Methods: Seventy-two children, aged 9-12 years, who were not meeting physical activity guidelines at baseline, were allocated to the multi-player or single-player condition. Six-week cycle-based exergaming trials took place 5 day/week in the early evening with online game supervision. Bike use was objectively recorded via game logs. Results: Adherence was high throughout the trial. Play session duration was M = 37.65 (SD = 15.39) min/day, and overall play duration was M = 133.45 (SD = 81.27) min in Week 1 and M = 77.23 (SD = 84.09) min in Week 6. Total physical activity was significantly higher at 6 weeks compared to baseline (p = .01, ηp2 = .13). There was no significant difference in play duration between conditions (p = .57, ηp2 = .01). Conclusion: This trial objectively demonstrated that exergames can promote high adherence levels. Multi-player capabilities did not augment adherence levels. Introducing new games throughout the trial may have motivated participants to keep playing, regardless of whether play was against real or artificial opponents. Weekly play duration decreased due to a significant drop in play frequency. For children who enjoy exergames, innovative solutions to promote more frequent exergame play are needed. Clinical This Registration: NCT02032667.

Efficacy of Hot Yoga as a Heat Stress Technique for Enhancing Plasma Volume and Cardiovascular Performance in Elite Female Field Hockey Players.

Perrotta, AS, White, MD, Koehle, MS, Taunton, JE, and Warburton, DER. Efficacy of hot yoga as a heat stress technique for enhancing plasma volume and cardiovascular performance in elite female field hockey players. J Strength Cond Res 32(10): 2878-2887, 2018-This investigation examined the efficacy of hot yoga as an alternative heat stress technique for enhancing plasma volume percentage (PV%) and cardiovascular performance. Ten international caliber female field hockey players completed six 60-minute hot yoga sessions using permissive dehydration over 6 days, followed by a 6-day national team camp. Changes in PV% were examined throughout the intervention and postintervention period. A graded maximal exercise test was performed in a thermoneutral environment (23.2 ± 1.0° C) 24 hours before and 24 hours after intervention. Six days of hot yoga initiated a moderate state of hypovolemia (PV% = -3.5%, 90% confidence limit [CL] [-6.9 to -0.13]), trivial improvements in maximal aerobic power (V[Combining Dot Above]O2max) (effect size [ES] = 0.06, 90% CL [-0.16 to 0.28]), and run time to exhaustion (ES = 0.11, 90% CL [-0.07 to 0.29]). Small meaningful improvements were observed in running speed (km·h) at ventilatory threshold (VT1) (ES = 0.34, 90% CL [-0.08 to 0.76]), VT2 (ES = 0.53, 90% CL [-0.05 to 1.1]), along with adaptations in the respiratory exchange ratio during high-intensity exercise (ES = -0.25, 90% CL [-0.62 to 0.12]). A large plasma volume expansion transpired 72 hours after intervention (PV% = 5.0%, 90% CL [1.3-8.7]) that contracted to a small expansion after 6 days (PV% = 1.6%, 90% CL [-1.0 to 4.2]). This investigation provides practitioners an alternative heat stress technique conducive for team sport, involving minimal exercise stress that can preserve maximal cardiovascular performance over periodized rest weeks within the yearly training plan. Furthermore, improvements in submaximal performance and a delayed hypervolemic response may provide a performance-enhancing effect when entering a 6-day competition period.

Health benefits of physical activity: a systematic review of current systematic reviews.

PURPOSE OF REVIEW: The health benefits of physical activity and exercise are clear; virtually everyone can benefit from becoming more physically active. Most international guidelines recommend a goal of 150 min/week of moderate-to-vigorous intensity physical activity. Many agencies have translated these recommendations to indicate that this volume of activity is the minimum required for health benefits. However, recent evidence has challenged this threshold-centered messaging as it may not be evidence-based and may create an unnecessary barrier to those who might benefit greatly from simply becoming more active. This systematic review evaluates recent systematic reviews that have examined the relationship between physical activity and health status. RECENT FINDINGS: Systematic reviews and/or meta-analyses (based largely on epidemiological studies consisting of large cohorts) have demonstrated a dose-response relationship between physical activity and premature mortality and the primary and secondary prevention of several chronic medical conditions. The relationships between physical activity and health outcomes are generally curvilinear such that marked health benefits are observed with relatively minor volumes of physical activity. SUMMARY: These findings challenge current threshold-based messaging related to physical activity and health. They emphasize that clinically relevant health benefits can be accrued by simply becoming more physically active. VIDEO ABSTRACT: http://links.lww.com/HCO/A42.

Heart-rate response to alpha2-adrenergic receptor antagonism by antipsychotics.

PURPOSE: To explore the relationship between antipsychotic-associated antagonism of alpha2-adrenergic receptors and resting heart rate in individuals with schizophrenia. METHODS: Thirty-one inpatients treated with antipsychotics were included in this exploratory analysis. Antipsychotic doses were converted to haloperidol equivalents for alpha2-adrenergic receptor antagonism. Resting heart rate was measured with the patient in the seated upright posture. RESULTS: After controlling for confounding variables, the relationship between alpha2-adrenergic receptor antagonism and resting heart rate demonstrated a positive linear effect (P = 0.002) as well as a nonlinear effect that accounted for an additional 14% of the variability in resting heart rate (P = 0.005). CONCLUSION: The observed inverted-U relationship between alpha2-adrenergic receptor antagonism and resting heart rate can possibly be attributed to an altered response of beta1-adrenergic receptors to increased norepinephrine release. Further investigations are required to confirm this exploratory finding, taking into account additional variables that include other receptors which either directly or indirectly influence heart rate. CLINICALTRIALS. GOV IDENTIFIER: NCT01392885.

Evaluation of a physical activity intervention for new parents: protocol paper for a randomized trial.

BACKGROUND: Identifying critical life transitions in people's physical activity behaviors may illuminate the most opportune intervention apertures for chronic disease prevention. A substantive evidence base now indicates that parenthood is one of these critical transition points for physical activity decline. This study will examine whether a brief theory-based intervention can prevent a decline in physical activity among new parents over 6 months following intervention. This study protocol represents the first dyad-based physical activity initiative in the parenthood literature involving both mothers and fathers; prior research has focused on only mothers or only fathers (albeit limited), and has shown only short-term changes in physical activity. This study will be investigating whether a theory-based physical activity intervention can maintain or improve moderate to vigorous intensity physical activity measured via accelerometry of new parents over a 6 month period following intervention compared to a control group. METHODS: This study is a 6-month longitudinal randomized controlled trial. Parents are measured at baseline (2 months postpartum) with two assessment points at 6 weeks (3.5 months postpartum) and 3 months (5 months postpartum) and a final follow-up assessment at 6 months (8 months postpartum). The content of the theory-based intervention was derived from the results of our prior longitudinal trial of new parents using an adapted theory of planned behavior framework to predict changes in physical activity. RESULTS: A total of 152 couples have been recruited to date. Sixteen couples dropped out after baseline and a total of 88 couples have completed their 6-month measures. DISCUSSION: If the intervention proves successful, couple-based physical activity promotion efforts among parents could be a promising avenue to pursue to help mitigate the declines of physical activity levels during parenthood. These findings could inform public health materials and practitioners. TRIAL REGISTRATION: This trial has been registered with the Clinical Trials Registry maintained by the National Library of Medicine at the National Institutes of Health on April 19, 2014. The registration ID is NCT02290808 .

Stationary cycling exergame use among inactive children in the family home: a randomized trial.

Exergames may be one way to increase child physical activity, but long term adherence has seen little research attention. The primary objective of this study was to evaluate the usage of an exergame bike in comparison to a stationary bike in front of a TV across 3-months within a family home environment among children aged 10-14 years old. Seventy-three inactive children were recruited through advertisements and randomized to either the exergame condition (n = 39) or the standard bike condition (n = 34). Weekly bike use was recorded in a log-book. Both groups declined in bike use over time (t = 3.921, p < .01). Although the exergame group reported higher use (t = 2.0045, p < .05), this was most prominent during the first week. Overall, these results do not support exergames as a standalone physical activity intervention, and suggest that short duration examinations of exergames may be misleading.