Effects of Pre-Term Birth on the Cardio-Respiratory Responses to Hypoxic Exercise in Children

Pre-term birth is associated with numerous cardio-respiratory sequelae in children. Whether these impairments impact the responses to exercise in normoxia or hypoxia remains to be established. Fourteen prematurely-born (PREM) (Mean ± SD; gestational age 29 ± 2 weeks; age 9.5 ± 0.3 years), and 15 full-term children (CONT) (gestational age 39 ± 1 weeks; age 9.7 ± 0.9 years), underwent incremental exercise tests to exhaustion in normoxia (FiO2 = 20.9%) and normobaric hypoxia (FiO2 = 13.2%) on a cycle ergometer. Cardio-respiratory variables were measured throughout. Peak power output was higher in normoxia than hypoxia (103 ± 17 vs. 77 ± 18 W; p < 0.001), with no difference between CONT and PREM (94 ± 23 vs. 86 ± 19 W; p = 0.154). V̇O2peak was higher in normoxia than hypoxia in CONT (50.8 ± 7.2 vs. 43.8 ± 9.9 mL·kg−1·min−1; p < 0.001) but not in PREM (48.1 ± 7.5 vs. 45.0 ± 6.8 mL·kg−1·min−1; p = 0.137; interaction p = 0.044). Higher peak heart rate (187 ± 11 vs. 180 ± 10 bpm; p = 0.005) and lower stroke volume (72 ± 13 vs. 77 ± 14 mL; p = 0.004) were observed in normoxia versus hypoxia in CONT, with no such differences in PREM (p = 0.218 and > 0.999, respectively). In conclusion, premature birth does not appear to exacerbate the negative effect of hypoxia on exercise capacity in children. Further research is warranted to identify whether prematurity elicits a protective effect, and to clarify the potential underlying mechanisms.

Predictive equations to estimate peak aerobic capacity and peak heart rate in persons with Down syndrome

Estimations based on the available equations for predicting oxygen uptake (VO2) from treadmill speed of locomotion are not appropriate for individuals with Down syndrome (DS). We aimed at developing prediction models for peak absolute oxygen uptake (VO2peak) and peak heart rate (HRpeak) based on retrospective data from a healthy population with and without Down syndrome (DS). A cross-sectional analysis of VO2peak and HRpeak was conducted in 196 and 187 persons with and without DS, respectively, aged from 16-45 years. Non-exercise data alone versus combined with HRpeak were used to develop equations predictive of absolute VO2peak. Prediction equations for HRpeak were also developed. Two additional samples of participants (30 with, 29 without DS) enabled model cross-validation. Relative VO2peak and HRpeak were lowest for persons with DS across all ages (~ 40% and 20 bpm, respectively). For persons with DS, VO2peak predictions provided no differences compared with actual values. Predicted HRpeak was similar to actual values in both groups of participants. Large limits of agreement were obtained for VO2peak (DS: 735, non-DS: 558.2 mL.min-1) and HRpeak (DS: 24.8, non-DS: 16.6 bpm). Persons with DS exhibit low levels of VO2peak and HRpeak in all age groups included in this study. It is possible to estimate absolute VO2peak in persons with DS using non-exercise variables. HRpeak can be accurately estimated in groups of people with and without DS. Yet, because of large limits of agreement, caution is advised if using these equations for individual estimations of VO2peak or HRpeak in either population.

Intermittent face cooling reduces perceived exertion during exercise in a hot environment

Background Facial cooling (FC) is effective in improving endurance exercise performance in hot environments. In this study, we evaluated the impact of intermittent short-lasting FC on the ratings of perceived exertion (RPE) during exercise. Methods Ten healthy men performed 40 continuous minutes of ergometric cycle exercise at 65% of the peak heart rate in a climatic chamber controlled at an ambient temperature of 35 °C and a relative humidity of 50%. In the control (CONT) trial, the participants performed the exercise without FC. In two cooling trials, each participant underwent 10 s of FC at 2- (FC2) and 4-min (FC4) intervals while continuing to exercise. FC was achieved by applying two soft-gel packs (cooled to 0 °C) directly and bilaterally on the forehead, eyes, and cheeks. In another cooling trial, 10 s of FC was performed at 2-min intervals using two soft-gel packs cooled to 20 °C (FC2-20). Results The RPE values in the FC4 trial were significantly lower than those in the CONT trial at 20 min (FC4, 11.6 ± 2.2 points; CONT, 14.2 ± 1.3 points; P < 0.01). Further, significant differences in the RPE values were observed between the FC4 and CONT trials at 5–15 min and 25–40 min (P < 0.05). RPE values were also significantly lower in the FC2 trial than in the CONT trial (5–40 min). Although the RPE values in the FC2-20 trial were significantly lower (5–10 min; 15–20 min) than those in the CONT trial, there were no significant differences in the RPE between the FC2-20 and CONT trials at 25–40 min. At 35 min, the RPE values were significantly higher in the FC2-20 trial than in the FC2 trial (P < 0.05). Conclusion Intermittent short-lasting FC was associated with a decrease in RPE, with shorter intervals and lower temperatures eliciting greater attenuation of increase in the RPE.

Sympathetic Neural Mechanisms Underlying Attended and Unattended Blood Pressure Measurement

Whether blood pressure (BP) values differ when BP is measured with or without the presence of a doctor (attended and unattended BP measurements) is controversial, and no information exists on whether and to what extent neurogenic mechanisms participate at the possible BP differences between these measurements. In this study, we assessed continuous beat-to-beat finger systolic BP and diastolic BP, heart rate, muscle, and skin sympathetic nerve traffic (microneurography) before and during BP measurement by an automatic device in the presence or absence of a doctor. This was done in 18 untreated mild-to-moderate essential hypertensive patients (age, 40.2±2.8 years, mean±SEM). During attended BP measurement, there was an increase in systolic BP, diastolic BP, heart rate, and skin sympathetic nerve traffic and a muscle sympathetic nerve traffic decrease, the peak changes being +5.3%,+8.4%,+9.4%,+30.9%, and −15.2%, respectively ( P <0.05 for all). In contrast, during unattended BP measurement, systolic BP, diastolic BP, heart rate, and skin sympathetic nerve traffic were modestly, albeit in most instances significantly, reduced, whereas muscle sympathetic nerve traffic remained almost unchanged. During unattended BP measurement, peak systolic BP was 14.1 mm Hg lower, peak heart rate was 10.6 bpm lower, and peak skin sympathetic nerve traffic was 8.5 bursts/min lower than the peak values detected during attended BP measurement. Thus the cardiovascular and neural sympathetic responses to the alerting reaction elicited by BP measurement in the presence of a doctor are almost absent during unattended BP measurement, during which, if anything, a modest cardiovascular sympathoinhibition occurs. This has important implications for comparison of studies using these different BP measurement approaches as well as for decision concerning threshold and target BP values for treatment.

Effectiveness of a physiotherapy and nutrition program in patients with coronary artery disease: randomized controlled trial

Funding Acknowledgements Type of funding sources: None. Introduction. Dietary and exercise interventions are effective strategies for improving physical and nutritional status of patients with coronary artery disease (CAD). However, few studies have applied a combined exercise protocol based on high intensity interval training (HIIT) and dietary education in patients with CAD with percutaneous coronary intervention (PCI). Purpose This study researches the effectiveness of a multidisciplinary program based in HIIT with dietary education (DEHIIT) in comparison with only HIIT, on adherence to Mediterranean diet in CAD patients with PCI. Methods. A prospective, assessor-blinded, parallel group, randomized trial was developed. The study was developed at a University research lab. Forty-four adults diagnosed with CAD (between 40 and 72 years), were randomized to receive either combined dietary intervention and HIIT (DEHIIT, n = 22) or only HIIT (HIIT, n = 22). The adherence to the Mediterranean diet was assessed with a 14-item tool of adherence to the Mediterranean diet (MEDAS-14) at baseline and after the intervention. DEHIIT performed a 3-month dietary intervention program combined with 24 HIIT sessions at 85-95% of peak heart rate, whilst HIIT performed a 3-month HIIT sessions at 85-95% of peak heart rate. This study did not receive any funding. No conflict of interest is declared. Results. After three months, regarding to MEDAS-14, DEHIIT increased the fish/seafood consumption significantly (p = 0.001) and decreased the fruit consumption (p = 0.032) and dry fruits (p = 0.006). And, when comparing between groups, DEHIIT obtained significantly more MEDAS-14 score (p = 0.01) and more adherence to dieta mediterránea (p = 0.001). No adverse events were reported. Conclusions. A combined protocol including dietary intervention and HIIT can bring benefits for CAD patients with PCI on adherence to Mediterranean diet in comparison to only HIIT. Consequently, our combined program could be used as a treatment option in the therapeutic approach for these patients.

Multidisciplinary program based in physiotherapy and nutrition in coronary artery disease patients: randomized controlled trial

Funding Acknowledgements Type of funding sources: None. Introduction. The interventions on eating habits and exercise in physiotherapy programs are usually recommended in coronary artery disease (CAD), since they are beneficial to improve physical and nutritional status of patient. Despite this, scarce studies are focused on combined protocols based on high intensity interval training (HIIT) and dietary education in CAD patients with percutaneous coronary intervention (PCI). Purpose The main goal of this study was to compare the effectiveness of a multidisciplinary program based in HIIT, with a program based in dietary education and HIIT (DEHIIT), on eating habits in CAD patients with PCI. Methods. A prospective, randomized controlled trial with blinded outcome assessment was developed. The study was developed at a University research laboratory. 44 participants diagnosed with CAD, aged between 40 and 72 years, were randomly allocated to two treatment groups: HIIT group (HIITG, n = 22) and dietary intervention and HIIT group (DEHIITG, n = 22). The assessment consisted of applying a Food Frequency Questionnaires (FFQ) at baseline and post-intervention. DEHIITG performed a 3-month dietary intervention program combined with 24 HIIT sessions at 85-95% of peak heart rate, whilst HIITG performed a 3-month HIIT sessions at 85-95% of peak heart rate. This study did not receive any funding. No conflict of interest is declared. Results. At the end of the program, when comparing between groups, statistically significant changes were noted. DEHIITG consumed more olive oil (p = 0.021), chicken or turkey (p = 0.039), stir-fried with vegetables (p = 0.033), vegetables (p = 0.003), fish and seafood (p = 0.039), and quantity of commercial juices (p = 0.042), sweets and snacks (p = 0.033). HIITG showed more improvements than DEHIITG in soups and creams consumption (p = 0.042). No adverse events were reported. Conclusions. A dietary intervention with HIIT protocol yields better benefits than only HIIT on eating habits in CAD patients with PCI. Thus, our combined program could be considered a suitable treatment option among these patients.

Influence of players’ physical performances on the variation of the external and internal responses to repeated bouts of small-sided games across youth age categories

The aim of this study was twofold: (1) to test for differences on the external and internal responses encountered by youth soccer players during four bouts of 5-a-side small-sided game (SSG) across age categories and, (2) to analyze the external and internal responses attending to players’ sprinting and jumping profile within each age-category (i.e. under 14 (U14), under 16 (U16) and under 18 (U18)). Forty-eight young soccer players participated in this study and were distributed by each age-category. Players were classified based on jumping-profile (stronger and weaker) and sprint-profile (faster and slower). Also, players played four bouts of 4 min of a 5-a-side SSG, including goalkeepers. Likewise, external responses (i.e. total distance, distance covered at walking, jogging and high-intensity speeds, number of accelerations and decelerations, body impacts and player load) and internal responses (peak heart rate, % of peak heart rate and training impulse) were collected. The main results revealed a significant age-category by bout interaction for total distance covered, distance at jogging, number of accelerations, body impacts and player load for players from the U16 and U18 age categories, showing lower values during the last bouts, compared to the first bouts ( p ≤ 0.001–0.020, [Formula: see text] = 0.13–0.17). Moreover, while no significant ( p = 0.09–0.95) sprint-profile by bout interaction was found for the registered variables across age categories, stronger U18 players showed a smaller decrease across bouts for distance covered at high-intensity, compared to weaker U18 players. These findings suggest there is a need for coaching staff to include training strategies that allow for reducing accumulated neuromuscular fatigue in U16 and U18 age categories.

395 Exercise Capacity is Maintained in Older Military Personnel with Moderate to Severe Obstructive Sleep Apnea

Introduction The relationship between moderate to severe OSA and exercise capacity remains unclear. Prior studies showing a reduction in VO2 max in this population have mostly involved middle-aged and overweight patients. We looked to determine if this trend in VO2 max was present in a similarly aged population of military personnel with previously undiagnosed moderate to severe OSA. Methods We studied 170 middle-aged male military members who underwent cardiopulmonary exercise testing (CPET) and polysomnography (PSG) as a part of a comprehensive evaluation for an established military program. For analysis, patients were categorized either into an OSA group (apnea-hypopnea index (AHI) ≥ 15 events/h) or control group (AHI &lt; 15 events/h). VO2 max was compared between groups. Results Mean AHI was 29.0 in the OSA group (n =58) versus 7.4 in the controls (n = 112). Patients were of similar age (53.1 vs. 53.7 years) and BMI was slightly higher in the OSA group (27.5kg/m2 versus 26.3 kg/m2, P = .0077). Percent-predicted VO2 max was supernormal in both groups, though was comparatively lower in the OSA group (117% vs. 125%; P &lt;.001). There was a trend toward a blunted heart rate response to exercise in the OSA group as represented by peak heart rate (163 vs. 178; p=0.07). Conclusion Older military personnel with moderate to severe OSA have normal exercise capacity. This may suggest that the low-arousal OSA phenotype often noted in military personnel does not significantly influence exercise capacity or that regular exercise helps limit its impact. It remains likely that the effect of untreated OSA on exercise capacity is influenced by several variables including age, BMI, OSA phenotype, and regularity of exercise. Trends in VO2 max and peak heart rate noted in this study may suggest that untreated OSA in certain populations can negatively impact exercise capacity Support (if any) No external funding

Aerobic exercise capacity is maintained over a 5-year period in mild-to-moderate chronic kidney disease: a longitudinal study

Background Aerobic exercise capacity is reduced in non-dialysis chronic kidney disease (CKD), but the magnitude of changes in exercise capacity over time is less known. Our main hypothesis was that aerobic ExCap would decline over 5 years in individuals with mild-to-moderate CKD along with a decline in renal function. A secondary hypothesis was that such a decline in ExCap would be associated with a decline in muscle strength, cardiovascular function and physical activity. Methods We performed a 5-year-prospective study on individuals with mild-to-moderate CKD, who were closely monitored at a nephrology clinic. Fiftytwo individuals with CKD stage 2–3 and 54 age- and sex-matched healthy controls were included. Peak workload was assessed through a maximal cycle exercise test. Muscle strength and lean body mass, cardiac function, vascular stiffness, self-reported physical activity level, renal function and haemoglobin level were evaluated. Tests were repeated after 5 years. Statistical analysis of longitudinal data was performed using linear mixed models. Results Exercise capacity did not change significantly over time in either the CKD group or controls, although the absolute workloads were significantly lower in the CKD group. Only in a CKD subgroup reporting low physical activity at baseline, exercise capacity declined. Renal function decreased in both groups, with a larger decline in CKD (p = 0.05 between groups). Peak heart rate, haemoglobin level, handgrip strength, lean body mass and cardiovascular function did not decrease significantly over time in CKD individuals. Conclusions On a group level, aerobic exercise capacity and peak heart rate were maintained over 5 years in patients with well-controlled mild-to-moderate CKD, despite a slight reduction in glomerular filtration rate. In line with the maintained exercise capacity, cardiovascular and muscular function were also preserved. In individuals with mild-to-moderate CKD, physical activity level at baseline seems to have a predictive value for exercise capacity at follow-up.