Heart rate variability to assess ventilatory thresholds in professional basketball players

Purpose: The aim of this study was to determine if heart rate variability(HRV) during incremental test could be used to estimate ventilatory threshold(VT) in professional basketball players, with sufficient precision to be used in their training. Furthermore, the second aim was to analyse the association between HRV and 3 methods of VT determination by gas analysis.Methods: Twenty-four professional basketball players(age: 23.4 ± 4.9 years; height: 195.4 ± 9.8 cm; body mass: 92.2 ± 11.9 kg) performed an incremental running test to exhaustion. First ventilatory threshold(VT1) was determined by ventilatory equivalent(VE) and HRV and second ventilatory threshold(VT2) was determined by 3 methods of gases analysis(V-slope, VE and gas exchange ratio(R), and HRV). Pearson's coefficient(r) was used to detect differences between data and the strength of each relationship. The mean of absolute differences and Bland–Altman analysis were used to evaluate whether there was agreement.Results: The results showed no significant differences in HR and oxygen consumption(VO2) at VT1 between the 2 methods. Furthermore, no significant differences among the methods of gases analysis and HRV were observed in speed, HR, and VO2 at VT2. Moreover, VTs estimated using HRV and gas methods were significantly correlated. Correlation in HR values was higher between R and HRV(r = 0.96) and VE and HRV(r = 0.96) than V-slope and HRV(r = 0.90).Conclusion: These findings provide a practical, inexpensive approach for evaluating specific training loads when determining VT2 in basketball players. Therefore, HRV is an alternative method to determine VT2 without the application of expensive technology that limits its use to laboratories.

Non-exhaustive double effort test is reliable and estimates the firs ventilatory threshold intensity in running exercise

Purpose: The present study aimed to investigate the reliability of the non-exhaustive double effort(NEDE) test in running exercise and its associations with the ventilatory thresholds(VT_1 and VT_2) and the maximal lactate steady state(MLSS).Methods: Ten healthy male adults(age: 23 ± 4 years, height: 176.6 ± 6.4 cm, body mass: 76.6 ± 10.7 kg) performed 4 procedures:(1) a ramp test for VT_1 and VT_2 determinations measured by ratio of expired ventilation to O_2 uptake(VE/VO_2) and expired ventilation to CO_2 output(VE/VCO_2) equivalents, respectively;(2) the NEDE test measured by blood lactate concentration(NEDE_(LAC)) and heart rate responses(NEDE_(HR));(3) a retest of NEDE for reliability analysis; and(4) continuous efforts to determine the MLSS intensity. The NEDE test consisted of4 sessions at different running intensities. Each session was characterized by double efforts at the same running velocity(E1 and E2, 180 s), separated by a passive recovery period(90 s rest). LAC and HR values after E1 and E2(in 4 sessions) were used to estimate the intensity equivalent to"null delta" by linear fit. This parameter represents, theoretically, the intensity equivalent to maximal aerobic capacity.Results: The intraclass correlation coefficient indicated significant reliability for NEDE_(LAC)(0.93) and NEDE_(HR)(0.79)(both p < 0.05). There were significant correlations, no differences, and strong agreement with the intensities predicted by NEDE_(LAC)(10.1 ± 1.9 km/h) and NEDE_(HR)(9.8 ± 2.0 km/h) to VT_1(10.2 ± 1.1 km/h). In addition, despite significantly lower MLSS intensity(12.2 ± 1.2 km/h), NEDE_(LAC) and NEDE_(HR) intensities were highly correlated with this parameter(0.90 and 0.88, respectively).Conclusion: The NEDE test applied to running exercise is reliable and estimates the VT_1 intensity. Additionally, NEDE intensities were lower but still correlated with VT_2 and MLSS.

What is the most effective exercise protocol to improve cardiovascular fitness in overweight and obese subjects？

Background: Increased peak oxygen consumption(VO2 peak) can reduce cardiovascular risks associated with obesity. Our aim was to analyze the effect of a weight loss program on cardiovascular fitness in overweight(W) and obese(O) subjects.Methods: One hundred and sixty-seven subjects(77 males and 90 females), aged 18–50 years, performed a modified Bruce protocol before(pre)and after(post) a weight loss program of 24 weeks. This program combined physical training(strength, S; endurance, E; combined strength + endurance, SE; or physical activity recommendation, PA) 3 times per week, with a 25%–30% caloric restriction diet.Results: VO2 peak improved in overweight and obese males(pre and post values in L/min, respectively; W = 3.2 ± 0.6 vs. 3.7 ± 0.5, p < 0.001;O = 3.6 ± 0.6 vs. 3.8 ± 0.6, p = 0.013) as well as in overweight females(2.0 ± 0.3 vs. 2.3 ± 0.4, p < 0.001). VO2 peak in the first ventilatory threshold(VT1) increased for all 4 interventions in males(p < 0.05), except for S in the obese group(1.6 ± 0.2 vs. 1.7 ± 0.3, p = 0.141). In females, it increased in E(0.9 ± 0.2 vs. 1.4 ± 0.3, p < 0.001), SE(0.9 ± 0.2 vs. 1.2 ± 0.4, p = 0.003), and PA(0.9 ± 0.1 vs. 1.2 ± 0.2, p = 0.006) in overweight groups. Time-to-exhaustion improved in all subjects except for females in PA group(15.7 ± 0.3 min vs. 15.9 ± 0.3 min, p = 0.495).Conclusion: Our results suggest that all methods, including the recommendation of physical activity, can improve cardiovascular fitness in overweight subjects and obese males.