Impaired Heat Adaptation From Combined Heat Training and “Live High, Train Low” Hypoxia

Purpose: To determine whether combining training in heat with “Live High, Train Low” hypoxia (LHTL) further improves thermoregulatory and cardiovascular responses to a heat-tolerance test compared with independent heat training. Methods: A total of 25 trained runners (peak oxygen uptake = 64.1 [8.0] mL·min−1·kg−1) completed 3-wk training in 1 of 3 conditions: (1) heat training combined with “LHTL” hypoxia (H+H; FiO2 = 14.4% [3000 m], 13 h·d−1; train at <600 m, 33°C, 55% relative humidity [RH]), (2) heat training (HOT; live and train <600 m, 33°C, 55% RH), and (3) temperate training (CONT; live and train <600 m, 13°C, 55% RH). Heat adaptations were determined from a 45-min heat-response test (33°C, 55% RH, 65% velocity corresponding to the peak oxygen uptake) at baseline and immediately and 1 and 3 wk postexposure (baseline, post, 1 wkP, and 3 wkP, respectively). Core temperature, heart rate, sweat rate, sodium concentration, plasma volume, and perceptual responses were analyzed using magnitude-based inferences. Results: Submaximal heart rate (effect size [ES] = −0.60 [−0.89; −0.32]) and core temperature (ES = −0.55 [−0.99; −0.10]) were reduced in HOT until 1 wkP. Sweat rate (ES = 0.36 [0.12; 0.59]) and sweat sodium concentration (ES = −0.82 [−1.48; −0.16]) were, respectively, increased and decreased until 3 wkP in HOT. Submaximal heart rate (ES = −0.38 [−0.85; 0.08]) was likely reduced in H+H at 3 wkP, whereas CONT had unclear physiological changes. Perceived exertion and thermal sensation were reduced across all groups. Conclusions: Despite greater physiological stress from combined heat training and “LHTL” hypoxia, thermoregulatory adaptations are limited in comparison with independent heat training. The combined stimuli provide no additional physiological benefit during exercise in hot environments.

The Influence of Changes in Acute Training Load on Daily Sensitivity of Morning-Measured Fatigue Variables in Elite Soccer Players

Purpose:To determine the sensitivity of a range of potential fatigue measures to daily training load accumulated over the previous 2, 3, and 4 d during a short in-season competitive period in elite senior soccer players (N = 10).Methods:Total highspeed-running distance, perceived ratings of wellness (fatigue, muscle soreness, sleep quality), countermovement-jump height (CMJ), submaximal heart rate (HRex), postexercise heart-rate recovery (HRR), and heart-rate variability (HRV: Ln rMSSD) were analyzed during an in-season competitive period (17 d). General linear models were used to evaluate the influence of 2-, 3-, and 4-d total high-speed-running-distance accumulation on fatigue measures.Results:Fluctuations in perceived ratings of fatigue were correlated with fluctuations in total high-speed-running-distance accumulation covered on the previous 2 d (r = –.31; small), 3 d (r = –.42; moderate), and 4 d (r = –.28; small) (P < .05). Changes in HRex (r = .28; small; P = .02) were correlated with changes in 4-d total high-speed-running-distance accumulation only. Correlations between variability in muscle soreness, sleep quality, CMJ, HRR%, and HRV and total high-speed-running distance were negligible and not statistically significant for all accumulation training loads.Conclusions:Perceived ratings of fatigue and HRex were sensitive to fluctuations in acute total high-speed-running-distance accumulation, although sensitivity was not systematically influenced by the number of previous days over which the training load was accumulated. The present findings indicate that the sensitivity of morning-measured fatigue variables to changes in training load is generally not improved when compared with training loads beyond the previous day’s training.

The examination of the heart rate regulation in healthy people with the stochastic tests methods

Background: The determination of relations between the complexity of the cardiovascular system regulation and the com-plexity of the test signal is not a fully solved problem. The elimination of this uncertainty can be done using stochastic test signals and power value which changes are random.Aim of research: To compare the reaction of cardio - vascular system during the deterministic and random loads.Material and methods:In the research,h two types of physical loads were used: the traditional bicycle ergometer test with stepwise increasing load and 3 minutes steps duration and test with a stochastic pseudonormal load values distribution and 30 seconds steps duration. Results: It is established that the average load required to achieve a submaximal heart rate was 509 W for the traditional and 445 W for the stochastic test, respectively. The time of obtained submaximal heart rate during stepwise-increasing load was 7 min., whereas during the stochastic load significantly less - 5min. The results show that the limit of efficiency of the cardio-vascular system during stochastic load test is achieved faster than during deterministic load test.Conclusions: Stress tests using random loads can be useful for the athletes training. Supposedly, the use of stochastic loads must be effective during rehabilitation of patients with cardiovascular diseases, for instance the increasing of the physical load time in each stage can be used in order to reach steady state. Also, the proposed study confirms the perspectives of non-linear and stochastic methods in the diagnosis of the cardiovascular system diseases.

Estimation of functional state in patients with hypertension with various disease duration

The object: to estimate functional condition of men with arterial hypertension of various disease length using veloergometry. Materials and methods. 86 men with arterial hypertension of 1 degree of various duration were examined: 60 men with the disease length 1,5 ± 0,2 year and 26 men with the disease length 8,0 ± 1,6 year, and 25 apparently healthy men were included. The standardized veloergometry was performed in all subjects using step-by-step increasing technique till either submaximal heart rate or limiting criteria were achieved. Results. Patients with long duration of arterial hypertension show reduced physical exertion tolerance, greater increase of systolic arterial pressure at small, average and high exertion power as compared to patients with short anamnesis of hypertension. They also have greater oxygen consumption by myocardium and its greater increment at average exertion power if compared to the rest level. The veloergometry test was discontinued due to the top level of systolic blood pressure, which occurred more often in this group.