Repeated Short-Term Bouts of Hyperoxia Improve Aerobic Performance in Acute Hypoxia.

ABSTRACT: Faulhaber, M, Schneider, S, Rausch, LK, Dünnwald, T, Menz, V, Gatterer, H, Kennedy, MD, and Schobersberger, W. Repeated short-term bouts of hyperoxia improve aerobic performance in acute hypoxia. J Strength Cond Res 37(10): 2016-2022, 2023-This study aimed to test the effects of repeated short-term bouts of hyperoxia on maximal 5-minute cycling performance under acute hypoxic conditions (3,200 m). Seventeen healthy and recreationally trained individuals (7 women and 10 men) participated in this randomized placebo-controlled cross-over trial. The procedures included a maximal cycle ergometer test and 3 maximal 5-minute cycling time trials (TTs). TT1 took place in normoxia and served for habituation and reference. TT2 and TT3 were conducted in normobaric hypoxia (15.0% inspiratory fraction of oxygen). During TT2 and TT3, the subjects were breathing through a face mask during five 15-second periods. The face mask was connected through a nonrebreathing T valve to a 300-L bag filled with 100% oxygen (intermittent hyperoxia) or ambient hypoxic air (placebo). The main outcome was the mean power output during the TT. Statistical significance level was set at p < 0.05. The mean power output was higher in the intermittent hyperoxia compared with the placebo condition (255.5 ± 49.6 W vs. 247.4 ± 48.2 W, p = 0.001). Blood lactate concentration and ratings of perceived exertion were significantly lower by about 9.7 and 7.3%, respectively, in the intermittent hyperoxia compared with the placebo condition, whereas heart rate values were unchanged. IH application increased arterial oxygen saturation (82.9 ± 2.6% to 92.4 ± 3.3%, p < 0.001). Repeated 15-second bouts of hyperoxia, applied during high-intensity exercise in hypoxia, are sufficient to increase power output. Future studies should focus on potential dose-response effects and the involved mechanisms.

Effects of Regular Long-Term Circuit Training (Once per Week) on Cardiorespiratory Fitness in Previously Sedentary Adults.

The purpose of the study was (1) to investigate the effects of regular long-term circuit training (once per week) on cardiorespiratory fitness (CRF) in sedentary adults and (2) to compare training progress with the effects of continued exercise participation by regularly active age-matched individuals. Ten sedentary, middle-aged (51 ± 6 years) individuals (sedentary group, SG) of both sexes performed 32 weeks (1 training session/week) of supervised circuit training and 10 weeks of self-managed training. Effects were compared to an age-matched group (51 ± 8 years; n = 10) of regularly active individuals (active group, AG). CRF (expressed as peak oxygen uptake: VO2peak; peak power output: PPO) and systemic blood pressure (BP) during the incremental test were measured at the start and after the training intervention. CRF decreased significantly within the AG (VO2peak: 43.1 ± 7.3 vs. 40.3 ± 6.5 mL/min/kg, p < 0.05; PPO: 3.3 ± 0.6 vs. 3.1 ± 0.6; p < 0.05) but was maintained in the SG. In addition, significant improvements in restoration of the oxygen level in leg muscles after exercise and reduced systolic BP (180 ± 14 vs. 170 ± 17 mmHg, p = 0.01) at submaximal exercise were found within the SG. However, differences in changes from pre to post did not reach significance between groups. In contrast to the regularly active individuals, circuit training once per week over 32 weeks prevented the aging-related decline of CRF in previously sedentary subjects and reduced systolic BP during submaximal exercise, indicating improved exercise tolerance.

Assessment of Maximal Aerobic Capacity in Ski Mountaineering: A Laboratory-Based Study.

This study aims to evaluate the agreement in maximum oxygen consumption (V˙O2max) between a running protocol and a ski mountaineering (SKIMO) protocol. Eighteen (eleven males, seven females) ski mountaineers (age: 25 ± 3 years) participated in the study. V˙O2max, maximum heart rate (HRmax), and maximum blood lactate concentration (BLAmax) were determined in an incremental uphill running test and an incremental SKIMO-equipment-specific test. V˙O2max did not differ between the SKIMO and uphill running protocols (p = 0.927; mean difference -0.07 ± 3.3 mL/min/kg), nor did HRmax (p = 0.587, mean difference -0.7 ± 5.1 bpm). A significant correlation was found between V˙O2max SKIMO and V˙O2max running (p ≤ 0.001; ICC = 0.862 (95% CI: 0.670-0.946)). The coefficient of variation was 4.4% (95% CI: 3.3-6.5). BLAmax was significantly lower for SKIMO compared to running (12.0 ± 14.1%; p = 0.002). This study demonstrates that V˙O2max determined with a traditional uphill running protocol demonstrates good agreement with an equipment-specific SKIMO protocol.

Effects of Acute Hypoxia on Lactate Thresholds and High-Intensity Endurance Performance-A Pilot Study.

The present project compared acute hypoxia-induced changes in lactate thresholds (methods according to Mader, Dickhuth and Cheng) with changes in high-intensity endurance performance. Six healthy and well-trained volunteers conducted graded cycle ergometer tests in normoxia and in acute normobaric hypoxia (simulated altitude 3000 m) to determine power output at three lactate thresholds (PMader, PDickhuth, PCheng). Subsequently, participants performed two maximal 30-min cycling time trials in normoxia (test 1 for habituation) and one in normobaric hypoxia to determine mean power output (Pmean). PMader, PDickhuth and PCheng decreased significantly from normoxia to hypoxia by 18.9 ± 9.6%, 18.4 ± 7.3%, and 11.5 ± 6.0%, whereas Pmean decreased by only 8.3 ± 1.6%. Correlation analyses revealed strong and significant correlations between Pmean and PMader (r = 0.935), PDickhuth (r = 0.931) and PCheng (r = 0.977) in normoxia and partly weaker significant correlations between Pmean and PMader (r = 0.941), PDickhuth (r = 0.869) and PCheng (r = 0.887) in hypoxia. PMader and PCheng did not significantly differ from Pmean (p = 0.867 and p = 0.784) in normoxia, whereas this was only the case for PCheng (p = 0.284) in hypoxia. Although investigated in a small and select sample, the results suggest a cautious application of lactate thresholds for exercise intensity prescription in hypoxia.

Acute Moderate Hypoxia Reduces One-Legged Cycling Performance Despite Compensatory Increase in Peak Cardiac Output: A Pilot Study.

In severe hypoxia, single-leg peak oxygen uptake (VO2peak) is reduced mainly due to the inability to increase cardiac output (CO). Whether moderate altitude allows CO to increase during single-leg cycling, thereby restoring VO2peak, has not been extensively investigated. Five healthy subjects performed an incremental, maximal, two-legged cycle ergometer test, and on separate days a maximal incremental one-leg cycling test in normoxia and in moderate hypoxia (fraction of inspired oxygen (FiO2) = 15%). Oxygen uptake, heart rate, blood pressure responses, power output, and CO (PhysioFlow) were measured during all tests. Moderate hypoxia lowered single-leg peak power output (154 ± 31 vs. 128 ± 26 watts, p = 0.03) and oxygen uptake (VO2) (36.8 ± 6.6 vs. 33.9 ± 6.9 mL/min/kg, p = 0.04), despite higher peak CO (16.83 ± 3.10 vs. 18.96 ± 3.59 L/min, p = 0.04) and systemic oxygen (O2) delivery (3.37 ± 0.84 vs. 3.47 ± 0.89 L/min, p = 0.04) in hypoxia compared to normoxia. Arterial-venous O2 difference (a-vDO2) was lower in hypoxia (137 ± 21 vs. 112 ± 19 mL/l, p = 0.03). The increases in peak CO from normoxia to hypoxia were negatively correlated with changes in mean arterial pressure (MABP) (p < 0.05). These preliminary data indicate that the rise in CO was not sufficient to prevent single-leg performance loss at moderate altitude and that enhanced baroreceptor activity might limit CO increases in acute hypoxia, likely by reducing sympathetic activation. Since the systemic O2 delivery was enhanced and the calculated a-vDO2 reduced in moderate hypoxia, a potential diffusion limitation cannot be excluded.

Power Profiling in U23 Professional Cyclists During a Competitive Season.

PURPOSE: The aim of this study was to investigate changes in the power profile of U23 professional cyclists during a competitive season based on maximal mean power output (MMP) and derived critical power (CP) and work capacity above CP (W') obtained during training and racing. METHODS: A total of 13 highly trained U23 professional cyclists (age = 21.1 [1.2] y, maximum oxygen consumption = 73.8 [1.9] mL·kg-1·min-1) participated in this study. The cycling season was split into pre-season and in-season. In-season was divided into early-, mid-, and late-season periods. During pre-season, a CP test was completed to derive CPtest and W'test. In addition, 2-, 5-, and 12-minute MMP during in-season were used to derive CPfield and W'field. RESULTS: There were no significant differences in absolute 2-, 5-, and 12-minute MMP, CPfield, and W'field between in-season periods. Due to changes in body mass, relative 12-minute MMP was higher in late-season compared with early-season (P = .025), whereas relative CPfield was higher in mid- and late-season (P = .031 and P = .038, respectively) compared with early-season. There was a strong correlation (r = .77-.83) between CPtest and CPfield in early- and mid-season but not late-season. Bland-Altman plots and standard error of estimates showed good agreement between CPtest and in-season CPfield but not between W'test and W'field. CONCLUSION: These findings reveal that the power profile remains unchanged throughout the in-season, except for relative 12-minute MMP and CPfield in late-season. One pre-season and one in-season CP test are recommended to evaluate in-season CPfield and W'field.

6-week High-intensity Interval Training (HIIT) of the Lower Extremities Improves VO2max of the Upper Extremities.

High intensity interval training (HIIT) is widely used to improve VO2max. The purpose of this study was to examine if lower extremity HIIT resulted in improved maximal oxygen uptake (VO2max) and peak power output (PPO) of the upper extremities. Twenty healthy and trained participants (11 female and 9 male, VO2max 3160±1175 ml/min) underwent a 6-week HIIT program of the lower extremities on a cycle ergometer. Before and after the training period a maximal cycle ergometry (CE) and a maximal hand crank ergometry (HCE) were conducted to determine VO2max and PPO. Additionally, hematological parameters were determined. Increases in VO2max of the lower extremities (3160±1175 to 3449±1231 ml/min, p<0.001, η2p=0.779) as well as of the upper extremities (2255±938 to 2377±1015 ml/min, p=0.010, η2p=0.356) from pre- to post-test were found. PPO of the lower extremities increased (243±95 to 257±93 W, p<0.001, η2p=0.491), whereas it remained unchanged for the upper extremities (103±50 to 108±54 W, p=0.209, η2p=0.150). All hematological parameters increased. The results demonstrate that VO2max of the upper extremities increased after 6-weeks of cycling HIIT. However, upper body PPO was unchanged.

Cardiorespiratory and Metabolic Responses During Graded Exercise in Normobaric and Hypobaric Hypoxia.

Background: The study investigated submaximal exercise responses during an acute exposure to normobaric hypoxia (NH) versus hypobaric hypoxia (HH) focusing on different exercise intensities. Methods: Eight recreationally trained male subjects (age 23 ± 3 years) performed submaximal cycling exercise at three different intensity levels (100, 150, and 200 W) in NH (simulated altitude 3150 m) and HH (terrestrial high altitude, 3150 m) in a cross-over study design. Cardiorespiratory parameter, blood lactate concentration, and ratings of perceived exertion were determined at each intensity level. Results: Cardiorespiratory parameters, arterial oxygen saturation, and ratings of perceived exertion did not differ between NH and HH except for the higher ventilatory equivalent for oxygen in HH compared to NH (25.9 ± 1.3 vs. 24.6 ± 1.0 at 100 W, 28.0 ± 1.6 vs. 27.1 ± 1.6 at 150 W, 32.1 ± 3.9 vs. 31.3 ± 3.6 at 200 W, p = 0.03). Blood lactate concentration tended to be higher in HH compared to NH (1.8 ± 0.9 mmol/L vs. 1.7 ± 0.8 mmol/L at 100 W, 3.2 ± 1.8 mmol/L vs. 2.8 ± 1.6 mmol/L at 150 W, 6.0 ± 3.1 mmol/L vs. 5.5 ± 3.0 mmol/L at 200 W, p = 0.08) with a significant interaction effect for exercise intensity (p = 0.02). Conclusions: Cycling during acute exposure to NH appears to result in equivalent cardiorespiratory responses to HH. The more pronounced lactate accumulation in HH should be a topic of future research.

Mortality in Different Mountain Sports Activities Primarily Practiced in the Summer Season-A Narrative Review.

Millions of people engage in mountain sports activities worldwide. Although leisure-time physical activity is associated with significant health benefits, mountain sports activities also bear an inherent risk for injury and death. However, death risk may vary across various types of mountain sports activities. Epidemiological data represent an important basis for the development of preventive measures. Therefore, the aim of this review is to compare mortality rates and potential risk factors across different (summer) mountain sports activities. A comprehensive literature search was performed on the death risk (mortality) in mountain sports, primarily practiced during the summer season, i.e., mountain hiking, mountain biking, paragliding, trekking, rock, ice and high-altitude climbing. It was found that the death risk varies considerably between different summer mountain sports. Mortality during hiking, trekking and biking in the mountains was lower compared to that during paragliding, or during rock, ice or high-altitude climbing. Traumatic deaths were more common in activities primarily performed by young adults, whereas the number of deaths resulting from cardiovascular diseases was higher in activities preferred by the elderly such as hiking and trekking. Preventive efforts must consider the diversity of mountain sports activities including differences in risk factors and practitioners and may more particularly focus on high-risk activities and high-risk individuals.

Functional Vs. Running Low-Volume High-Intensity Interval Training: Effects on VO2max and Muscular Endurance.

The purpose of the study was to assess if high-intensity interval training (HIIT) using functional exercises is as effective as traditional running HIIT in improving maximum oxygen uptake (VO2max) and muscular endurance. Fifteen healthy, moderately trained female (n = 11) and male (n= 4) participants (age 25.6 ± 2.6 years) were assigned to either running HIIT (HIIT-R; n = 8, 6 females, 2 males) or functional HIIT (HIIT-F; n = 7, 5 females, 2 males). Over a four-week period, both groups performed 14 exercise sessions of either HIIT-R or, HIIT-F consisting of 3-4 sets of low-volume HIIT (8x 20 s, 10 s rest; set rest: 5 min). Training heart rate (HR) data were collected throughout all training sessions. Mean and peak HR during the training sessions were significantly different (p = 0.018 and p = 0.022, respectively) between training groups, with HIIT-F eliciting lower HR responses than the HIIT-R. However, despite these differences in exercise HR, VO2max improved similarly (~13% for the HIIT-R versus ~11% for the HIIT-F, p=0.300). Muscular endurance (burpees and toes to bar) significantly improved (p =0.004 and p = 0.001, respectively) independent of training modality. These findings suggest that classic running HIIT and functional HIIT both improve VO2max and affect muscular endurance to the same extent despite a lower cardiovascular strain in the functional protocol.

The use of medication and alcohol in recreational downhill skiers: Results of a survey including 816 subjects in Tyrol.

OBJECTIVE: The aim of this study was to collect data on the medication and alcohol use in recreational downhill skiers. DESIGN: Cross-sectional study. METHODS: The study was conducted during the 2014 winter season in different ski resorts in Tyrol, Austria. Participants were asked to complete a brief survey including questions about basic anthropometric data (age, stature, weight) the use of medication (yes/no) and alcohol intake on the skiing day or the day before (yes/no). RESULTS: In total, 816 persons with an age between 6-87 years were surveyed. In general, 22% of the male and 20% of the female recreational downhill skiers reported the use of medication. In the age group >40 years, half of the respondents were taking medication on a regular basis. 30% of males and 16% of females reported to consume alcohol on the skiing day whereas more than 50% drank alcohol on the evening before skiing the next day. 63% of those under medication concomitantly consumed alcohol. CONCLUSIONS: The findings confirm a high prevalence of medication use and alcohol consumption in recreational downhill skiers. Even more importantly, 63% of skiers under medication concomitantly consumed alcohol. Considering the fact that only a small amount of alcohol can already affect motor and cognitive skills, it may be strongly assumed that the risk for skiing injuries is increased with alcohol consumption. Side effects of simultaneous intake of drugs and alcohol may include hypotension, vertigo and collapse which are thought to be associated with increased risks of skiing falls and injuries.

Mortality in Different Mountain Sports Activities Primarily Practiced in the Winter Season-A Narrative Review.

Annually, millions of people engage in mountain sports activities all over the world. These activities are associated with health benefits, but concurrently with a risk for injury and death. Knowledge on death rates is considered important for the categorization of high-risk sports in literature and for the development of effective preventive measures. The death risk has been reported to vary across different mountain sports primarily practiced in the summer season. To complete the spectrum, the aim of the present review is to compare mortality rates across different mountain sports activities primarily practiced in winter. A comprehensive literature search was performed on the death risk (mortality) during such activities, i.e., alpine (downhill) skiing, snowboarding, cross-country skiing, ski touring, and sledging. With the exception of ski touring (4.4 deaths per 1 million exposure days), the mortality risk was low across different winter sports, with small activity-specific variation (0.3-0.8 deaths per 1 million exposure days). Traumatic (e.g., falls) and non-traumatic (e.g., cardiac death) incidents and avalanche burial in ski tourers were the predominant causes of death. Preventive measures include the improvement of sport-specific skills and fitness, the use of protective gear, well-targeted and intensive training programs concerning avalanche hazards, and sports-medical counseling for elderly and those with pre-existing diseases.

Physiological Factors Associated With Declining Repeated Sprint Performance in Hypoxia.

Gatterer, H, Menz, V, Untersteiner, C, Klarod, K, and Burtscher, M. Physiological factors associated with declining repeated sprint performance in hypoxia. J Strength Cond Res 33(1): 211-216, 2019-Performance loss in hypoxia might not only be caused by reduced oxygen availability, but might also be influenced by other factors, as for example, oxidative stress, perceived exertion, or breathing patterns. This study aimed to investigate the influence of these factors on running performance during hypoxic and normoxic shuttle-run sprinting. Eight male amateur soccer players performed shuttle-run sprints in hypoxia (FiO2 ∼14.8%) and normoxia (random order). Each session comprized 3 sets of 5 × 10 seconds back and forth sprints (4.5 m), with recovery times between repetitions and sets of 20 seconds and 5 minutes, respectively. Sprinting distance, acceleration patterns, heart rate (HR) and breathing frequency were measured during each session (Zephyr-PSM Training System). Redox state and lactate concentration ([La]) were determined before and after each session, whereas rating of perceived exertion (RPE) was assessed after the sprint sessions. Overall distance covered was similar during hypoxia and normoxia sprinting (Δ -8.3 ± 14.3 m, 95% CI -20.2 to 3.6, p > 0.05). During the third set, distance tended to be reduced in hypoxia compared with normoxia (169 ± 6 m, 95% CI 164-174 vs. 175 ± 4 m, 95% CI 171-178, p = 0.070). Differences in breathing frequency during sprinting in hypoxia and normoxia were associated with individual reductions in sprinting distance (r = -0.792, p = 0.019). Despite a somewhat lower running distance during the third set and similar [La], RPE, HR, and redox responses, the preserved overall running distance indicates that the training stimulus might be enhanced in hypoxia compared with normoxia. Alteration of the respiratory patterns during repeated sprinting in hypoxia might be one factor, besides others, responsible for a potential performance loss. It could be hypothesized that respiratory pattern adaptations are involved in potential performance improvements after hypoxia repeated sprint training.

Exercise Performance, Muscle Oxygen Extraction and Blood Cell Mitochondrial Respiration after Repeated-Sprint and Sprint Interval Training in Hypoxia: A Pilot Study.

This study aimed to investigate and compare the effects of repeated-sprint (RSH) and sprint interval training in hypoxia (SIH) on sea level running and cycling performance, and to elucidate potential common or divergent adaptations of muscle perfusion and -oxygenation as well as mitochondrial respiration of blood cells. Eleven team-sport athletes performed either RSH (3x5x10s, 20s and 5min recovery between repetitions and sets) or SIH (4x30s, 5min recovery) cycling training for 3weeks (3 times/week) at a simulated altitude of 2,200m. Before and three days after the training period, a Wingate and a repeated cycling sprint test (5x6s, 20s recovery) were performed with a 30min resting period between the tests. Four to five days after the training, participants performed a repeated running sprint test (RSA, 6x17m back and forth, 20s recovery) and a Yo-Yo intermittent recovery test (YYIR2) with 1 hour active recovery between tests. The order of the tests as well as the duration of the resting periods remained the same before and after the training period. During the cycling tests near-infrared spectroscopy was performed on the vastus lateralis. In four participants, mitochondrial respiration of peripheral blood mononuclear cells (PBMC) and platelets was measured before and after training. YYIR2 running distance increased by +96.7 ± 145.6 m after RSH and by +100.0 ± 51.6 m after SIH (p = 0.034, eta² = 0.449). RSA mean running time improved by -0.138 ± 0.14s and -0.107 ± 0.08s after RSH and SIH respectively (p = 0.012, eta² = 0.564). RSH compared to SIH improved re-oxygenation during repeated sprinting. Improvements in repeated cycling were associated with improvements in re-oxygenation (r = 0.707, p <0.05). Mitochondrial electron transfer capacity normalized per PBMC count was decreased in RSH only. This study showed that cycling RSH and SIH training improves sea-level running performance. Our preliminary results suggest that RSH and SIH training results in different patterns of muscular oxygen extraction and PBMC mitochondrial respiration, without effect on platelets respiration.

[Secondary Full Title: Effects of high intensity interval training in plain and uphill regarding physical performance]. / Effekte eines hochintensiven Intervalltrainings in der Ebene und in ansteigendem Gelände hinsichtlich der physischen Leistungsfähigkeit.

BACKGROUND: As the number of HIITs is increasing in competitive and non-competitive sports, the risk of injuries and overload is increasing. There are no scientific data to support specific recommendations in regard to intensity, duration, number of intervals and gradient for HIIT that result in improved muscular parameters in athletes. Therefore the aim of this study was to compare HIIT in plain and uphill exercise, with respect to exercise tolerance and improvements in performance (VO2max and 800 m running time in the plain and uphill). VOLUNTEERS AND METHODS: 17 well-trained sport students (10 females, 7 males; Ø VO2max: 53.7 ml/min/kg) were randomly assigned to the plain group (plain; GE) (n = 8) or the uphill group (hill, GB) (n = 9). In the four weeks of training, all subjects completed 14 HIIT sessions. Each session consisted of 8 × 2 min running at 90 - 95 % of the maximal heart rate (HRmax), separated by 2 min recovery periods (work/rest ratio: 1:1). Before the intervention phase, subjects performed treadmill spirometry, a 800 m field test in the plain, as well as an 800 m uphill field test to determine baseline performance. One week after the intervention period, all subjects completed a retest of all measurements and tests. After the intervention, all subjects completed a questionnaire by giving their level of perceived exertion during training, using the BORG scale. RESULTS: In GE, three subjects dropped out of the study because of overtraining. In GB, two subjects did not complete the study because of time constraints. The evaluation of the perceived exertion of the training in flat terrain showed a trend (p = 0.08; t = - 1.96) towards being perceived as more exhausting then in hilly terrain. A four week HIIT showed significant improvements in VO2max by 5.2 % (p = 0.02; t = - 2.76), and a reduction in the running time in the plain by 4.6 % (p = 0.01; t = 3.48) and uphill by 6.3 % (p = 0.02; t = 2.77). No significant group effect was detected. DISCUSSION AND CONCLUSION: In this study, the application of HIIT leads to significant improvements in the performance of well-trained athletes. There is no evidence that the mode of training influenced the running improvements. However, uphill training tends to be better tolerated by the athletes.

Influence of high-intensity interval training on ventilatory efficiency in trained athletes.

The aim of this study was to investigate the effects of 3 weeks high-intensity interval training (HIIT) on ventilatory efficiency (VE/VCO2 slope) in endurance athletes. Sixteen male well-trained (67.72 ml kg min-1) athletes participated in this study. Each participant performed an incremental exercise test with gas analysis (i.e. VE, VO2) and a 400 m running field test (T400m) before and after the 3 weeks intervention period. HIIT group (HIITG) performed 11 HIIT sessions consisting of four 4-min interval bouts at an exercise intensity of 90-95% of the VO2max, separated by 4-min active recovery periods (work/rest ratio = 1:1). No significant differences were found in the parameters studied. Ventilatory efficiency (up to VT2 and up to exhaustion) did not show any change in HIITG after training intervention (ES = 0.24 HIITG; ES = 0.21 CG). No significant changes were observed on ventilation (VEmax; ES = 0.38). VO2max and T400 m did not show a significant improvement after the training period (no interaction time × group, p < .05) (ES = 0.43 and ES = 0.75 respectively). These results do not support the hypothesis that 3 weeks of HIIT could modify the ventilatory efficiency response in well-trained athletes. Furthermore, they show the lack of relationship between ventilatory efficiency and sport performance.

Effect of Qigong exercise on cognitive function, blood pressure and cardiorespiratory fitness in healthy middle-aged subjects.

OBJECTIVE: To investigate effects of Qigong exercise on cognitive function, blood pressure and cardiorespiratory fitness in healthy middle-aged subjects. METHODS: Study part 1 examined the effects of Qigong exercise in 12 subjects (5 males, 7 females, aged 52.2±7.1years) who performed Qigong for 8 weeks (60min sessions, 3 times/week). Study part 2 evaluated the detraining effects 12 weeks after cessation of Qigong. Cognitive function (Digit Span Forward and Backward Test, Trail Making Tests part A and B), blood pressure, and exercise performance were determined at baseline, immediately after the training programme, and after the detraining period. RESULTS: Qigong exercise showed a significant improvement of Trail Making Tests part A (p=0.04), systolic blood pressure (p=0.001), diastolic blood pressure (p=0.005), mean arterial pressure (p<0.001), and maximal workload (p=0.032). Twelve weeks after cessation, Trail Making Tests part A, systolic blood pressure, diastolic blood pressure, mean arterial pressure, and maximal workload had returned to baseline (p=0.050, 0.007, 0.001, 0.001, and 0.017, compared to after the training, respectively). CONCLUSION: These results suggest that Qigong exercise effectively improved attention, brain processing speed, blood pressure and maximal workload. However, these improvements disappeared 12 weeks after cessation of Qigong. Consequently, performing Qigong regularly is important to maintain related health effects.

Is acute mountain sickness related to trait anxiety? A normobaric chamber study.

INTRODUCTION: Some mountaineers are more prone to the occurrence of acute mountain sickness (AMS) than others. State anxiety during altitude exposure might be associated with AMS development. We hypothesized that trait anxiety might be higher in AMS cases compared to non-AMS cases. The aim of the present study was to study the relationship between AMS development and trait anxiety. METHODS: In an observational study design, AMS incidence during a 12-hour exposure to normobaric hypoxia (FiO2=12.6%, equivalent to 4500m) was determined by the Lake Louise Scoring System. Trait anxiety (State Trait Anxiety Inventory) and confounding variables were assessed in a follow-up questionnaire (37months after hypoxic exposure). RESULTS: Twenty nine participants returned the follow-up questionnaire. AMS incidence was 38%. Both unadjusted and adjusted logistic regression analyses did not reveal trait anxiety as a significant variable in relation to AMS. DISCUSSION: Based on the findings of this preliminary study, there is no evidence that AMS development under normobaric conditions is related to trait anxiety. Differences to previous studies might be explained by the type of hypoxia, by different sample characteristics and by considering sleep disturbances in the calculation of the AMS score. However, future studies with larger sample sizes may help to clear the relationship between AMS development and the personality factor anxiety.

Seven Passive 1-h Hypoxia Exposures Do Not Prevent AMS in Susceptible Individuals.

PURPOSE: The present study evaluated the effects of a preacclimatization program comprising seven passive 1-h exposures to 4500-m normobaric hypoxia on the prevalence and severity of acute mountain sickness (AMS) during a subsequent exposure to real high altitude in persons susceptible to AMS. METHODS: The project was designed as a randomized controlled trial including 32 healthy female and male participants with known susceptibility to AMS symptoms. After baseline measurements, participants were randomly assigned to the hypoxia or the control group to receive the preacclimatization program (seven passive 1-h exposures within 7 d to normobaric hypoxia or sham hypoxia). After completing preacclimatization, participants were transported (bus, cog railway) to real high altitude (3650 m, Mönchsjoch Hut, Switzerland) and stayed there for 45 h (two nights). Symptoms of AMS and physiological responses were determined repeatedly. RESULTS: AMS incidence and severity did not significantly differ between groups during the high-altitude exposure. In total, 59% of the hypoxia and 67% of the control group suffered from AMS at one or more time points during the high-altitude exposure. Hypoxic and hypercapnic ventilatory responses were not affected by the preacclimatization program. Resting ventilation at high altitude tended to be higher (P = 0.06) in the hypoxia group compared with the control group. No significant between-group differences were detected for heart rate variability, arterial oxygen saturation, and hematological and ventilatory parameters during the high-altitude exposure. CONCLUSION: Preacclimatization using seven passive 1-h exposures to normobaric hypoxia corresponding to 4500 m did not prevent AMS development during a subsequent high-altitude exposure in AMS-susceptible persons.

Cardiorespiratory Effects of One-Legged High-Intensity Interval Training in Normoxia and Hypoxia: A Pilot Study.

A higher-than-average maximal oxygen consumption (VO2max), is closely associated with decreased morbidity and mortality and improved quality of life and acts as a marker of cardiorespiratory fitness. Although there is no consensus about an optimal training method to enhance VO2max, nevertheless training of small muscle groups and repeated exposure to hypoxia seem to be promising approaches. Therefore, this study was aimed at gaining innovative insights into the effects of small muscle group training in normoxia and hypoxia. Thirteen healthy participants were randomly assigned to the hypoxic (HG, n = 7) or normoxic (NG, n = 6) training group. Both groups completed nine high-intensity interval training sessions in 3 wks. The NG performed the training in normoxia (FiO2: 0.21; ~ 600 m) and the HG in hypoxia (FiO2: 0.126; ~ 4500 m). Each session consisted of 4 x 4 min one-legged cycling at 90% of maximal heart rate separated by 4 min recovery periods. Before and after the intervention period, VO2max and peak power output (Wmax) and responses to submaximal cycling (100 and 150 watts) were assessed in a laboratory cycling test. Peak power output significantly improved within both groups (9.6 ± 4.8% and 12.6 ± 8.9% for HG and NG, respectively) with no significant interaction (p = 0.277). However, VO2max only significantly increased after training in hypoxia from 45.4 ± 10.1 to 50.0 ± 9.8 ml/min/kg (10.8 ± 6.0%; p = 0.002) with no significant interaction (p = 0.146). The maximal O2-pulse improved within the HG and demonstrated a significant interaction (p = 0.040). One-legged cycling training significantly improved VO2max and peak power output. Training under hypoxic conditions may generate greater effects on VO2max than a similar training in normoxia and is considered as a promising training method for improving cardiorespiratory fitness. Key pointsNine sessions of one-legged high-intensity interval training significantly improved physical fitness.One-legged hypoxic training significantly improved Wmax, VO2max and submaximal performance.One-legged training in normoxia only improved Wmax but did not significantly improve VO2max and submaximal performance.