Comparing Post-Exercise Hypotension after Different Sprint Interval Training Protocols in a Matched Sample of Younger and Older Adults

This study assessed the post-exercise hypotension (PEH) effect in a sample of matched young and older adults after different sprint interval training (SIT) protocols. From forty-three participants enrolled in this study, twelve younger (24 ± 3 years) and 12 older (50 ± 7 years) participants, matched for the body mass index, systolic blood pressure, and VO₂max-percentiles, were selected. The participants completed two SIT protocols consisting of 4 × 30 s exercise bouts interspersed by either one (SIT1) or three minutes (SIT3) of active rest. The peripheral systolic (pSBP) and diastolic (pDBP) blood pressure, central systolic (cSBP) and diastolic (cDBP) blood pressure, pulse wave velocity (PWV), and heart rate (HR) were obtained before and at different measurement time points (t5, t15, t30, t45) after the exercise. No significant time × group interactions were detected in pSBP (p = 0.242, η² = 0.060), pDBP (p = 0.379, η² = 0.046), cSBP (p = 0.091, η² = 0.861), cDBP (p = 0.625, η² = 0.033), PWV (p = 0.133, η² = 0.076), and HR (p = 0.190, η² = 0.123) after SIT1. For SIT3 no significant time × group interactions could be detected for pSBP (p = 0.773, η² = 0.020), pDBP (p = 0.972, η² = 0.006), cSBP (p = 0.239, η² = 0.060), cDBP (p = 0.535, η² = 0.036), PWV (p = 0.402, η² = 0.044), and HR (p = 0.933, η² = 0.009). Matched samples of young and older adults reveal similar PEH effects after HIIT. Accordingly, age does not seem to affect PEH after SIT. These results show that rest interval length and age modulate the PEH effect after SIT.

Gaming for better health? Comparison of cardiorespiratory and hemodynamic responses of exergaming with moderate endurance exercise

Funding Acknowledgements

Type of funding sources: None.

Introduction

Exergames are interactive video games that require the player to move their body to progress through the game. Even though numerous studies have determined a higher exercise intensity in exergames compared to sedentary videogames, the literature remains equivocal as to whether exergames elicit intensity levels that result in relevant physiological responses. The aim of the present study was to assess whether an exergaming session (ES) in an innovative exergame represents a physiological relevant exercise stimulus capable of producing favorable hemodynamic responses similar to moderate endurance exercise (MEE). Therefore, cardiovascular responses during and after an ES and an ET were assessed and compared.

Methods

Twenty-seven healthy young adults aged 25±4 years (48% female; BMI 23.0±2.1 kg/m2) participated in the study. The Maximum heart rate (HRmax) and the maximum oxygen consumption (VO2max) were determined during a cardiopulmonary exercise test on a treadmill. Furthermore, participants completed both a typical MEE (35 minutes, 65% of HRmax) on a treadmill and an ES (28 minutes). Heart rate (HR) and oxygen consumption were recorded during both training sessions. Both before and during the 45 minutes after the training sessions, the peripheral and central blood pressure (BP) were assessed.

Results

HR and oxygen consumption were significantly higher during ES than during MEE (p<0.001). Throughout the ES, the participants achieved a mean HR of 86±4 % of HRmax. Mean oxygen consumption reached 66±5 % of VO2max. 45 Minutes after the ES, there was a significant decrease in peripheral systolic (-6.2±2.9 mmHg; p<0.001) and diastolic (-4.8±5.7 mmHg; p<0.001), as well as in central systolic (-4.9±5.4 mmHg; p<0.001) and diastolic (-4.8±5.2 mmHg; p<0.001) BP compared to baseline. After MEE, only the peripheral diastolic (-2.3±3.4 mmHg; p=0.003), and central diastolic (-2.2±3.8 mmHg; p=0.006) pressure were significantly lower than the resting values before the exercise. The interaction effects showed significant differences in peripheral and central systolic BP as well as in peripheral diastolic BP (p=0.05).

Conclusion

The ES represents a vigorous exercise stimulus that triggers relevant peripheral and central BP reactions that are more pronounced than after an MEE. Exergaming may therefore be a promising tool for the prevention of cardiovascular diseases.

Manipulating rest interval length in sprint interval training alters post-exercise hypotension and within-session oxygen consumption

Funding Acknowledgements

Type of funding sources: None.

Introduction

It is well documented that sprint interval training (SIT) elicits similar or even superior health and performance benefits compared to continuous aerobic training, albeit a significantly reduced time commitment. A distinctive feature of intermittent exercise training is the possibility to modulate the different training variables resulting in numerous different protocols. This makes this training approach infinitely variable and individually adjustable. The purpose of this study was to examine the effects of manipulating the rest interval length during SIT on post-exercise hypotension and within-session oxygen consumption.

Methods

Thirty healthy adults (aged 30.9 ± 8.7 years; BMI 22.1 ± 2.3 kg/m2; 14 males, 16 females) participated in this study. All participants completed two SIT protocols consisting of 4x 30-seconds all-out cycling sprints interspersed by either 1 (R1) or 3 (R3) minutes of active recovery. Both before and throughout the 45 minutes after the training, peripheral systolic (pSBP) and diastolic (pDBP) blood pressure, central systolic (cSBP) and diastolic (cDBP) blood pressure, pulse wave velocity (PWV), and heart rate (HR) were assessed. Throughout the SIT protocols, oxygen consumption (VO2) was continuously monitored.

Results

Only after R3 a significant reduction in pSBP, pDBP, cSBP, cDBP, and PWV could be detected. Significant interaction effects could be detected in pSBD, pDBP, cSBP, cDBP, and PWV. HR significantly increased after both conditions (Table 1.). No significant (p>0.05) differences in time spent at 75%, 85%, 95%, and 100% of maximal VO2 between R1 and R3 could be detected.

Conclusion

Rest interval manipulation seems to affect hemodynamic responses to SIT with longer resting intervals resulting in more substantial post-exercise hypotension effects. Time spent at a high percentage of maximal VO2 was not attenuated by rest interval manipulation. These results add crucial information for the prescription of SIT.

Optimizing sprint interval exercise for post-exercise hypotension: A randomized crossover trial

This study aimed to examine the effects of manipulating the rest intervals during sprint interval training (SIT) on post-exercise hypotension and within-session oxygen consumption.Thirty healthy, trained adults (aged 30.9 ± 8.7 years; 14 males, 16 females; BMI 22.1 ± 2.3 kg/m²; VO₂max 50.7 ± 7.8 ml/kg/min) completed two different SIT protocols (4x 30-seconds all-out cycling sprints) with a one-week washout period. Sprint bouts were separated by either 1 (R1) or 3 (R3) minutes of active recovery. Both before and throughout the 45 minutes after the training, peripheral systolic (pSBP) and diastolic (pDBP) blood pressure, central systolic (cSBP) and diastolic (cDBP) blood pressure, aortic pulse wave velocity (aPWV), stroke volume (SV), and heart rate (HR) were assessed. Throughout the SIT protocols, oxygen consumption (VO₂) was monitored.There were no significant differences in time spent at 75%, 85%, 95%, and 100% of maximal VO₂ between R1 and R3. After R3, there was a significant reduction in pSBP, pDBP, cSBP, cDBP, and aPWV. After R1, there were no changes in the respective parameters. There were significant interaction effects in pSBD (p<0.001), pDBP (p<0.001), cSBP (p<0.001), cDBP (p=0.001), and aPWV (p=0.033). HR significantly increased after both conditions. Only R1 resulted in a significant reduction in SV.Longer resting intervals during SIT bouts seem to result in more substantial post-exercise hypotension effects. Time spent at a high percentage of maximal VO₂ was not affected by rest interval manipulation.

Gaming Instead of Training? Exergaming Induces High-Intensity Exercise Stimulus and Reduces Cardiovascular Reactivity to Cold Pressor Test

Introduction

The present study assessed if an exercise session in an innovative exergame can modulate hemodynamic reactivity to a cold pressor test (CPT) to a similar extent as a typical moderate endurance training (ET). Furthermore, cardiorespiratory, and affective responses of an exergame session and an ET were compared.

Methods

Twenty-seven healthy participants aged 25 ± 4 years (48% female; BMI 23.0 ± 2.1 kg/m2) participated in this cross-sectional study. All participants completed both an ET on a treadmill and training in the ExerCube (ECT). HR and oxygen consumption were recorded during both training sessions. Before and after both exercise sessions, the hemodynamic reactivity to a CPT was determined.

Results

During ECT, HR, oxygen consumption, energy expenditure, and the metabolic equivalent of the task were significantly higher than those obtained during ET (p &lt; 0.001). With regard to the CPT, the participants showed significantly lower responses in peripheral systolic (p = 0.004) and diastolic blood pressure (p = 0.009) as well as central systolic (p = 0.002) and diastolic BP (P = 0.01) after ECT compared to ET. The same was true for pulse wave velocity (p = 0.039).

Conclusion

The ECT induced a significantly higher exercise stimulus compared to the ET. At the same time, it attenuated hemodynamic stress reactivity. The ECT presents a relevant training stimulus that modulates cardiovascular reactivity to stress, which has been proven as a predictor for the development of hypertension.

Trial Registration

ISRCTN registry, ISRCTN43067716, 14 April 2020, Trial number: 38154.

A Game-Based Approach to Lower Blood Pressure? Comparing Acute Hemodynamic Responses to Endurance Exercise and Exergaming: A Randomized Crossover Trial

The present randomized crossover study aimed to determine whether an exergaming session in an innovative, functional fitness game could be an effective exercise approach that elicits favorable blood pressure (BP) responses, such as a typical moderate endurance exercise (ET). Therefore, acute hemodynamic responses after a training session in the ExerCube and an ET on a treadmill were assessed and compared. Twenty-eight healthy recreational active participants (13 women; aged 24.8 ± 3.9 years) completed an exergaming session (EX) and an ET in a randomized and counterbalanced order. Before and throughout the 45 min after the training, the peripheral and central BP were measured. After the ET, there was a moderate decrease in both peripheral systolic (-1.8 mmHg; p = 0.14) and diastolic (-0.8 mmHg; p = 0.003), as well as central diastolic (-1.5 mmHg; p = 0.006) pressure compared to the resting value before the exercise. After the EX, there was a significant decrease in peripheral systolic (-6.3 mmHg; p < 0.001) and diastolic (-4.8 mmHg; p < 0.001), as well as central systolic (-5.8 mmHg; p < 0.001) and diastolic (-5.3 mmHg; p < 0.001) pressure compared to baseline. The interaction effects showed significant differences in peripheral and central systolic BP as well as in peripheral diastolic BP (p = 0.05). The EX seems to be an effective training approach that triggers relevant peripheral and central BP-responses, which are more pronounced than after a typical ET. Therefore, the ExerCube can be a time-efficient training tool to improve cardiovascular health.

Acute Effects of Heart Rate-Controlled Exergaming on Vascular Function in Young Adults

Objective: Acute and regular moderate-intensity endurance exercise (MIEE) is known to positively affect vascular function. The present study assessed if an exercise session in an innovative exergame called the ExerCube can induce similar vascular reactions as an MIEE session. Materials and Methods: Twenty-eight healthy recreationally active participants (13 females and 15 males; aged 24.8 ± 3.9 years; with body mass index 23.2 ± 2.3 kg/m²) completed an exergaming session (EGS) in the ExerCube (25 minutes) and an MIEE session on a treadmill (35 minutes, 65%-70% of maximal heart rate [HR]) in a randomized order. Both before and throughout the 45 minutes after the training sessions, pulse wave velocity (PWV), total peripheral resistance (TPR), stroke volume (SV), and HR were recorded. The study was approved by the Research Ethics Board of the Martin-Luther-Universität Halle-Wittenberg (Medical Faculty of the Martin-Luther-Universität 2019-177). Results: There were different hemodynamic responses to both types of exercises. PWV was significantly decreased 45 minutes after the EGS (P < 0.001). No significant changes were detected after MIEE (P = 0.109). TPR was significantly lower after both exercise sessions (P < 0.01). Only the EGS resulted in a significant decrease in SV 15 minutes after exercise (P < 0.001). The HR was significantly (P < 0.05) higher after both exercise sessions. After the EGS, the increase in HR was still significantly higher (P = 0.011) 45 minutes after the session. The interaction effects revealed significant differences in PWV (15 minutes, P = 0.035; 30 minutes, P = 0.004; and 45 minutes, P < 0.001), favoring the EGS. Conclusion: The EGS seems to induce a relevant exercise stimulus that can modulate vascular function. Therefore, this exergame may present an effective tool for prevention of cardiovascular diseases.

Correlation Properties of Heart Rate Variability during a Marathon Race in Recreational Runners: Potential Biomarker of Complex Regulation during Endurance Exercise

There is only very limited data examining cardiovascular responses in real-world endurance training/competition. The present study examines the influence of a marathon race on non-linear dynamics of heart rate (HR) variability (HRV). Eleven male recreational runners performed a self-paced marathon road race on an almost flat profile. During the race, heart rate and beat-to-beat (RR) intervals were recorded continuously. Besides HRV time-domain measurements, fractal correlation properties using short-term scaling exponent alpha1 of Detrended Fluctuation Analysis (DFA-alpha1) were calculated. The mean finishing time was 3:10:22 ± 0:17:56 h:min:s with a blood lactate concentration of 4.04 ± 1.12 mmol/L at the end of the race. Comparing the beginning to the end segment of the marathon race (Begin vs. End) significant increases could be found for km split time (p < .001, d = .934) and for HR (p = .010, d = .804). Significant decreases could be found for meanRR (p = .013, d = .798) and DFA-alpha1 (p = .003, d = 1.132). DFA-alpha1 showed an appropriate dynamic range throughout the race consisting of both uncorrelated and anti-correlated values. Lactate was consistent with sustained high intensity exercise when measured at the end of the event. Despite the runners slowing after halfway, DFA-alpha1 continued to fall to values seen in the highest intensity domain during incremental exercise testing in agreement with lactate assessment. Therefore, the discrepancy between the reduced running pace with that of the decline of DFA-alpha1, demonstrate the benefit of using this dimensionless HRV index as a biomarker of internal load during exercise over the course of a marathon race.

Adaptive High-Intensity Exergaming: The More Enjoyable Alternative to Conventional Training Approaches Despite Working Harder

Objective: The purpose of this study was to assess psychological and physiological responses to an exergaming session in the ExerCube (EX) and compare them with the responses of a moderate endurance run (ER). Materials and Methods: Twenty-eight healthy adults (13 women) aged 24.8 ± 3.8 years took part in this study. The first test day, participants performed a graded exercise test on a treadmill to determine maximal heart rate (HR) and lactate levels. The following test days 2 and 3, the participants completed an EX session and an ER on a treadmill in a randomized counterbalanced order. HR, rate of perceived exertion (RPE), and lactate levels were assessed during both sessions. After the sessions, the participants completed the "Physical Activity Enjoyment Scale" and the "Flow Short Scale." Results: The analysis of variance revealed that enjoyment (P = 0.036), flow (P = 0.042), RPE (P = 0.005), as well as mean and peak HR (P < 0.001) during the EX session were significantly higher compared with the ER. Gender did not affect the differences between the two conditions for mean HR (P = 0.61), maximal HR (P = 0.122), RPE (P = 0.862), flow (P = 0.376) nor enjoyment (P = 0.867). During the EX session, the lactate levels of all participants exceeded the individual lactate threshold (LT). During the ER, lactate values remained below the LT. Conclusion: The ExerCube presents both a physiological relevant exercise stimulus and a joyful gaming experience. Despite the higher exercise intensity achieved during the EX session, enjoyment was significantly higher compared with the ER. Therefore, the EX can be a promising and appealing tool to facilitate physical activity. Trial registration: ISRCTN registry, ISRCTN43067716, April 14, 2020. Trial number: 38154.

Utilizing Heart Rate Variability for Coaching Athletes During and After Viral Infection: A Case Report in an Elite Endurance Athlete

Background: Viral diseases have different individual progressions and can lead to considerable risks/long-term consequences. Therefore, it is not suitable to give general recommendations on a time off from training for athletes. This case report aims to investigate the relevance of detecting heart rate (HR) and HR variability (HRV) during an orthostatic test (OT) to monitor the progression and recovery process during and after a viral disease in an elite endurance athlete.

Methods: A 30-year-old elite marathon runner contracted a viral infection (upper respiratory tract infection) 4 weeks after a marathon race. RR intervals in HR time series in supine and standing positions were monitored daily in the morning. Analyzed parameters included HR, the time-domain HRV parameter root mean square of successive difference (RMSSD), peak HR (HRpeak) in a standing position, and the time to HR peak (tHRpeak).

Results: During the 6-day viral infection period, HR increased significantly by an average of 11 bpm in the supine position and by 22 bpm in the standing position. In addition, the RMSSD decreased from 20.8 to 4.2 ms, the HRpeak decreased by 13 bpm, and the tHRpeak increased by 18 s in the standing position significantly. There were no significant changes in the pre-viral infection RMSSD values in the supine position. The viral infection led to a significant change in HR and HRV parameters. The cardiac autonomic system reacted more sensitively in the standing position compared to the supine position after a viral infection in the present case study.

Conclusion: These data have provided supportive rationale as to why the OT with a change from supine to standing body position and the detection of different indicators based on HR and a vagal driven time-domain HRV parameter (RMSSD) is likely to be useful to detect viral diseases early on when implemented in daily routine. Given the case study nature of the findings, future research has to be conducted to investigate whether the use of the OT might be able to offer an innovative, non-invasive, and time-efficient possibility to detect and evaluate the health status of (elite endurance) athletes.

Comparison between bicycle ergometric interval and continuous training in patients early after coronary artery bypass grafting: A prospective, randomized study

Objectives:

Continuous and interval training have previously been compared in patients with cardiac diseases. However, data comparing the safety and effectiveness of the two exercise methods are lacking in patients early after coronary artery bypass grafting.

Methods:

In all, 120 patients were prospectively randomized in a 1:1 fashion approximately 17 days after coronary artery bypass grafting to an interval group or continuous group. All patients participated in bicycle ergometric training six times/week for 20 min each during a 3-week inpatient rehabilitation program. The combined primary endpoint was safety as defined by incidence of scar pain and cardiac events related to the exercise intervention. Secondary outcomes included the effect of the interventions on parameters such as heart rate and peak power output.

Results:

Four patients (12.1%) in the interval group reported pain on the saphenectomy scar as a result of the training intervention in comparison to six patients (20.0%) in the continuous group (χ² (1, n = 63) = 0.73, p = 0.393). No cardiac events were related to exercise intervention. No effect on heart rate was found during the intervention, nor was a difference observed between the groups. Peak power output, as one of the analyzed markers, improved significantly in both groups, but no differences were found between groups.

Conclusion:

Ergometry training performed as interval or continuous training was safe and effective regarding increase in physical fitness early after coronary artery bypass grafting in an inpatient rehabilitation setting, with no differences observed between the groups.

The New Way to Exercise? Evaluating an Innovative Heart-rate-controlled Exergame

Exergames may offer novel opportunities to expand physical activity. Most games, however, only result in low to moderate-intensity activities that are too low to allow relevant physical adjustments. In the present study, the exercise intensity of a new, heart rate controlled, functional fitness game was assessed. 28 subjects (aged 24.8±3.8 yrs; 46% female; BMI 23.2±2.3 kg/m2) were enrolled in this study. VO2max and maximal heart rate (HRmax) were assessed during a maximal graded exercise test on a treadmill and compared with the oxygen consumption (VO2) and heart rate (HR) during a game in the ExerCube.In the ExerCube, the subjects reached a peak HR of 187.43±9.22 bpm, which corresponds to 96.57±3.64% of their HRmax. The mean HR throughout the game was 167.11±10.94 bpm, corresponding to 86.07±4.33% of HRmax. VO2peak reached 41.57±5.09 ml/kg/min during the game in the ExerCube, which corresponds to 84.75±7.52% of VO2max. The mean VO2 consumption during the game reached 32.39±4.04 ml/kg/min, which corresponds to 66.01±5.09% of VO2max. The ExerCube provides a form of vigorous physical exercise. Due to its playful, immersive, and motivating nature, the ExerCube seems to be a promising tool to facilitate physical activity.

Recovery from Different High-Intensity Interval Training Protocols: Comparing Well-Trained Women and Men

Due to physiological and anatomical sex differences, there are variations in the training response, and the recovery periods following exercise may be different. High-intensity interval training (HIIT) protocols are well-suited to differentially investigate the course of recovery. This study was conducted to determine sex-specific differences in the recovery following HIIT intervals interspersed with recovery phases of different lengths. Methods: Well-trained cyclists and triathletes (n = 11 females, n = 11 males) participated in this study. There were no significant sex differences in maximal heart rate (HR), relative peak power to body mass and fat-free mass, training volume, and VO_2max-percentiles (females: 91.8 ± 5.5 %, males: 94.6 ± 5.4 %). A 30 s Wingate test was performed four times, separated by different active recovery periods (1, 3, or 10 min). Lactate, HR, oxygen uptake, and subjective rating of exertion and recovery were determined. Results: For the recovery time of three and ten minutes, men showed significantly higher lactate concentrations (p = 0.04, p = 0.004). Contrary, HR recovery and subjective recovery were significant slower in women than in men. Conclusion: During HIIT, women may be more resistant to fatigue and have a greater ability to recover metabolically, but have a slower HR and subjective recovery.

Der Eisenstoffwechsel und seine Bedeutung für das Höhentraining

Ein Eisenmangel und eine katabole Stoffwechsellage behindern die Zunahme des Gesamthämoglobins und damit einen Anstieg der Sauerstofftransportkapazität, sodass die Wirksamkeit des Höhentrainings herabgesetzt ist. Die Eisenhomöostase wird sehr fein durch das hepatische Hormon Hepcidin (HEPC) kontrolliert, welches die Eisenaufnahmefähigkeit der Darmzellen über ein spezielles Protein, dem Ferroportin, kontrolliert. Unter Hypoxie stimuliert das Protein HIF-1 α die Freisetzung des Erythropoitins (EPO). Unzureichende Eisenspeicher und/oder eine Vitamin-B12-Unterversorgung bei Athleten, besonders bei jungen Frauen, sind Wochen vor einem Höhentraining durch eine orale Eisen- und/oder Vitamin-B12-Substitution unter ärztlicher Kontrolle, aufzufüllen. Voraussetzung für eine leistungsfördernde Wirkung des Höhentrainings ist ein mehrmaliger Aufenthalt in mittleren Höhen von 1700 m bis 3000 m. Als Aufenthaltsdauer werden 350 h bis 500 h oder zwei bis drei Wochen empfohlen. Mangelnde Eisenverfügbarkeit und ein Energiedefizit können die Wirksamkeit des Höhentrainings negativ beeinflussen. Liegt aus medizinischer Sicht eine Eisenunterversorgung vor, dann wird zu einer oralen Supplementation vor und während des Höhentrainings geraten. Bei normaler Eisenverfügbarkeit führt die gesteigerte Hämatopoese durch EPO zur Zunahme des Gesamthämoglobins. Die Wirkung des hypoxieinduzierten Hämoglobinanstiegs ist nach dem Höhentraining auf drei bis vier Wochen begrenzt.

Exercise Training, Intermittent Fasting and Alkaline Supplementation as an Effective Strategy for Body Weight Loss: A 12-Week Placebo-Controlled Double-Blind Intervention with Overweight Subjects

BACKGROUND

Intermittent fasting (IF) combined with exercise has been suggested to enhance weight loss. However, both procedures might negatively influence acid-base status. The aim of this study was to determine the combined effects of IF, exercise training and alkaline supplementation in overweight subjects on body composition and running performance.

METHODS

80 overweight subjects of age 45.5 ± 7.8 years were assigned to IF or non-intermittent fasting (nIF). Furthermore, subjects were randomly assigned to take either an alkaline supplement (IF-v, nIF-v) or a placebo (IF-p, nIF-p) twice a day. All subjects performed a personalized endurance exercise program (3-4 times/week for 12 weeks). Body weight, body composition, running performance and acid-base parameters were determined before (pre) and after the 12-week program (post).

RESULTS

68 participants completed the study. There was a significant effect on body weight loss, body fat loss, visceral fat loss and running performance enhancement in all groups (p < 0.01) for pre and post measurements. Body weight decreased in all groups (IF-p: -5.80 ± 0.77 kg and nIF-p: -3.40 ± 0.58 kg; IF-v: -8.28 ± 0.75 kg and nIF-v: -5.59 ± 0.87 kg). In both dietary strategies, weight loss was significantly further enhanced by alkaline supplementation. The increase in running velocity was significantly higher in IF combined with alkaline supplementation (IF-v 1.73 ± 0.23 km/h and IF-p 0.97 ± 0.20 km/h). In addition, alkaline supplementation increased plasma HCO₃^- concentration and urinary pH.

CONCLUSION

Exercise training in combination with IF and alkaline supplementation is an effective strategy to reduce body weight and improve running performance in a 12-week intervention.

Effects of Acute Normobaric Hypoxia on Non-linear Dynamics of Cardiac Autonomic Activity During Constant Workload Cycling Exercise

Aim

Measurements of Non-linear dynamics of heart rate variability (HRV) provide new possibilities to monitor cardiac autonomic activity during exercise under different environmental conditions. Using detrended fluctuation analysis (DFA) technique to assess correlation properties of heart rate (HR) dynamics, the present study examines the influence of normobaric hypoxic conditions (HC) in comparison to normoxic conditions (NC) during a constant workload exercise.

Materials and Methods

Nine well trained cyclists performed a continuous workload exercise on a cycle ergometer with an intensity corresponding to the individual anaerobic threshold until voluntary exhaustion under both NC and HC (15% O₂). The individual exercise duration was normalized to 10% sections (10-100%). During exercise HR and RR-intervals were continuously-recorded. Besides HRV time-domain measurements (meanRR, SDNN), fractal correlation properties using short-term scaling exponent alpha1 of DFA were calculated. Additionally, blood lactate (La), oxygen saturation of the blood (SpO₂), and rating of perceived exertion (RPE) were recorded in regular time intervals.

Results

We observed significant changes under NC and HC for all parameters from the beginning to the end of the exercise (10% vs. 100%) except for SpO₂ and SDNN during NC: increases for HR, La, and RPE in both conditions; decreases for SpO₂ and SDNN during HC, meanRR and DFA-alpha1 during both conditions. Under HC HR (40-70%), La (10-90%), and RPE (50-90%) were significantly-higher, SpO₂ (10-100%), meanRR (40-70%), and DFA-alpha1 (20-60%) were significantly-lower than under NC.

Conclusion

Under both conditions, prolonged exercise until voluntary exhaustion provokes a lower total variability combined with a reduction in the amplitude and correlation properties of RR fluctuations which may be attributed to increased organismic demands. Additionally, HC provoked higher demands and loss of correlation properties at an earlier stage during the exercise regime, implying an accelerated alteration of cardiac autonomic regulation.

Non-linear dynamics of heart rate variability during incremental cycling exercise

Within the last years complex models of cardiovascular regulation and exercise fatigue have implemented heart rate variability (HRV) as a measure of autonomic nervous system. Using detrended fluctuation analysis (DFA) to assess heart rate correlation properties, the present study examines the influence of exercise intensity on total variability and complexity in non-linear dynamics of HRV. Sixteen cyclists performed a graded exercise test on a bicycle ergometer. HRV time domain measures and fractal correlation properties were analyzed using short-term scaling exponent alpha1 of DFA. Amplitude and complexity of HRV parameters decreased significantly. DFA-alpha1 increased from rest to low exercise intensity and showed an almost linear decrease from higher intensities until exhaustion. These findings support a qualitative change in self-organized heart rate regulation from a complex autonomic control at rest and low intensities towards a breakdown of the interaction in control mechanisms with non-autonomic heart rate control dominating at high intensities.

Non-linear dynamics of cardiac autonomic activity during cycling exercise with varied cadence

In recent years, complex models of cardiac regulation have integrated heart rate variability (HRV) as a measure of the cardiac autonomic activity during exercise. Using detrended fluctuation analysis (DFA) technique, the present study examines the influence of cycling cadence and exercise duration on non-linear dynamics of HRV. Sixteen trained cyclists performed a 60-minute exercise bout at 90% of the individual anaerobic threshold on a bicycle ergometer. Cadence was changed every 10 min (90-120-60-120-60-90 rpm). Heart rate (HR) and RR-intervals were recorded continuously during exercise. HRV time domain measures (meanRR, SDNN) and correlation properties were analyzed using short-term scaling exponent alpha1 of DFA. Moreover, blood lactate (La) and rating of perceived exertion (RPE) were recorded at regular intervals at the end of condition. HR, La and RPE increased significantly at 120 rpm compared to 60 rpm. In contrast, all analyzed HRV parameters (meanRR, SDNN, DFA-alpha1) showed a significant decrease during cycling at 120 rpm compared to 60 rpm. The comparison of the first and last 10 min with the same cadence indicates a significant increase in HR and RPE, but also a significant decrease in all analyzed HRV measures. The decrease of HRV values over time and in relation to the increase in cadence indicates a decrease in the overall variability as well as a reduction in complexity of the RR-interval-fluctuations due to the increased organismic demands. Therefore, the decrease of DFA-alpha1 might be associated with a withdrawal of the organismic system aiming at the maintenance of the homeostasis under the control of the central nervous system. In this context, non-linear HRV analyses provide a more systemic view of cardiac regulation during exercise.

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Zusammenfassung. Die Belastungssteuerung über die Herzfrequenzvariabilität (HRV) gewinnt im Kontext der Trainingsindividualisierung immer mehr an Bedeutung. Ziel der Studie war es, zu überprüfen, ob sich die über ein Herzfrequenzmessgerät auf der Basis der HRV ermittelten Intensitätsbereiche in Abhängigkeit der Leistungsfähigkeit über einen mehrwöchigen Trainingszyklus verändern. Freizeitläufer wurden für ein zwölfwöchiges Ausdauerprogramm rekrutiert. Vor und nach der Intervention wurde ein Stufentest mit Spirometrie durchgeführt. Zudem wurden die Belastungsvorgaben analysiert. Über den Interventionszeitraum hat sich die Unter- und Obergrenze der vorgegebenen Herzfrequenz in der niedrigsten Intensitätszone signifikant erhöht. Bezogen auf die Ausdauerleistung waren nach der Trainingsintervention zudem signifikante Verbesserungen zu verzeichnen. Die Anpassung der Herzfrequenzwerte an die veränderte Leistungsfähigkeit sichert in diesem Rahmen ein reizwirksames Training über eine mehrwöchige Trainingsintervention ab.

Four weeks of high cadence training alter brain cortical activity in cyclists

Exercise at different cadences might serve as potential stimulus for functional adaptations of the brain, because cortical activation is sensitive to frequency of movement. Therefore, we investigated the effects of high (HCT) and low cadence training (LCT) on brain cortical activity during exercise as well as endurance performance. Cyclists were randomly assigned to low and high cadence training. Over the 4-week training period, participants performed 4 h of basic endurance training as well as four additional cadence-specific exercise sessions, 60 min weekly. At baseline and after 4 weeks, participants completed an incremental exercise test with spirometry and exercise at constant load with registration of electroencephalogram (EEG). Compared with LCT, a greater increase of frontal alpha/beta ratio was confirmed in HCT. This was based on a lower level of beta activity during exercise. Both groups showed similar improvements in maximal oxygen consumption and power at the individual anaerobic threshold. Whereas HCT and LCT elicit similar benefits on aerobic performance, cycling at high pedalling frequencies enables participants to perform an exercise bout with less cortical activation.

Do Male And Female Cyclists' Cortical Activity Differ Before and During Cycling Exercise?

Although men and women are suggested to vary in resistance to fatigue, possible sex difference in its central component have rarely been investigated via electroencephalography (EEG). Therefore, we examined differences in cortical activity between male and female cyclists (n = 26) during cycling exercise. Participants performed an incremental test to derive the anaerobic threshold from the lactate power curve. In addition, cyclists' cortical activity was recorded with EEG before and during cycling exercise. Whereas women showed higher frontal alpha and beta activity at rest, no sex-specific differences of relative EEG spectral power occurred during cycling at higher intensity. Women and men's brains respond similarly during submaximal cycling, as both sexes show an inverted U-shaped curve of alpha power. Therefore, sex differences observable at rest vanish after the onset of exercise.

Effects of high vs. low cadence training on cyclists' brain cortical activity during exercise

OBJECTIVES

As brain cortical activity depends on cadence, exercise at different pedaling frequencies could provide efficient stimuli for functional adaptations of the brain. Therefore, the purpose of the study was to investigate the effects of cadence-specific training on brain cortical activity as well as endurance performance.

DESIGN

Randomized, controlled experimental trial in a repeated measure design.

METHODS

Male (n=24) and female (n=12) cyclists were randomly assigned to either a high cadence group (HCT), a low cadence group (LCT) or a control group (CON) for a 4 week intervention period. All groups performed 4h of basic endurance training per week. Additionally, HCT and LCT completed four cadence-specific 60min sessions weekly. At baseline and after 4 weeks subjects performed an incremental test with spirometry as well as an interval session (constant load; varying cadences) with continuous recording of electroencephalographic (EEG) rhythms.

RESULTS

In contrast to CON, HCT and LCT elicited similar improvements of maximal oxygen uptake and power at the individual anaerobic threshold. Additionally, there was a reduction of alpha-, beta- and overall-power spectral density in HCT, which was more pronounced at high cadences. Improvements of endurance performance were correlated with reductions of EEG spectral power at 90 and 120rpm.

CONCLUSIONS

Whereas high and low cadence training elicit similar improvements in endurance performance, brain cortical activity is especially sensitive to high cadence training. Its reduction can be interpreted in the sense of the neural efficiency hypothesis and might as well influence the sensation of central fatigue positively.

Does a run/walk strategy decrease cardiac stress during a marathon in non-elite runners?

OBJECTIVES

Although alternating run/walk-periods are often recommended to novice runners, it is unclear, if this particular pacing strategy reduces the cardiovascular stress during prolonged exercise. Therefore, the aim of the study was to compare the effects of two different running strategies on selected cardiac biomarkers as well as marathon performance.

DESIGN

Randomized experimental trial in a repeated measure design.

METHODS

Male (n=22) and female subjects (n=20) completed a marathon either with a run/walk strategy or running only. Immediately after crossing the finishing line cardiac biomarkers were assessed in blood taken from the cubital vein. Before (-7 days) and after the marathon (+4 days) subjects also completed an incremental treadmill test.

RESULTS

Despite different pacing strategies, run/walk strategy and running only finished the marathon with similar times (04:14:25±00:19:51 vs 04:07:40±00:27:15 [hh:mm:ss]; p=0.377). In both groups, prolonged exercise led to increased B-type natriuretic peptide, creatine kinase MB isoenzyme and myoglobin levels (p<0.001), which returned to baseline 4 days after the marathon. Elevated cTnI concentrations were observable in only two subjects. B-type natriuretic peptide (r=-0.363; p=0.041) and myoglobin levels (r=-0.456; p=0.009) were inversely correlated with the velocity at the individual anaerobic threshold. Run/walk strategy compared to running only reported less muscle pain and fatigue (p=0.006) after the running event.

CONCLUSIONS

In conclusion, the increase in cardiac biomarkers is a reversible, physiological response to strenuous exercise, indicating temporary stress on the myocyte and skeletal muscle. Although a combined run/walk strategy does not reduce the load on the cardiovascular system, it allows non-elite runners to achieve similar finish times with less (muscle) discomfort.

[Individualization of exercise load control for inpatient cardiac rehabilitation. Development and evaluation of a HRV-based intervention program for patients with ischemic heart failure]

BACKGROUND

The effective use of rehabilitation programs is of primary importance in order to improve the physical performance of cardiac disease patients. A modular program has been developed which is intended to structure and individualize conventional, exercise-based rehabilitation programs according to the individual needs and physical condition of each patient. The individualization of the program is based on detailed diagnostics before patients enter the program and daily measurements of heart rate variability (HRV) during cardiac rehabilitation.

METHODS

A total of 30 patients with ischemic heart disease were randomly assigned either to the intervention group (IG), completing the modular individualized rehabilitation program [n=15, mean age 54.4±4.2 years and mean left ventricular ejection fraction (LVEF) 28.53±6.25%) or to the control group (CG) taking part in the conventional rehabilitation program (n=15, mean age 56.4±4.4 years and mean LVEF 27.63±5.62). Before and after the intervention, cardiorespiratory fitness was assessed by measurement of maximal oxygen consumption (relative VO2max) during bicycle ergometry and the 6-minute walk test (6-MWT). Pre-post comparisons of cardiorespiratory fitness indicators were used to evaluate the effectiveness of the rehabilitation program. In addition to the results of the basic clinical investigations and the cardiorespiratory testing, results of standardized HRV measurements of 10 min at morning rest served as criteria for program individualization.

RESULTS

The relative VO2max increased significantly (p<0.05) in the IG whereas no change was found in the CG. Similar results were found for maximum power output during bicycle ergometry (p<0.01) and for 6-MWT distance (p<0.001). Although patients in the IG completed less aerobic exercise sessions than those in the CG (p<0.001) the physical performance of the IG improved significantly.

DISCUSSION

The results prove the effectiveness and efficacy of the modular individualized rehabilitation program. They further suggest the need for an individual program matrix instead of a maximum performance matrix in cardiac rehabilitation. Individualization should be based on clinical and performance diagnostics before and accompanying assessments of training condition, e.g. by HRV measurements, during rehabilitation programs. Each patient should only perform those intervention programs which match the results of the basic clinical investigation and additional analyses during rehabilitation.

Long-Range Correlations and Complex Regulation of Pacing in Long-Distance Road Racing

Purpose: To analyse time domain, spectral and fractal properties of speed regulation during half-marathon racing. Methods: In twenty-one male experienced runners high-resolution data on speed (V), stride frequency (SF) and stride length (SL) were assessed during half-marathon competition (21098 m). Performance times, time and frequency domain variability, spectral scaling exponent (beta) and fractal dimension (FD) of V, SF and SL were analysed. Results: V of 3.65±0.41 m·s-1, SF of 1.41±0.05 Hz and SL of 2.58±0.25 m occurred with higher (p<0.05) individual variability in V and SL compared to SF. Beta and FD were always in between 1.04 and 1.88 and 1.56 to 1.99, respectively. Beta and FD differed (p<0.05) in SF and SL compared to V and were correlated in V and SL (r=0.91, p<0.05). Spectral peaks of V, SF and SL occurred at wavelengths in between 3 to 35 min, and those of V and SL were interrelated (r=0.56, p<0.05). Mean SF and mean SL were significantly correlated with performance (r=0.59 and r=0.95, p<0.05). SL accounted for 84±6 % and SF for 16±6 % of speed variability, respectively. Conclusions: The observed non-random fluctuations in V, SF and SL correspond to non-stationary fractional Brownian motion with inherent long-range correlations. This indicates a similar complex regulation process in experienced runners that is primarily mediated via SL.

Cortical Brain Activity is Influenced by Cadence in Cyclists

The importance of the central nervous system in endurance exercise has not yet been exhaustively investigated because of difficulties in measuring cortical parameters in sport science. During exercise there are a lot of artifacts and perturbations which can affect signal quality of cortical brain activity. The technical developments of surface electroencephalography (EEG) minimize such influences during standardized test conditions on a bicycle ergometer. The aim of this study was to investigate how movement frequency affects cortical brain activity and established physiological parameters during exercise. In cycling peak performance is affected by cadence. The analysis of brain cortical activity might lead to new insights in the relation of power and cadence. In a laboratory study sixteen male, endurance-trained cyclists completed a 60 min endurance exercise on a high-performance bicycle ergometer. Cadence was changed every 10 min (90-120-60-120-60-90 rpm). EEG was used to analyze changes in cortical brain activity. Furthermore, heart rate, blood lactate and rate of perceived exertion (RPE) were measured after each cadence change. The results indicate that heart rate, blood lactate and RPE were higher at 120 rpm compared to 60 rpm. The spectral EEG power increased statistically significantly in the alpha-2 and beta-2 frequency range by changing cadence from 60 to 120 rpm. By lowering the cadence from 120 to 60 rpm the spectral power dropped statistically significantly in all analyzed EEG frequency bands. The data also showed a statistically significant decrease of spectral EEG power in all frequency ranges over time. In conclusion, the analyzed EEG data indicate that cadence should be considered as an independent exercise normative in the training process, because it directly influences metabolic, cardiac and cortical parameters.

Effects of high intensity training and continuous endurance training on aerobic capacity and body composition in recreationally active runners

The aim of the study was to examine the effects of two different training programs (high-intensity-training vs. continuous endurance training) on aerobic power and body composition in recreationally active men and women and to test whether or not participants were able to complete a half marathon after the intervention period. Thirty-four recreational endurance runners were randomly assigned either to a Weekend-Group (WE, n = 17) or an After-Work- Group (AW, n = 17) for a 12 week-intervention period. WE weekly completed 2 h 30 min of continuous endurance running composed of 2 sessions on the weekend. In contrast, AW performed 4 30 min sessions of high intensity training and an additional 30 min endurance run weekly, always after work. During an exhaustive treadmill test aerobic power was measured and heart rate was continuously recorded. Body composition was assessed using bio-impedance. Following the intervention period all subjects took part in a half-marathon. AW significantly improved peak oxygen uptake (VO2 peak) from 36.8 ± 4.5 to 43.6 ± 6.5 [mL.min(-1).kg(-1)], velocity at lactate threshold (VLT) from 9.7 ± 2.2 to 11.7 ± 1.8 [km.h(-1)] and visceral fat from 5.6 ± 2.2 to 4.7 ± 1.9 In WE VO2 peak signifi-cantly increased from 38.8 ± 5.0 to 41.5 ± 6.0 [mL.min(-1).kg(-1)], VLT from 9.9 ± 1.3 to 11.2 ± 1.7 [km.h(-1)] and visceral fat was reduced from 5.7 ± 2.1 to 5.4 ± 1.9 (p < 0.01). Only the improvements of VO2 peak were significantly greater in AW compared with WE (pre/post group interaction: F=15.4, p = 0.01, η(2) = 0.36). Both groups completed a half marathon with no significant differences in performance (p = 0.63). Short, intensive endurance training sessions of about 30 min are effective in improving aerobic fitness in recreationally active runners. Key pointsContinuous endurance training and high intensity training lead to significant improvements of aerobic capacity and body compositionBoth training methods enable recreationally active runners to finish a half-marathonHigh intensity training is favorable to improve VO2 peak.

A scientific nutrition strategy improves time trial performance by ≈6% when compared with a self-chosen nutrition strategy in trained cyclists: a randomized cross-over study

We investigated whether an athlete’s self-chosen nutrition strategy (A), compared with a scientifically determined one (S), led to an improved endurance performance in a laboratory time trial after an endurance exercise. S consisted of about 1000 mL·h–1 fluid, in portions of 250 mL every 15 min, 0.5 g sodium·L–1, 60 g glucose·h–1, 30 g fructose·h–1, and 5 mg caffeine·kg body mass–1. Eighteen endurance-trained cyclists (16 male; 2 female) were tested using a randomized crossover-design at intervals of 2 weeks, following either A or S. After a warm-up, a maximal oxygen uptake test was performed. Following a 30-min break, a 2.5-h endurance exercise on a bicycle ergometer was carried out at 70% maximal oxygen uptake. After 5 min of rest, a time trial of 64.37 km (40 miles) was completed. The ingested nutrition was recorded every 15 min. In S, the athletes completed the time trial faster (128 vs. 136 min; p ≤ 0.001) and with a significantly higher power output (212 vs. 184 W; p ≤ 0.001). The intake of fluid, energy (carbohydrate-, mono-, and disaccharide), and sodium was significantly higher in S compared with A (p ≤ 0.001) during the endurance exercise. In the time trial, only sodium intake was significantly higher in S (p ≤ 0.001). We concluded that a time trial performance after a 2.5-h endurance exercise in a laboratory setting was significantly improved following a scientific nutrition strategy.

The influence of recovery and training phases on body composition, peripheral vascular function and immune system of professional soccer players

Professional soccer players have a lengthy playing season, throughout which high levels of physical stress are maintained. The following recuperation period, before starting the next pre-season training phase, is generally considered short but sufficient to allow a decrease in these stress levels and therefore a reduction in the propensity for injury or musculoskeletal tissue damage. We hypothesised that these physical extremes influence the body composition, blood flow, and endothelial/immune function, but that the recuperation may be insufficient to allow a reduction of tissue stress damage. Ten professional football players were examined at the end of the playing season, at the end of the season intermission, and after the next pre-season endurance training. Peripheral blood flow and body composition were assessed using venous occlusion plethysmography and DEXA scanning respectively. In addition, selected inflammatory and immune parameters were analysed from blood samples. Following the recuperation period a significant decrease of lean body mass from 74.4+/-4.2 kg to 72.2+/-3.9 kg was observed, but an increase of fat mass from 10.3+/-5.6 kg to 11.1+/-5.4 kg, almost completely reversed the changes seen in the pre-season training phase. Remarkably, both resting and post-ischemic blood flow (7.3+/-3.4 and 26.0+/-6.3 ml/100 ml/min) respectively, were strongly reduced during the playing and training stress phases, but both parameters increased to normal levels (9.0+/-2.7 and 33.9+/-7.6 ml/100 ml/min) during the season intermission. Recovery was also characterized by rising levels of serum creatinine, granulocytes count, total IL-8, serum nitrate, ferritin, and bilirubin. These data suggest a compensated hypo-perfusion of muscle during the playing season, followed by an intramuscular ischemia/reperfusion syndrome during the recovery phase that is associated with muscle protein turnover and inflammatory endothelial reaction, as demonstrated by iNOS and HO-1 activation, as well as IL-8 release. The data provided from this study suggest that the immune system is not able to function fully during periods of high physical stress. The implications of this study are that recuperation should be carefully monitored in athletes who undergo intensive training over extended periods, but that these parameters may also prove useful for determining an individual's risk of tissue stress and possibly their susceptibility to progressive tissue damage or injury.

[Specific riding styles are associated with specific effects on bodily posture control]

BACKGROUND

The assessment of body posture control can be time consuming and cumbersome due to the complexity and the multimodal influence of a multiply influenced system. Various types of equine paces, such as stepping, trotting or galloping, result in acceleration and deceleration forces of different magnitude. These forces induce, in the horseman, reflexes that mediate motor activity to sustain posture balance and counterbalance the gravitational pull. However, there is a paucity of real life data regarding the extent of the various postural subsystems that are recruited to control postural balance in specific equine disciplines, such as classical dressage, show jumping, or vaulting. This study was conducted to bridge that gap.

AIM OF THE STUDY

The aim of this explorative study was to identify the types of the postural subsystems involved in balance control and assess the magnitude of their activities during classical dressage, show jumping, vaulting, and versatility riding.

METHODS

144 horseback riders (8.1 % males) aged 17.3 +/- 2.9 years and 38 age matched controls (non riders) were investigated. The riders studied were competing in dressage, show jumping, vaulting, and versatility. In each individual, postural control was investigated by means of the "interactive balance system (IBS)" that enabled us to determine the spectral power in the following four standard frequency bands: F 1 (0.03 - 0.1 Hz), F 2 - 4 (0.1 - 0.5 Hz), F 5 - 6 (0.5 - 1.0 Hz), and F 7 - 8 (1.0 - 3.0 Hz). In addition, three motorical output indices were calculated: heel-to-toe-ratio (HTR), synchronization of feet (SYNC), and the global stability index of postural balance (STAB). Furthermore, each individual was interviewed regarding riding time, frequency and discipline and also about other sports activities and disorders of health.

RESULTS

The mean training period of the horseback riders was 122 +/- 45.8 months, and mean weekly frequency of training was 5.5 +/- 1.8 days per week. Balance control was most effective in dressage and vaulting riders and least effective in show jumping competitors: HTR was 51 +/- 8 % (dressage), 48 +/- 8 % (show jumping), 47 +/- 8 % (versatility), 51 +/- 7 % (vaulting); SYNC was 523 +/- 124a. i. (dressage), 497 +/- 156a. i. (show jumping), 468 +/- 155a. i. (versatility), 589 +/- 126a. i. (vaulting). Spectral analysis revealed significantly higher power in F 1, F 2 - 4, and F 7 - 8 in dressage competition than in the other equestrian disciplines but not compared with the controls. Significantly differences between riders versus non riders were only found in HTR (p = 0.045) und SYNC (p = 0.009).

CONCLUSIONS

Balance control was most effective in dressage and vaulting riders and least effective in the show jumping competitors. Thus, except for dressage and vaulting, our results do not suggest a positive effect of traditional riding styles on postural stability and control.

The alteration of autonomic function in multiple organ dysfunction syndrome

Autonomic dysfunction is associated with the severity of illness and mortality in patients with multiple organ dysfunction syndrome (MODS) and may contribute significantly to the pathogenesis of this syndrome. Several treatment approaches may possibly restore autonomic function in MODS and thus cause the survival benefit.

Influence of pathologic and simulated visual dysfunctions on the postural system

Visual control has an influence on postural stability. Whilst vestibular, somatosensoric and cerebellar changes have already been frequency analytically parameterized with posturography, sufficient data regarding the visual system are still missing. The aim of this study was to evaluate the influence of pathologic and simulated visual dysfunctions on the postural system by calculating the frequency analytic representation of the visual system throughout the frequency range F1 (0.03-0.1 Hz) of Fourier analysis. The study was divided into two parts. In the first part, visually handicapped subjects and subjects with normal vision were investigated with posturography regarding postural stability (stability effect, Fourier spectrum of postural sway, etc.) with open and closed eyes. The visually impaired and the normal group differed significantly in the frequency range F1 (p = 0.002). Significant differences of the postural stability between both groups were found only in the test position with open eyes (NO). The healthy group showed a significant loss of stability, whereas the impaired group showed an increased stability due to sufficient somatosensoric processes. Visually handicapped persons can compensate the visual information deficit through improved peripheral-vestibular and somatosensoric perception and cerebellar processing. In the second part, subjects with normal vision were examined under simulated visual conditions, e.g., hyperopia (3.0 D), reduced visual acuity (VA = 20/200), yoke prisms (4 cm/m) and pursuits (pendulum). Changes in postural parameters due to simulations have been compared to a standard situation (open eyes [NO], fixation distance 3 m). Visual simulations showed influence on frequency range F1. Compared to the standard situation, significant differences have been found in reduced visual acuity, pursuits and yoke prisms. A loss of stability was measured for simulated hyperopia, pendulum and yoke prisms base down. Stability regulation can be understood as a multi-sensoric process by the visual, vestibular, somatosensoric and cerebellar system. Reduced influence of a single subsystem is compensated by the other subsystems. Obviously the main part of reduced visual input is compensated by the vestibular system. Moreover, the body sway, represented by the stability indicator, increased in this situation.

[Heart rate variability and physical exercise. Current status]

Heart rate variability (HRV) has long been used in risk stratification for sudden cardiac death and diabetic autonomic neuropathy. In recent years, both time and frequency domain indices of HRV also gained increasing interest in sports and training sciences. In these fields, HRV is currently used for the noninvasive assessment of autonomic changes associated with short-term and long-term endurance exercise training in both leisure sports activity and high-performance training. Furthermore, HRV is being investigated as a diagnostic marker of overreaching and overtraining.A large body of evidence shows that, in healthy subjects and cardiovascular patients of all ages (up to an age of 70 years), regular aerobic training usually results in a significant improvement of overall as well as instantaneous HRV. These changes, which are accompanied by significant reductions in heart rates both at rest and during submaximal exercise, reflect an increase in autonomic efferent activity and a shift in favor of enhanced vagal modulation of the cardiac rhythm. Regular aerobic training of moderate volume and intensity over a minimum period of 3 months seems to be necessary to ensure these effects, which might be associated with a prognostic benefit regarding overall mortality.At present, available data does not allow for final conclusions with respect to the usefulness of traditional HRV indices in assessing an individual's exercise performance and monitoring training load. The discrepant results published so far are due to several factors including insufficient study size and design, and different HRV methods. Large-sized and prospectively designed studies are necessary for clarification. It also remains to be seen, whether the traditional HRV indices prove useful in the diagnosis of overreaching and overtraining. Preliminary results, though promising, need to be confirmed in larger cohorts.A basic problem in HRV analysis is nonstationarity of the heart rate signal, which holds particularly true for exercise conditions. Whether, in these conditions, more robust nonlinear HRV methods offer a benefit has to be established in further work.

Syncope due to Brugada syndrome in a young athlete

A 30-year-old male athlete with exercise-related syncopal symptoms spontaneously exhibited a type 1 Brugada ECG and was inducible during electrophysiology study. He was diagnosed with symptomatic Brugada syndrome and deemed at high risk of sudden cardiac death. Thus, he received a cardioverter/defibrillator and was advised to abstain from further competitive sports activities. This case points to a role of the ECG in pre-participation screening. It also demonstrates that, in athletes with Brugada syndrome, repolarisation anomalies may be markedly attenuated during vigorous exercise and considerably increased immediately after exercise. The observed J-wave amplitude dynamics suggests enhancement of pre-existing autonomic dysfunction through heavy exertion.

Flow-Erleben unter kontrollierter Beanspruchungssteuerung

Zusammenfassung. Sportliche Aktivitäten wurden von Anbeginn in die Flow-Forschung einbezogen, wobei recht bald deutlich wurde, dass eine verlaufsnahe Diagnostik, also einer Diagnostik während der sportlichen Tätigkeit, dem Flow-Konstrukt am Besten entspricht. Allerdings liefern Feldstudien, welche die Auslösebedingungen für das Auftreten von Flow und die Flow-Leistungsbeziehung bei sportlichen Aktivitäten zu klären versuchen, eher inkonsistente Befunde. Ziel der vorliegenden Laufbandstudie war es daher: 1) zu prüfen, ob die von Csikszentmihalyi (1975) postulierte Anforderungs-Fähigkeits-Passung für Läufer auch unter Laborbedingungen Voraussetzung für das Auftreten von Flow ist und 2) die Dynamik des Flow-Erlebens im Zeitverlauf und in Abhängigkeit physiologischer Leistungsparameter beim Laufen zu dokumentieren. Mit Hilfe einer beanspruchungsorientierten Geschwindigkeitssteuerung des Laufbands gelang es, die Probanden (N = 30) auf einem individuell bestimmten, überdurchschnittlichem Anspruchsniveau kontrolliert 40 Minuten laufen zu lassen. Im Fazit lässt sich feststellen, dass die Probanden über ein tiefes und im Verlauf stabiles Flow-Erleben berichten. Allerdings ist dies davon unabhängig, ob sie subjektiv eine optimale Anforderungs-Fähigkeits-Passung erleben.

[Aspergillus infections of the lung]

In this article the three different manifestations of pulmonary aspergillosis are compared with each other: bronchopulmonary aspergillosis, aspergilloma and invasive pulmonary aspergillosis, and their different clinical and radiological manifestations. In particular, invasive pulmonary aspergillosis--being a severe complication in immunosuppressed patients whose defenses are weak--often presents diagnostic problems due to its initially mostly unspecific clinical and radiological signs. The late signs of a pulmonary aspergillus infection, such as formation of a cavern or the manifestation of the "air crescent" sign, however, are seen only when the patient is just beginning to convalesce.