983 research outputs found
A Fluid Shift for Endurance Exercise - Why Hydration Matters
No full textAs modern-day humans, we still bear the genetic heritage of our ancestors who evolved under conditions very different from today and who were selected for a great amount of daily physical exercise.1 We should be aware of this two-million-year-old heritage 2 and include physical exercise in our everyday lives to prevent civilization-induced disorders, as for example metabolic syndrome and cardiovascular diseases,3 and to stay physically and mentally fit.4 Indeed, regular endurance training has many beneficial consequences such as improved cardiovascular function, lower morbidity, and mortality rates and overall improved physical fitness.5-7 Moreover, exercise training may even reverse pathological changes associated with diseases of civilization
Mauersegler weiter Wege. Mathias Enard: Kompass
No full textAnalysis of the peculiar scientific narrative in the novel of the Prix-Goncourt winning author Mathias Enard
Les commissions électorales en Afrique de l'Ouest
No full text[author: Mathias Hounkpe ; Ismaila Madior Fall]Electronic ed.: Abuja ; Bonn : FES, 201
The Advantage of Supine and Standing Heart Rate Variability Analysis to Assess Training Status and Performance in a Walking Ultramarathon
Full text linkCardiac autonomic modulation of heart rate, assessed by heart rate variability (HRV), is commonly used to monitor training status. HRV is usually measured in athletes after awakening in the morning in the supine position. Whether recording during standing reveals additional information compared to supine remains unclear. We aimed to evaluate the association between short-duration HRV, assessed both in the supine and standing position, and a low-intensity long-duration performance (walking ultramarathon), as well as training experience. Twenty-five competitors in a 100 km walking ultramarathon underwent pre-race supine (12 min) and standing (6 min) HR recordings, whereas performance and subjective training experience were assessed post-race. There were no significant differences in both supine and standing HRV between finishers (n = 14) and non-finishers (n = 11, mean distance 67 km). In finishers, a slower race velocity was significantly correlated with a higher decrease in parasympathetic drive during position change [larger decrease in High Frequency power normalized units (HFnu: r = −0.7, p = 0.01) and higher increase in the detrended fluctuation analysis alpha 1 index (DFA1: r = 0.6, p = 0.04)]. Highly trained athletes accounted for higher HFnu during standing compared to poorly trained competitors (+11.5, p = 0.01). Similarly, greater training volume (total km/week) would predict higher HFnu during standing (r = 0.5, p = 0.01). HRV assessment in both supine and standing position may provide additional information on the dynamic adaptability of cardiac autonomic modulation to physiologic challenges and therefore be more valuable for performance prediction than a simple assessment of supine HRV. Self-reported training experience may reliably associate with parasympathetic drive, therefore indirectly predicting long-term aerobic performance in ultramarathon walking races
Physiological Changes during an Ultramarathon in Extreme Cold: The Yukon Arctic Ultra, the Longest and Coldest Ultramarathon
Full text linkAn increasing number of people engage in endurance exercise, however, current literature lacks information regarding changes during ultramarathons of very long distances at very low intensity, i.e., walking instead of running. In addition, adverse conditions, like very cold climate, have not been investigated in such settings. Furthermore, the physiological processes linking functions like energy expenditure, metabolism, stress, and resilience, are still not well understood or lack investigation all together.
The Yukon Arctic Ultra (YAU) has been coined to be the longest and the coldest ultramarathon in the world, as it challenges athletes to complete the very long distance of 690 km under the extremely cold climate conditions of North-Canadian subarctic winter. YAU athletes face the challenges of long-term endurance exercise in a very cold climate and under diminished resting conditions. Thusly, the YAU served as a model to investigate physiological changes among healthy athletes during an ultra-long endurance exercise in extremely cold climate.
The presented investigation revealed considerable increases in energy expenditure among the athletes, of up to more than four times resting metabolic rate, along with a marked energy deficit, changes in body composition with reductions in fat mass while fat free mass could mostly be retained, possibly to the exercise- and cold-induced release of myokines like irisin and follistatin.
Furthermore, analysis of vegetative control expressed through heart rate variability, as well as of mood through psychometric measurements, revealed that the more successful athletes, who would eventually be able to finish the race, showed better adaptation to the race demands, with less depression, anxiety and anger, but greater vigor and higher alertness. They also exhibited a faster restoration of vagal predominance during the race with a better ability to relax and restore, leading to less sleepiness and greater vigilance compared to the non-finishing athletes.
Resilience, as the ability to cope with stressful events, appears to be a key element during such a race and neuropeptide Y has been discussed as a mediator in resilience reactions. The analyses revealed that during this race, neuropeptide Y was associated with less confusion and better quality of recovery among the finisher group and that overall neuropeptide Y was increasingly released among the athletes compared to the less challenged control group.
Another influence was the factor sex, indicating that the female athletes were not only as successful as the male participants to complete the whole race, but that women completed an overall greater distance, when accounting for all covered distances. Women, with a moving speed of 3.7 km/h, were considerably slower than men at 4.6 km/h, which may have saved energy stores and allowed them to predominantly use fat as a long-term energy source.
In addition, it was shown that ultra-long endurance exercise may lead to shedding of endothelial glycocalyx elements and that these elements appear to be differently susceptible to that shedding. Sex, age, and covered distance all appeared to have an influence on the observed changes.
The analyses of physiological changes during the Yukon Arctic Ultra have revealed a multitude of endurance- and cold-exposure-related alterations. This ultramarathon has thusly proven to be an outstanding model to study human adaptation capabilities to extreme environments under real-life field conditions that could otherwise not be replicated in a laboratory setting
Physiological long term changes in overwinterers in the Antarctic with particular consideration of activity parameters
No full textAufenthalte des Menschen in Extremen Umwelten wie der Antarktis sowie in
anderen isolierten und beengten Umgebungen können als Analog für Aufenthalte
des Menschen im Weltraum dienen. Ziel der vorgelegten Arbeit war es vor diesem
Hintergrund, die Langzeitveränderungen bei Teilnehmern von vier
Überwinterungsstaffeln in der Antarktis hinsichtlich der
Körperzusammensetzung, des Schlafes und des Energieumsatzes sowie
verschiedener Hormon- und Stoffwechselparameter zu untersuchen.Residence of humans in extreme environments such as the Antarctic as well as
in other isolated and confined environments can be used as an analog for the
stay of humans in outer space. Therefore it was the purpose of this thesis to
investigate the long term changes in participants of four overwintering
campaigns in the Antarctic regarding body composition, sleep, energy
expenditure and various hormonal and metabolic parameters
Physiologische Langzeitveränderungen bei Überwinterern in der Antarktis unter besonderer Berücksichtigung von Aktivitätsparametern
No full textPaul Bourget, écrivain engagé
No full textPaul Bourget, A committed writer, Yehoshua Mathias.
In the France of the early twentieth century, Paul Bourget's figure is that of a successful novelist who became gradually a «committed author». A monarchist, deeply conservative, passionate defender of religion and the family as the vital bases of the social order, he thus became the bard of the bourgeois ethic faced with the destabilization of modernity.Mathias Yehoshua. Paul Bourget, écrivain engagé. In: Vingtième Siècle, revue d'histoire, n°45, janvier-mars 1995. pp. 14-29
„Nature must be felt“ – Alexander von Humboldt, pioneer of an ecological worldview and protagonist of „transversal reason“
No full textDer Text erinnert zum 250sten Geburtsjahr an Alexander von Humboldt, ein Vordenker für eine ökologische Sicht der Welt und ein früher Protagonist „transversaler Vernunft“. Er ist als Ideengeber für die „neuen Naturtherapien“, für die Integrative Therapie und für eine ökologische Sicht in der Psychotherapie eine unverzichtbare Quelle. Einige aus dieser Perspektive wichtige Aspekte seines Denkens und Werkes werden aufgezeigt. Er ist ein Referenzautor für transversales und integratives Konzeptualisieren in unserer Zeit.The text commemorates the 250th year of birth of Alexander von Humboldt, a thought leader for an ecological view of the world and an early protagonist of „transversal reason“. He is an indispensable source of ideas for the „new nature therapies“, for integrative therapy and for an ecological viewpoint in psychotherapy. Some important aspects of his thinking and work are shown from this perspective. He is a reference author for transversal and integrative conceptualization in our time.https://www.fpi-publikation.de/gruene-texte/17-2019-petzold-h-g-mathias-wiedemann-u-natur-muss-gefuehlt-werden-alexander-v-humboldt/peerReviewedpublishedVersio
Cardiac Autonomic Modulations and Psychological Correlates in the Yukon Arctic Ultra: The Longest and the Coldest Ultramarathon
Full text linkStudies on human physical performance in extreme environments have effectively approached the investigation of adaptation mechanisms and their physiological limits. As scientific interest in the interplay between physiological and psychological aspects of performance is growing, we aimed to investigate cardiac autonomic control, by means of heart rate variability, and psychological correlates, in competitors of a subarctic ultramarathon, taking place over a 690 km course (temperatures between +5 and −47°C). At baseline (PRE), after 277 km (D1), 383 km (D2), and post-race (POST, 690 km), heart rate (HR) recordings (supine, 15 min), psychometric measurements (Profile of Mood States/POMS, Borg fatigue, and Karolinska Sleepiness Scale scores both upon arrival and departure) were obtained in 16 competitors (12 men, 4 women, 38.6 ± 9.5 years). As not all participants reached the finish line, comparison of finishers (FIN, n = 10) and non-finishers (NON, n = 6), allowed differential assessment of performance. Resting HR increased overall significantly at D1 (FIN +15.9; NON +14.0 bpm), due to a significant decrease in parasympathetic drive. This decrease was in FIN only partially recovered toward POST. In FIN only, baseline HR was negatively correlated with mean velocity [r −0.63 (P.04)] and parasympathetic drive [pNN50+: r −0.67 (P.03)], a lower HR and a higher vagal tone predicting a better performance. Moreover, in FIN, a persistent increase of the long-term self-similarity coefficient, assessed by detrended fluctuation analysis (DFAα2), was retrieved, possibly due to higher alertness. As for psychometrics, at D1, POMS Vigor decreased (FIN: −7.0; NON: −3.8), while Fatigue augmented (FIN: +6.9; NON: +5.0). Sleepiness increased only in NON, while Borg scales did not exhibit changes. Baseline comparison of mood states with normative data for athletes displayed significantly higher positive mood in our athletes. Results show that: the race conditions induced early decreases in parasympathetic drive; the extent of vagal withdrawal, associated to the timing of its recovery, is crucial for success; pre-competition lower resting HR predicts a better performance; psychological profile is reliably depicted by POMS, but not by Borg fatigue scales. Therefore, assessment of heart rate variability and psychological profile may monitor and partly predict performance in long-duration ultramarathon in extreme cold environment
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