{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,28]],"date-time":"2026-09-28T22:31:09Z","timestamp":1790634669071,"version":"4.1.0"},"reference-count":92,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2021,3,11]],"date-time":"2021-03-11T00:00:00Z","timestamp":1615420800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Physiol."],"abstract":"<jats:sec><jats:title>Background<\/jats:title><jats:p>Long-endurance exercises like ultramarathons are known to elicit various metabolic and physiological changes in the human body. However, little is known about very long-duration exercise at low intensities regarding healthy human subjects.<\/jats:p><\/jats:sec><jats:sec><jats:title>Aim<\/jats:title><jats:p>The purpose of this study was to evaluate changes in body composition and metabolism in long-endurance but low-intensity events.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>Twenty-five male and 18 female healthy recreational athletes (age 34.6 \u00b1 8.8 years; BMI: 22.4 \u00b1 2.0 kg\/m<jats:sup>2<\/jats:sup>) of the \u201c100 km Mammutmarsch\u201d were recruited for participation during the events in 2014\u20132016. Other than classical ultramarathons, the \u201cMammutmarsch\u201d is a hiking event, in which participants were required to walk but not run or jog. It was expected to complete the 100-km distance within 24 h, resulting in a calculated mean speed of 4.17 km\/h, which fits to the mean speed observed (4.12 \u00b1 0.76 km\/h). As not all participants reached the finish line, comparison of finishers (FIN, <jats:italic>n<\/jats:italic> = 11) and non-finishers (NON, <jats:italic>n<\/jats:italic> = 21) allowed differential assessment of performance. Body composition measured through bioelectrical impedance analysis (BIA) was determined pre- and post-event, and serum samples were taken pre-event, at 30, 70, and 100 km to determine NT-pro-BNP, troponin T, C-reactive protein (CRP), cortisol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglycerides, total cholesterol, total creatine kinase (CK), CK-MB, aminotransferase (AST), ALT, and sodium levels. Nineteen participants wore actimeter armbands (SenseWear<jats:sup>\u00ae<\/jats:sup>) to gain information about body activity and exercise intensity [metabolic equivalent of task (MET)]. Sixteen participants wore mobile heart rate monitors to assess mean heart rate during the race. Serum parameter alterations over the course of the race were analyzed with mixed-effects ANOVA and additional <jats:italic>t<\/jats:italic>-tests. All serum parameters were analyzed for correlation concerning different MET levels, speed, age, BMI, baseline NT-pro-BNP, mean heart rate during the race, and sex with linear regression analysis.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>We found significant elevations for muscle and cardiac stress markers (CRP, CK, CK-MB, AST, ALT, cortisol, and NT-pro-BNP) as well as decreasing markers of lipid metabolism (cholesterol, triglycerides, LDL). Although the intensity level demanded from our participants was low compared with other studies on (ultra-) marathons, the alteration of tested parameters was similar to those of high-intensity exercise, e.g., NT-pro-BNP showed a fourfold increase (<jats:italic>p<\/jats:italic> &amp;lt; 0.01) and LDL decreased by 20% (<jats:italic>p<\/jats:italic> = 0.05). Besides the duration of exercise, age, BMI, training status, and sex are relevant parameters that influence the elevation of stress factors. Notably, our data indicate that NT-pro-BNP might be a marker for cardiovascular fitness also in healthy adults.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>This low-intensity long-endurance walk evoked a strong systemic reaction and large cell stress and shifted to a favorable lipid profile, comparable to higher intensity events. Despite increasing cardiac stress parameters, there were no indications of cardiac cell damage. Remarkably, the duration seems to have a greater influence on stress markers and metabolism than intensity.<\/jats:p><\/jats:sec>","DOI":"10.3389\/fphys.2021.640710","type":"journal-article","created":{"date-parts":[[2021,3,11]],"date-time":"2021-03-11T07:40:57Z","timestamp":1615448457000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":14,"title":["Physiological Changes, Activity, and Stress During a 100-km\u201324-h Walking-March"],"prefix":"10.3389","volume":"12","author":[{"given":"Marc","family":"J\u00f6rres","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hanns-Christian","family":"Gunga","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mathias","family":"Steinach","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2021,3,11]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"369","DOI":"10.1007\/s10654-006-9100-3","article-title":"Associations between overall physical activity level and cardiovascular risk factors in an adult population.","volume":"22","author":"Aadahl","year":"2007","journal-title":"Eur. J. Epidemiol."},{"key":"B2","doi-asserted-by":"publisher","first-page":"92","DOI":"10.1097\/00005768-200201000-00015","article-title":"Determination of the exercise intensity that elicits maximal fat oxidation.","volume":"34","author":"Achten","year":"2002","journal-title":"Med. Sci. Sports Exerc."},{"key":"B3","doi-asserted-by":"publisher","first-page":"71","DOI":"10.1249\/00005768-199301000-00011","article-title":"Compendium of physical activities: classification of energy costs of human physical activities.","volume":"25","author":"Ainsworth","year":"1993","journal-title":"Med. Sci. Sports Exerc."},{"key":"B4","doi-asserted-by":"publisher","first-page":"337","DOI":"10.1016\/bs.pmbts.2015.07.003","article-title":"Exercise and the regulation of inflammatory responses.","volume":"135","author":"Allen","year":"2015","journal-title":"Prog. Mol. Biol. Transl. Sci."},{"key":"B5","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1016\/j.jtbi.2004.08.029","article-title":"A limit on the energy transfer rate from the human fat store in hypophagia.","volume":"233","author":"Alpert","year":"2005","journal-title":"J. Theor. Biol."},{"key":"B6","doi-asserted-by":"publisher","first-page":"365","DOI":"10.1080\/02701367.2011.10599766","article-title":"How much walking is needed to improve cardiorespiratory fitness? An examination of the 2008 Physical Activity Guidelines for Americans.","volume":"82","author":"Anton","year":"2011","journal-title":"Res. Q. Exerc. Sport"},{"key":"B7","doi-asserted-by":"publisher","first-page":"456","DOI":"10.1177\/1099800413505900","article-title":"Quench the thirst: lessons from clinical thirst trials.","volume":"16","author":"Arai","year":"2014","journal-title":"Biol. Res. Nurs."},{"key":"B8","doi-asserted-by":"publisher","first-page":"43","DOI":"10.2147\/OAJSM.S97468","article-title":"Changes in blood biochemical markers before, during, and after a 2-day ultramarathon.","volume":"7","author":"Arakawa","year":"2016","journal-title":"Open Access J. Sports Med."},{"key":"B9","doi-asserted-by":"publisher","first-page":"233","DOI":"10.1016\/j.arteri.2019.04.004","article-title":"Sedentary lifestyle a disease from xxi century.","volume":"31","author":"Arocha Rodulfo","year":"2019","journal-title":"Clin. Investig. Arterioscler."},{"key":"B10","doi-asserted-by":"publisher","DOI":"10.1155\/2012\/960363","article-title":"Creatine-kinase- and exercise-related muscle damage implications for muscle performance and recovery.","volume":"2012","author":"Baird","year":"2012","journal-title":"J. Nutr. Metab."},{"key":"B11","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1016\/b978-0-12-394317-0.00015-7","article-title":"Metabolic markers in sports medicine.","volume":"56","author":"Banfi","year":"2012","journal-title":"Adv. Clin. Chem."},{"key":"B12","doi-asserted-by":"publisher","first-page":"70","DOI":"10.1097\/00005768-200001000-00012","article-title":"Limiting factors for maximum oxygen uptake and determinants of endurance performance.","volume":"32","author":"Bassett","year":"2000","journal-title":"Med. Sci. Sports Exerc."},{"key":"B13","doi-asserted-by":"publisher","first-page":"447","DOI":"10.1007\/s00421-015-3291-9","article-title":"Fluid retention, muscle damage, and altered body composition at the Ultraman triathlon.","volume":"116","author":"Baur","year":"2016","journal-title":"Eur. J. Appl. Physiol."},{"key":"B14","doi-asserted-by":"publisher","first-page":"1252","DOI":"10.1177\/2047487316631389","article-title":"Impact of prolonged walking exercise on cardiac structure and function in cardiac patients versus healthy controls.","volume":"23","author":"Benda","year":"2016","journal-title":"Eur. J. Prev. Cardiol."},{"key":"B15","doi-asserted-by":"publisher","first-page":"960","DOI":"10.3389\/fpsyg.2016.01680","article-title":"Gender differences in the accuracy of self-evaluations of performance.","volume":"59","author":"Beyer","year":"1990","journal-title":"J. Pers. Soc. Psychol."},{"key":"B16","doi-asserted-by":"publisher","DOI":"10.3389\/fphys.2019.01550","article-title":"Inflammatory effects of high and moderate intensity exercise-a systematic review.","volume":"10","author":"Cerqueira","year":"2020","journal-title":"Front. Physiol."},{"key":"B18","doi-asserted-by":"publisher","first-page":"357","DOI":"10.1249\/MSS.0000000000001095","article-title":"Metabolic responses to the yukon arctic ultra: longest and coldest in the world.","volume":"49","author":"Coker","year":"2017","journal-title":"Med. Sci. Sports Exerc."},{"key":"B19","doi-asserted-by":"publisher","first-page":"1710","DOI":"10.1016\/s0195-668x(03)00476-7","article-title":"Clinical applications of B-type natriuretic peptide (BNP) testing.","volume":"24","author":"Cowie","year":"2003","journal-title":"Eur. Heart J."},{"key":"B20","doi-asserted-by":"publisher","first-page":"165","DOI":"10.1152\/jappl.1986.61.1.165","article-title":"Muscle glycogen utilization during prolonged strenuous exercise when fed carbohydrate.","volume":"61","author":"Coyle","year":"1986","journal-title":"J. Appl. Physiol."},{"key":"B21","doi-asserted-by":"publisher","first-page":"1100","DOI":"10.1093\/oxfordjournals.aje.a008686","article-title":"Sex difference in high density lipoprotein cholesterol in six countries.","volume":"143","author":"Davis","year":"1996","journal-title":"Am. J. Epidemiol."},{"key":"B22","year":"2020"},{"key":"B23","doi-asserted-by":"publisher","first-page":"249","DOI":"10.1080\/00913847.2019.1568769","article-title":"Asymptomatic bradycardia amongst endurance athletes.","volume":"47","author":"Doyen","year":"2019","journal-title":"Phys. Sportsmed."},{"key":"B24","doi-asserted-by":"publisher","first-page":"2093","DOI":"10.1016\/s0024-3205(01)00996-1","article-title":"Exploration of the awakenin\/g cortisol response in relation to diurnal cortisol secretory activity.","volume":"68","author":"Edwards","year":"2001","journal-title":"Life Sci."},{"key":"B25","doi-asserted-by":"publisher","first-page":"267","DOI":"10.1016\/j.amjcard.2009.08.679","article-title":"Effect of prolonged walking on cardiac troponin levels.","volume":"105","author":"Eijsvogels","year":"2010","journal-title":"Am. J. Cardiol."},{"key":"B26","doi-asserted-by":"publisher","first-page":"1701","DOI":"10.1016\/j.jacc.2017.08.016","article-title":"Exercise for coronary heart disease patients: little is good, more is better, vigorous is best.","volume":"70","author":"Eijsvogels","year":"2017","journal-title":"J. Am. Coll. Cardiol."},{"key":"B27","doi-asserted-by":"publisher","first-page":"1657","DOI":"10.1080\/02640414.2015.1130237","article-title":"Acute modification in plasma lipid levels in ultramarathon runners.","volume":"34","author":"Emed","year":"2016","journal-title":"J. Sports Sci."},{"key":"B28","doi-asserted-by":"publisher","first-page":"38","DOI":"10.1097\/00042752-200101000-00007","article-title":"The acute phase response and exercise: the ultramarathon as prototype exercise.","volume":"11","author":"Fallon","year":"2001","journal-title":"Clin. J. Sport Med."},{"key":"B29","doi-asserted-by":"publisher","first-page":"9","DOI":"10.1016\/j.vph.2017.11.005","article-title":"Effects of endurance training on serum lipids.","volume":"101","author":"Fikenzer","year":"2018","journal-title":"Vascul. Pharmacol."},{"key":"B30","doi-asserted-by":"crossref","first-page":"221","DOI":"10.1001\/jama.1996.03540030055032","article-title":"Effects of a single bout of ultraendurance exercise on lipid levels and susceptibility of lipids to peroxidation in triathletes.","volume":"276","author":"Ginsburg","year":"1996","journal-title":"JAMA"},{"key":"B31","doi-asserted-by":"publisher","first-page":"776","DOI":"10.1016\/S0140-6736(16)30175-1","article-title":"Body-mass index and all-cause mortality: individual-participant-data meta-analysis of 239 prospective studies in four continents.","volume":"388","author":"Di Angelantonio","year":"2016","journal-title":"Lancet"},{"key":"B32","year":"2020"},{"key":"B33","doi-asserted-by":"publisher","first-page":"1257","DOI":"10.1016\/j.medengphy.2008.06.009","article-title":"Body fluid volumes measurements by impedance: a review of bioimpedance spectroscopy (BIS) and bioimpedance analysis (BIA) methods.","volume":"30","author":"Jaffrin","year":"2008","journal-title":"Med. Eng. Phys."},{"key":"B34","doi-asserted-by":"publisher","first-page":"274","DOI":"10.1111\/j.1600-0838.1997.tb00152.x","article-title":"Pronounced resting bradycardia in male elite runners is associated with high heart rate variability.","volume":"7","author":"Jensen-Urstad","year":"1997","journal-title":"Scand. J. Med. Sci. Sports"},{"key":"B35","doi-asserted-by":"publisher","first-page":"27","DOI":"10.1016\/j.jesf.2017.06.001","article-title":"Association between resting heart rate, metabolic syndrome and cardiorespiratory fitness in Korean male adults.","volume":"15","author":"Kang","year":"2017","journal-title":"J. Exerc. Sci. Fit."},{"key":"B36","doi-asserted-by":"publisher","first-page":"1489","DOI":"10.1016\/0002-8703(87)90666-1","article-title":"Heart rate and cardiovascular mortality: the Framingham Study.","volume":"113","author":"Kannel","year":"1987","journal-title":"Am. Heart J."},{"key":"B37","first-page":"533","article-title":"Running a 100-km ultra-marathon induces an inflammatory response but does not raise the level of the plasma iron-regulatory protein hepcidin.","volume":"53","author":"Kasprowicz","year":"2013","journal-title":"J. Sports Med. Phys. Fitness"},{"key":"B38","first-page":"272","article-title":"Rhabdomyolysis: a review of the literature.","volume":"67","author":"Khan","year":"2009","journal-title":"Neth. J. Med."},{"key":"B39","doi-asserted-by":"publisher","DOI":"10.3390\/ijerph15071378","article-title":"High body mass index is associated with the extent of muscle damage after eccentric exercise.","volume":"15","author":"Kim","year":"2018","journal-title":"Int. J. Environ. Res. Public Health"},{"key":"B40","doi-asserted-by":"publisher","first-page":"S92","DOI":"10.1080\/17461391.2011.654267","article-title":"The effects of running a 308 km ultra-marathon on cardiac markers.","volume":"14","author":"Kim","year":"2014","journal-title":"Eur. J. Sport Sci."},{"key":"B41","doi-asserted-by":"publisher","first-page":"2781","DOI":"10.1007\/s00421-013-2714-8","article-title":"Metabolic responses to a 48-h ultra-marathon run in middle-aged male amateur runners.","volume":"113","author":"K\u0142apci\u0144ska","year":"2013","journal-title":"Eur. J. Appl. Physiol."},{"key":"B42","doi-asserted-by":"publisher","DOI":"10.3389\/fphys.2018.00634","article-title":"Physiology and pathophysiology in ultra-marathon running.","volume":"9","author":"Knechtle","year":"2018","journal-title":"Front. Physiol."},{"key":"B43","doi-asserted-by":"publisher","first-page":"121","DOI":"10.1136\/bjsm.2007.038034","article-title":"Effect of a multistage ultra-endurance triathlon on body composition: World Challenge Deca Iron Triathlon 2006.","volume":"42","author":"Knechtle","year":"","journal-title":"Br. J. Sports Med."},{"key":"B44","doi-asserted-by":"publisher","DOI":"10.3390\/ijerph17051719","article-title":"Participation and performance trends in the oldest 100-km Ultramarathon in the World.","volume":"17","author":"Knechtle","year":"2020","journal-title":"Int. J. Environ. Res. Public Health"},{"key":"B45","doi-asserted-by":"publisher","first-page":"609","DOI":"10.1136\/bjsm.2007.040956","article-title":"Decrease in body fat during an ultra-endurance triathlon is associated with race intensity.","volume":"42","author":"Knechtle","year":"","journal-title":"Br. J. Sports Med."},{"key":"B46","doi-asserted-by":"publisher","DOI":"10.1007\/s11357-014-9715-3","article-title":"What is the age for the fastest ultra-marathon performance in time-limited races from 6 h to 10 days?","volume":"36","author":"Knechtle","year":"2014","journal-title":"Age"},{"key":"B47","doi-asserted-by":"publisher","DOI":"10.1001\/jama.282.19.1816","article-title":"Regular exercise and subclinical myocardial injury during prolonged aerobic exercise.","volume":"282","author":"Koller","year":"1999","journal-title":"JAMA"},{"key":"B48","doi-asserted-by":"publisher","DOI":"10.1016\/j.healthplace.2020.102447","article-title":"Built environment correlates of objectively-measured sedentary behaviours in densely-populated areas.","volume":"66","author":"Koohsari","year":"2020","journal-title":"Health Place"},{"key":"B49","doi-asserted-by":"publisher","first-page":"860","DOI":"10.1136\/hrt.2006.101063","article-title":"Biochemical and functional abnormalities of left and right ventricular function after ultra-endurance exercise.","volume":"94","author":"La Gerche","year":"2008","journal-title":"Heart"},{"key":"B51","doi-asserted-by":"publisher","first-page":"109","DOI":"10.1159\/000447370","article-title":"Perspiration functions in different ethnic, age, and sex populations: modification of Sudomotor function.","volume":"51","author":"Lee","year":"2016","journal-title":"Curr. Probl. Dermatol."},{"key":"B52","doi-asserted-by":"publisher","first-page":"2961","DOI":"10.1007\/s00421-011-1922-3","article-title":"The impact of exercise intensity on the release of cardiac biomarkers in marathon runners.","volume":"111","author":"Legaz-Arrese","year":"2011","journal-title":"Eur. J. Appl. Physiol."},{"key":"B53","doi-asserted-by":"publisher","DOI":"10.1186\/s12966-020-01055-x","article-title":"Workplace neighbourhood built environment and workers\u2019 physically-active and sedentary behaviour: a systematic review of observational studies.","volume":"17","author":"Lin","year":"2020","journal-title":"Int. J. Behav. Nutr. Phys. Act."},{"key":"B54","first-page":"1163","article-title":"Estimation of body fluid volumes using tetrapolar bioelectrical impedance measurements.","volume":"59","author":"Lukaski","year":"1988","journal-title":"Aviat. Space Environ. Med."},{"key":"B55","doi-asserted-by":"publisher","first-page":"161","DOI":"10.1056\/NEJMoa020233","article-title":"Rapid measurement of B-type natriuretic peptide in the emergency diagnosis of heart failure.","volume":"347","author":"Maisel","year":"2002","journal-title":"N. Engl. J. Med."},{"key":"B56","year":"2018"},{"key":"B57","doi-asserted-by":"publisher","first-page":"211","DOI":"10.1007\/s40279-013-0110-5","article-title":"Differential effects of aerobic exercise, resistance training and combined exercise modalities on cholesterol and the lipid profile: review, synthesis and recommendations.","volume":"44","author":"Mann","year":"2014","journal-title":"Sports Med."},{"key":"B58","doi-asserted-by":"publisher","first-page":"66","DOI":"10.1152\/japplphysiol.01538.2011","article-title":"Extensive inflammatory cell infiltration in human skeletal muscle in response to an ultraendurance exercise bout in experienced athletes.","volume":"114","author":"Marklund","year":"2013","journal-title":"J. Appl. Physiol."},{"key":"B59","doi-asserted-by":"publisher","DOI":"10.3389\/fphys.2020.00731","article-title":"The advantage of supine and standing heart rate variability analysis to assess training status and performance in a walking ultramarathon.","volume":"11","author":"Maggioni","year":"2020","journal-title":"Front. Physiol."},{"key":"B60","doi-asserted-by":"publisher","first-page":"170","DOI":"10.1007\/s11892-001-0030-x","article-title":"Obesity and sedentary lifestyle: modifiable risk factors for prevention of type 2 diabetes.","volume":"1","author":"Mayer-Davis","year":"2001","journal-title":"Curr. Diab. Rep."},{"key":"B61","doi-asserted-by":"publisher","first-page":"333","DOI":"10.1055\/s-0031-1301322","article-title":"Post-exercise cardiac troponin release is related to exercise training history.","volume":"33","author":"Mehta","year":"2012","journal-title":"Int. J. Sports Med."},{"key":"B62","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0200701","article-title":"Metabolic equivalent of task (METs) thresholds as an indicator of physical activity intensity.","volume":"13","author":"Mendes","year":"2018","journal-title":"PLoS One"},{"key":"B63","doi-asserted-by":"publisher","first-page":"1280","DOI":"10.1172\/JCI118162","article-title":"Rapid transcriptional activation and early mRNA turnover of brain natriuretic peptide in cardiocyte hypertrophy. Evidence for brain natriuretic peptide as an \u201cemergency\u201d cardiac hormone against ventricular overload.","volume":"96","author":"Nakagawa","year":"1995","journal-title":"J. Clin. Invest."},{"key":"B64","doi-asserted-by":"publisher","first-page":"73","DOI":"10.1016\/j.amjmed.2008.08.033","article-title":"Relationship of ethnic origin, gender, and age to blood creatine kinase levels.","volume":"122","author":"Neal","year":"2009","journal-title":"Am. J. Med."},{"key":"B65","doi-asserted-by":"publisher","DOI":"10.1186\/s40798-018-0138-z","article-title":"Is cardiorespiratory fitness related to cardiometabolic health and all-cause mortality risk in patients with coronary heart disease? A care CR Study.","volume":"4","author":"Nichols","year":"2018","journal-title":"Sports Med. Open"},{"key":"B66","doi-asserted-by":"publisher","first-page":"18550","DOI":"10.1073\/pnas.0509096102","article-title":"Three independent biological mechanisms cause exercise-associated hyponatremia: evidence from 2,135 weighed competitive athletic performances.","volume":"102","author":"Noakes","year":"2005","journal-title":"Proc. Natl. Acad. Sci. U.S.A."},{"key":"B67","doi-asserted-by":"publisher","first-page":"462","DOI":"10.1016\/j.pmedr.2015.05.010","article-title":"Association between self-reported and objectively measured physical fitness level in a middle-aged population in primary care.","volume":"2","author":"Obling","year":"2015","journal-title":"Prev. Med. Rep."},{"key":"B68","doi-asserted-by":"publisher","first-page":"751","DOI":"10.1067\/mhj.2001.114371","article-title":"Effects of prolonged strenuous exercise on plasma levels of atrial natriuretic peptide and brain natriuretic peptide in healthy men.","volume":"141","author":"Ohba","year":"2001","journal-title":"Am. Heart J."},{"key":"B69","doi-asserted-by":"publisher","first-page":"6","DOI":"10.2478\/jomb-2018-0016","article-title":"Acute response to endurance exercise stress: focus on catabolic\/anabolic interplay between cortisol, testosterone, and sex hormone binding globulin in professional athletes.","volume":"38","author":"Popovic","year":"2019","journal-title":"J. Med. Biochem."},{"key":"B70","doi-asserted-by":"publisher","DOI":"10.1007\/s11906-018-0812-z","article-title":"The global epidemic of the metabolic syndrome.","volume":"20","author":"Saklayen","year":"2018","journal-title":"Curr. Hypertens Rep."},{"key":"B71","doi-asserted-by":"publisher","first-page":"267","DOI":"10.1515\/cclm-2013-0601","article-title":"The concentration of high-sensitivity troponin I, galectin-3 and NT-proBNP substantially increase after a 60-km ultramarathon.","volume":"52","author":"Salvagno","year":"2014","journal-title":"Clin. Chem. Lab. Med."},{"key":"B72","doi-asserted-by":"publisher","DOI":"10.21037\/atm.2017.02.31","article-title":"Is the SenseWear Armband accurate enough to quantify and estimate energy expenditure in healthy adults?","volume":"5","author":"Santos-Lozano","year":"2017","journal-title":"Ann. Transl. Med."},{"key":"B73","doi-asserted-by":"publisher","first-page":"57","DOI":"10.1016\/s0736-4679(02)00463-8","article-title":"Cardiac troponins.","volume":"23","author":"Sarko","year":"2002","journal-title":"J. Emerg. Med."},{"key":"B74","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0065596","article-title":"Alterations of Neuromuscular Function after the World\u2019s Most Challenging Mountain Ultra-Marathon.","volume":"8","author":"Saugy","year":"2013","journal-title":"PLoS One"},{"key":"B75","doi-asserted-by":"publisher","first-page":"1408","DOI":"10.1249\/MSS.0b013e318172cf22","article-title":"Exercise-associated increases in cardiac biomarkers.","volume":"40","author":"Scharhag","year":"2008","journal-title":"Med. Sci. Sports Exerc."},{"key":"B76","doi-asserted-by":"publisher","first-page":"1128","DOI":"10.1016\/j.ahj.2005.01.051","article-title":"Independent elevations of N-terminal pro-brain natriuretic peptide and cardiac troponins in endurance athletes after prolonged strenuous exercise.","volume":"150","author":"Scharhag","year":"2005","journal-title":"Am. Heart J."},{"key":"B77","doi-asserted-by":"publisher","first-page":"218","DOI":"10.1007\/s00392-007-0491-2","article-title":"N-terminal B-type natriuretic peptide concentrations are similarly increased by 30 minutes of moderate and brisk walking in patients with coronary artery disease.","volume":"96","author":"Scharhag","year":"2007","journal-title":"Clin. Res. Cardiol."},{"key":"B78","doi-asserted-by":"publisher","first-page":"388","DOI":"10.1097\/01.hjr.0000219117.33038.90","article-title":"Reproducibility and clinical significance of exercise-induced increases in cardiac troponins and N-terminal pro brain natriuretic peptide in endurance athletes.","volume":"13","author":"Scharhag","year":"2006","journal-title":"Eur J. Cardiovasc. Prev. Rehabil."},{"key":"B79","doi-asserted-by":"publisher","first-page":"26","DOI":"10.1249\/MSS.0b013e31818313ff","article-title":"Cardiovascular consequences of completing a 160-km ultramarathon.","volume":"41","author":"Scott","year":"2009","journal-title":"Med. Sci. Sports Exerc."},{"key":"B80","doi-asserted-by":"publisher","first-page":"1246","DOI":"10.1373\/clinchem.2015.240796","article-title":"Biomarker changes after strenuous exercise can mimic pulmonary embolism and cardiac injury\u2013a metaanalysis of 45 studies.","volume":"61","author":"Sedaghat-Hamedani","year":"2015","journal-title":"Clin. Chem."},{"key":"B81","doi-asserted-by":"publisher","first-page":"7","DOI":"10.1093\/ajcn\/47.1.7","article-title":"Lean body mass estimation by bioelectrical impedance analysis: a four-site cross-validation study.","volume":"47","author":"Segal","year":"1988","journal-title":"Am. J. Clin. Nutr."},{"key":"B82","doi-asserted-by":"publisher","first-page":"244","DOI":"10.1111\/j.1600-0838.2009.01042.x","article-title":"The impact of exercise duration and intensity on the release of cardiac biomarkers.","volume":"21","author":"Serrano-Ost\u00e1riz","year":"2011","journal-title":"Scand. J. Med. Sci. Sports"},{"key":"B83","doi-asserted-by":"publisher","first-page":"2099","DOI":"10.1249\/mss.0b013e318153ff78","article-title":"Exercise-induced cardiac troponin T release: a meta-analysis.","volume":"39","author":"Shave","year":"2007","journal-title":"Med. Sci. Sports Exerc."},{"key":"B84","doi-asserted-by":"publisher","first-page":"331","DOI":"10.1093\/ajcn\/77.2.331","article-title":"Development of bioelectrical impedance analysis prediction equations for body composition with the use of a multicomponent model for use in epidemiologic surveys.","volume":"77","author":"Sun","year":"2003","journal-title":"Am. J. Clin. Nutr."},{"key":"B86","doi-asserted-by":"publisher","first-page":"1007","DOI":"10.1080\/02640414.2014.981846","article-title":"Validation of the SenseWear Armband in different ambient temperatures.","volume":"33","author":"Van Hoye","year":"2014","journal-title":"J. Sports Sci."},{"key":"B87","doi-asserted-by":"publisher","first-page":"501","DOI":"10.2143\/AC.70.5.3110509","article-title":"BNP and NT-proBNP elevation after running\u2013a systematic review.","volume":"70","author":"Vilela","year":"2015","journal-title":"Acta Cardiol."},{"key":"B88","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0199790","article-title":"Screen-based sedentary behaviour and adiposity among school children: results from International Study of Childhood Obesity, Lifestyle and the Environment (ISCOLE) - Kenya.","volume":"13","author":"Wachira","year":"2018","journal-title":"PLoS One"},{"key":"B89","doi-asserted-by":"publisher","first-page":"1679","DOI":"10.1007\/s00421-011-2135-5","article-title":"Acute metabolic responses to a 24-h ultra-marathon race in male amateur runners.","volume":"112","author":"Wa\u015bkiewicz","year":"2012","journal-title":"Eur. J. Appl. Physiol."},{"key":"B90","doi-asserted-by":"publisher","DOI":"10.1186\/2046-7648-3-1","article-title":"Age, sex and (the) race: gender and geriatrics in the ultra-endurance age.","volume":"3","author":"Whyte","year":"2014","journal-title":"Extrem. Physiol. Med."},{"key":"B91","doi-asserted-by":"publisher","first-page":"776","DOI":"10.1111\/cpf.12321","article-title":"Two-week test-retest reliability of the Polar\u00a7RS800CXTM to record heart rate variability.","volume":"37","author":"Williams","year":"2017","journal-title":"Clin. Physiol. Funct. Imaging"},{"key":"B92","doi-asserted-by":"publisher","first-page":"542","DOI":"10.1093\/ajcn\/6.5.542","article-title":"Caloric equivalents of gained or lost weight.","volume":"6","author":"Wishnofsky","year":"1958","journal-title":"Am. J. Clin. Nutr."},{"key":"B93","doi-asserted-by":"publisher","first-page":"2711","DOI":"10.3748\/wjg.v10.i18.2711","article-title":"Effects of 24 h ultra-marathon on biochemical and hematological parameters.","volume":"10","author":"Wu","year":"2004","journal-title":"World J. Gastroenterol."},{"key":"B94","first-page":"295","article-title":"Changes in the markers of cardiac damage in men following long-distance and ultra-long-distance running races.","volume":"56","author":"Yoon","year":"2016","journal-title":"J. Sports Med. Phys. Fitness"},{"key":"B95","doi-asserted-by":"publisher","first-page":"7","DOI":"10.2147\/OAJSM.S76490","article-title":"Performance differences between sexes in 50-mile to 3,100-mile ultramarathons.","volume":"6","author":"Zingg","year":"2015","journal-title":"Open Access J. Sports Med."}],"container-title":["Frontiers in Physiology"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fphys.2021.640710\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,3,11]],"date-time":"2021-03-11T07:41:05Z","timestamp":1615448465000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fphys.2021.640710\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,3,11]]},"references-count":92,"alternative-id":["10.3389\/fphys.2021.640710"],"URL":"https:\/\/doi.org\/10.3389\/fphys.2021.640710","relation":{},"ISSN":["1664-042X"],"issn-type":[{"value":"1664-042X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,3,11]]},"article-number":"640710"}}