Cardiorespiratory Changes During Prolonged Downhill Versus Uphill Treadmill Exercise

Abstract

Oxygen uptake (V̇O₂), heart rate (HR), energy cost (E_C) and oxygen pulse are lower during downhill compared to level or uphill locomotion. However, a change in oxygen pulse and E_C during prolonged grade exercise is not well documented. This study investigated changes in cardiorespiratory responses and E_C during 45-min grade exercises. Nine male healthy volunteers randomly ran at 75% HR reserve during 45-min exercise in a level (+1%), uphill (+15%) or downhill (−15%) condition. V̇O₂ , minute ventilation (V̇_E ) and end-tidal carbon dioxide (P_etCO₂) were recorded continuously with 5-min averaging between the 10^th and 15^th min (T1) and 40^th and 45^th min (T2). For a similar HR (157±3 bpm), V̇O₂ , V̇_E , and P_etCO₂ were lower during downhill compared to level and uphill conditions (p<0.01). V̇O₂ and V̇_E decreased similarly from T1 to T2 for all conditions (all p<0.01), while P_etCO₂ decreased only for the downhill condition (p<0.001). Uphill exercise required greater E_C compared to level and downhill exercises. E_C decreased only during the uphill condition between T1 and T2 (p<0.01). The lowest V̇O₂ and E_C during downhill exercise compared to uphill and level exercises suggests the involvement of passive elastic structures in force production during downhill. The lower cardiorespiratory response and the reduction in P_etCO₂ during downhill running exercise, while E_C remained constant, suggests an overdrive ventilation pattern likely due to a greater stimulation of efferent neural factors.

Key words

treadmill running - oxygen uptake - uphill - downhill - energy cost

• References

• 1 Davies CTM, Sargeant AJ, Smith B. The physiological responses to running downhill. Eur J Appl Physiol Occup Physiol 1974; 32: 187-194
• 2 Maciejczyk M, Więcek M, Szymura J. et al. Comparison of physiological and acid-base balance response during uphill, level and downhill running performed at constant velocity. Acta Physiol Hung 2013; 100: 347-354
• 3 Lemire M, Lonsdorfer-Wolf E, Isner-Horobeti M-E. et al. Cardiorespiratory responses to downhill versus uphill running in endurance athletes. Res Q Exerc Sport 2018; 89: 511-517
• 4 Westerlind KC, Byrnes WC, Harris C. et al. Alterations in oxygen consumption during and between bouts of level and downhill running. Med Sci Sports Exerc 1994; 26: 1144-1152
• 5 Whipp BJ, Higgenbotham MB, Cobb FC. Estimating exercise stroke volume from asymptotic oxygen pulse in humans. J Appl Physiol (1985) 1996; 81: 2674-2679
• 6 Dufour SP, Doutreleau S, Lonsdorfer-Wolf E. et al. Deciphering the metabolic and mechanical contributions to the exercise-induced circulatory response: Insights from eccentric cycling. Am J Physiol Regul Integr Comp Physiol 2007; 292: R1641-R1648
• 7 Peñailillo L, Blazevich AJ, Nosaka K. Factors contributing to lower metabolic demand of eccentric compared with concentric cycling. J Appl Physiol (1985) 2017; 123: 884-893
• 8 Dzal YA, Jenkin SEM, Lague SL. et al. Oxygen in demand: How oxygen has shaped vertebrate physiology. Comp Biochem Physiol A Mol Integr Physiol 2015; 186: 4-26
• 9 Dick RW, Cavanagh PR. An explanation of the upward drift in oxygen uptake during prolonged sub-maximal downhill running. Med Sci Sports Exerc 1987; 19: 310-317
• 10 Minetti AE, Ardigò LP, Saibene F. Mechanical determinants of the minimum energy cost of gradient running in humans. J Exp Biol 1994; 195: 211-225
• 11 Vernillo G, Giandolini M, Edwards WB. et al. Biomechanics and physiology of uphill and downhill running. Sports Med 2017; 47: 615-629
• 12 Barnes KR, Kilding AE. Running economy: measurement, norms, and determining factors. Sports Med Open 2015; 1: 8
• 13 Mizrahi J, Verbitsky O, Isakov E. Fatigue-induced changes in decline running. Clin Biomech 2001; 16: 207-212
• 14 Zuccarelli L, Porcelli S, Rasica L. et al. Comparison between slow components of HR and VO₂ kinetics: Functional significance. Med Sci Sports Exerc 2018; 50: 1649-1657
• 15 Harriss DJ, Macsween A, Atkinson G. Standards for ethics in sport and exercise science research: 2020 update. Int J Sports Med 2019; 40: 813-817
• 16 Karvonen J, Vuorimaa T. Heart rate and exercise intensity during sports activities. Practical application. Sports Med 1988; 5: 303-311
• 17 Rodríguez-Marroyo JA, González-Lázaro J, Arribas-Cubero HF. et al. Physiological demands of mountain running races. Kinesiology 2018; 50 60-66
• 18 Fornasiero A, Savoldelli A, Fruet D. et al. Physiological intensity profile, exercise load and performance predictors of a 65-km mountain ultra-marathon. J Sports Sci 2018; 36: 1287-1295
• 19 Minetti AE, Moia C, Roi GS. et al. Energy cost of walking and running at extreme uphill and downhill slopes. J Appl Physiol (1985) 2002; 93: 1039-1046
• 20 Assadi H, Lepers R. Comparison of the 45-second/15-second intermittent running field test and the continuous treadmill test. Int J Sports Physiol Perform 2012; 7: 277-284
• 21 Péronnet F, Massicotte D. Table of nonprotein respiratory quotient: an update. Can J Sport Sci 1991; 16: 23-29
• 22 Faul F, Erdfelder E, Lang AG. et al. G*Power3: A flexible statistical power analysis program for the social, behavioral, and biomedical sciences. Behav Res Methods 2007; 39: 175-191
• 23 Lechauve JB, Perrault H, Aguilaniu B. et al. Breathing patterns during eccentric exercise. Respir Physiol Neurobiol 2014; 202: 53-58
• 24 Takano N. Phase relation and breathing pattern during locomotor/respiratory coupling in uphill and downhill running. Jpn J Physiol 1995; 45: 47-58
• 25 McMurray RG, Smith LG. Ventilatory responses when altering stride frequency at a constant oxygen uptake. Respir Physiol 1985; 62: 117-124
• 26 Hammo AH, Weinberger MM. Exercise-induced hyperventilation: A pseudoasthma syndrome. Ann Allergy Asthma Immunol 1999; 82: 574-578
• 27 Trinity JD, Amann M, McDaniel J. et al. Limb movement-induced hyperemia has a central hemodynamic component: Evidence from a neural blockade study. Am J Physiol Heart Circ Physiol 2010; 299: H1693-H1700
• 28 Gladwell VF, Coote JH. Heart rate at the onset of muscle contraction and during passive muscle stretch in humans: A role for mechanoreceptors. J Physiol 2002; 540: 1095-1102
• 29 Hotta N, Yamamoto K, Ogata H. et al. Does degree of alteration in effort sense caused by eccentric exercise significantly affect initial exercise hyperpnea in humans?. J Physiol Anthropol 2016; 35: 18
• 30 Abe D, Fukuoka Y, Muraki S. et al. Effects of load and gradient on energy cost of running. J Physiol Anthropol 2011; 30: 153-160
• 31 Herzog W. The role of titin in eccentric muscle contraction. J Exp Biol 2014; 217: 2825-2833
• 32 Boushel R. Muscle metaboreflex control of the circulation during exercise. Acta Physiol (Oxf) 2010; 199: 367-383
• 33 Giovanelli N, Ortiz AL, Henninger K. et al. Energetics of vertical kilometer foot races; is steeper cheaper?. J Appl Physiol (1985) 2016; 120: 370-375