Int J Sports Med 2007; 28(5): 426-430
DOI: 10.1055/s-2006-924367
Clinical Sciences

© Georg Thieme Verlag KG Stuttgart · New York

High-Altitude Exposure Reduces Inspiratory Muscle Strength

V. Fasano2 , E. Paolucci1 , L. Pomidori1 , A. Cogo1
  • 1Department of Clinical and Experimental Medicine, Section of Respiratory Disease, University of Ferrara, Ferrara, Italy
  • 2Institute of Respiratory Diseases, University of Milan, IRCCS Ospedale Maggiore, Milan, Italy
Further Information

Publication History

Accepted after revision: May 20, 2006

Publication Date:
06 October 2006 (online)

Abstract

It was the aim of the study to assess the maximal pressure generated by the inspiratory muscles (MIP) during exposure to different levels of altitude (i.e., hypobaric hypoxia). Eight lowlanders (2 females and 6 males), aged 27 - 46 years, participated in the study. After being evaluated at sea level, the subjects spent seven days at altitudes of more than 3000 metres. On the first day, they rode in a cable car from 1200 to 3200 metres and performed the first test after 45 - 60 minutes rest; they then walked for two hours to a mountain refuge at 3600 metres, where they spent three nights (days 2 - 3); on day 4, they walked for four hours over a glacier to reach Capanna Regina Margherita (4559 m), where they spent days 5 - 7. MIP, flow-volume curve and SpO2 % were measured at each altitude, and acute mountain sickness (Lake Louise score) was recorded. Increasing altitude led to a significant decrease in resting SpO2 % (from 98 % to 80 %) and MIP (from 134 to 111 cmH2O) (baseline to day 4: p < 0.05); there was an improvement in SpO2 % and a slight increase in MIP during the subsequent days at the same altitude. Expiratory (but not inspiratory) flows increased, and forced vital capacity and FEF75 decreased at higher altitudes. We conclude that exposure to high altitude hypoxia reduces the strength of the respiratory muscles, as demonstrated by the reduction in MIP and the lack of an increase in peak inspiratory flows. This reduction is more marked during the first days of exposure to the same altitude, and tends to recover during the acclimatisation process.

References

  • 1 ATS/ERS . Statement on respiratory muscles testing.  Am J Respir Crit Care Med. 2002;  166 518-624
  • 2 Babcock M A, Johnson B D, Pegelow D F, Suman O E, Griffin D, Dempsey J A. Hypoxic effects on exercise-induced diaphragmatic fatigue in normal healthy humans.  J Appl Physiol. 1995;  78 82-92
  • 3 Basnyat B, Murdoch D R. High-altitude illness.  Lancet. 2003;  361 1967-1974
  • 4 Cibella F, Cuttitta G, Kayser B, Narici M, Romano S, Saibene F. Respiratory mechanics during exhaustive submaximal exercise at high altitude in healthy humans.  J Physiol. 1996;  494 881-890
  • 5 Cogo A, Legnani D, Allegra L. Respiratory function at different altitudes.  Respiration. 1997;  64 416-421
  • 6 Crapo R. Pulmonary function testing.  N Eng J Med. 1994;  331 25-30
  • 7 Cremona G, Asnaghi R, Baderna P, Brunetto A, Brutsaert T, Cavallaro C, Clark T M, Cogo A, Donis R, Lanfranchi P, Luks A, Novello N, Panzetta S, Perini L, Putnam M, Spagnolatti L, Wagner H, Wagner P D. Pulmonary extravascular fluid accumulation in recreational climbers: a prospective study.  Lancet. 2002;  359 303-309
  • 8 Dawson S V, Elliott E A. Wave-speed limitation on expiratory flow: a unifying concept.  J Appl Physiol. 1977;  43 498-515
  • 9 Dempsey J A, Schoene R B. Pulmonary system adaptation to high altitude. Bone RC Pulmonary and Critical Care Medicine. (B6). Saint Louis; Mosby Year Book 1994: 1-22
  • 10 Deboeck G, Moraine J J, Naeije R. Respiratory muscle strength may explain hypoxia-induced decrease in vital capacity.  Med Sci Sports Exerc. 2005;  37 754-758
  • 11 Forte V A, Leith D E, Muza S R, Fulco C S, Cymerman A. Ventilatory capacities at sea level and high altitude.  Aviat Space Environ Med. 1997;  69 488-493
  • 12 Grippi M, Metzger L F, Krupinsky A V, Fishman A P. Pulmonary function testing. Fishman AP Pulmonary Disease and Disorders. New York; Mc Graw Hill Book Company 1988: 2469-2551
  • 13 Gudjonsdottir M, Appendini L, Baderna P, Purro A, Patessio A, Vilianis G, Pastorelli M, Sigurdsson S B, Donner C F. Diaphragm fatigue during exercise at high altitude: the role of hypoxia and workload.  Eur Respir J. 2001;  17 674-680
  • 14 Incalzi R A, Fuso L, Ricci T, Sammarro S, Dicorcia A, Albano A, Pistelli R. Acute oxygen supplementation does not relieve the impairment of respiratory muscle strength in hypoxemic COPD.  Chest. 1998;  113 334-339
  • 15 Jaeger J J, Sylvester J T, Cymerman A, Berberich J J, Denniston J C, Maher J T. Evidence for increased intrathoracic fluid volume in man at high altitude.  J Appl Physiol. 1979;  47 670-676
  • 16 Jardim J, Farkas G, Prefaut C, Thomas D, Macklem P T, Roussos C H. The failing inspiratory muscles under normoxic and hypoxic conditions.  Am Rev Respir Dis. 1981;  124 274-279
  • 17 Mannix E T, Sullivan T Y, Palange P, Dowdeswell I R, Manfredi F, Galassetti P, Farber M O. Metabolic basis for inspiratory muscle fatigue in normal humans.  J Appl Physiol. 1993;  75 2188-2194
  • 18 Mason N P, Barry P W, Pollard A J, Collier D J, Taub N A, Miller M R, Milledge J S. Serial changes in spirometry during an ascent to 5300 m in the Nepalese Himalayas.  High Alt Med Biol. 2000;  1 185-195
  • 19 Mason N P, Petersen M, Melot C, Imanow B, Matveykine O, Gautier M T, Sarybaev A, Aldashev A, Mirrakhimov M M, Brown B H, Leathard A D, Naeije R. Serial changes in nasal potential difference and lung electrical impedance tomography at high altitude.  J Appl Physiol. 2003;  94 2043-2050
  • 20 McConnell A K, Romer L M. Dyspnoea in health and obstructive pulmonary disease: the role of respiratory muscle function and training.  Sports Med. 2004;  34 117-132
  • 21 Miller M R, Hankinson J, Brusasco V, Burgos F, Casaburi R, Coates A, Crapo R, Enright P, van der Grinten C P, Gustafsson P, Jensen R, Johnson D C, MacIntyre N, McKay R, Navajas D, Pedersen O F, Pellegrino R, Viegi G, Wanger J. Standardisation of spirometry.  Eur Respir J. 2005;  26 319-338
  • 22 Mosso (ed) A. Fisiologia Dell'Uomo Sulle Alpi. Torino; Treves 1897
  • 23 Pollard A J, Mason N P, Barry P W, Pollard R C, Collier D J, Fraser R S, Miller M R, Milledge J S. Effect of altitude on spirometric parameters and the performance of peak flowmeters.  Thorax. 1996;  51 175-178
  • 24 NHLBI Workshop summary . Respiratory muscle fatigue. Report of the Respiratory Muscle Fatigue Workshop Group.  Am Rev Respir Dis. 1990;  142 474-480
  • 25 Roach R, Bartsch P, Hackett P, Oelz O. The Lake Louise acute mountain sickness scoring system. Sutton JR, Houston CS, Coates G Hypoxia and Molecular Medicine. Burlington; Queen City Printers 1993: 272-274
  • 26 Schoene R B. Limits of human lung function at high altitude.  J Exp Biol. 2001;  204 3121-3127
  • 27 Stuessi C, Spengler C M, Knopfli-Lenzin C, Markov G, Boutellier U. Respiratory muscle endurance training in humans increases cycling endurance without affecting blood gas concentrations.  Eur J Appl Physiol. 2001;  84 582-586
  • 28 Welsh C H, Wagner P D, Reeves J T, Lynch D, Cink T M, Armstrong J, Malconian M K, Rock P B, Houston C S. Operation Everest II. Spirometric and radiographic changes in acclimatized humans at simulated high altitudes.  Am Rev Respir Dis. 1993;  147 1239-1244
  • 29 West J B. High altitude. Crystal RG, West JB The Lung. New York; Raven Press 1991: 2093-2107

Annalisa Cogo

Clinica Malattie Respiratorie
Università degli Studi di Ferrara

Via Savonarola 9

44100 Ferrara

Italy

Phone: + 39 05 32 21 04 20

Fax: + 39 05 32 21 02 97

Email: annalisa.cogo@unife.it