Original articles   

The Journal of Sports Medicine and Physical Fitness 2001 June;41(2):189-95

Copyright © 2002 EDIZIONI MINERVA MEDICA

lingua: Inglese

Effect of nostril dilatation on prolonged all-out intermittent exercise performance

Tong T. K. °, Fu F. H. °, Chow B. C. *

From the ° Dr. Stephen Hui Research Center for Physical Recreation and Wellness * Department of Physical Education Hong Kong Baptist University, Hong Kong, China

Background. This ­study was ­designed to exam­ine wheth­er nos­tril dil­a­ta­tion ­would ­affect the ven­til­a­to­ry mus­cle (VM) func­tion and the ­mean pow­er out­put (PO) dur­ing pro­longed all-out inter­mit­tent exer­cise.
Methods. Eight ­untrained ­young ­male sub­jects ­each com­plet­ed 30 ­bouts of all-out exer­cise 20-sec ­each on a ­cycle ergom­e­ter inter­spersed ­with 40-sec recov­ery peri­ods ­under (i) nor­mal breath­ing and (ii) nos­tril dil­a­ta­tion con­di­tions. For nos­tril dil­a­ta­tion, exter­nal ­nasal dila­tor (END) was ­used. Pre-exer­cise ­peak ­nasal inspir­a­to­ry ­flow (­PNIF), pre- and ­postexer­cise max­i­mum inspir­a­to­ry (MIP) and expir­a­to­ry pres­sures ­were ­assessed in all ­trials. During exer­cise, rat­ings of per­ceived mag­ni­tude of breath­ing ­effort (­RPMBE) and exer­tion (RPE) ­were record­ed at 5-min inter­vals ­while ven­ti­la­tion, ­tidal vol­ume, breath­ing fre­quen­cy and oxy­gen con­sump­tion (V.O2) ­were meas­ured at 20-sec inter­vals.
Results. Inspiratory mus­cle ­fatigue ­occurred dur­ing con­trol ­trial as MIP ­reduced ­from 155.1±25.3 cm H2O to 140.5±31.2 cm H2O ­after the exer­cise. Pre-exer­cise ­PNIF was ­increased ­with END ­from 3.1±0.8 l.sec-1 to 3.8±1.0 l.sec-1 show­ing ­that the ­nasal air­flow resis­tance was ­reduced. Using END dur­ing exer­cise elim­i­nat­ed inspir­a­to­ry mus­cle ­fatigue (no ­change in ­post-exer­cise MIP), and result­ed in low aver­age ­RPMBE and RPE, and ­high PO in com­par­i­son ­with the con­trol val­ues. In addi­tion, the aug­men­ta­tion of PO was con­com­i­tant ­with no ­change in the aver­age val­ues of the V.O2 and the ven­til­a­to­ry param­e­ters.
Conclusions. Exercise-­induced VM ­fatigue ­occurs dur­ing the pro­longed all-out inter­mit­tent exer­cise. Nostril dil­a­ta­tion ­with END dur­ing the exer­cise ­results in elim­i­nat­ing the VM ­fatigue and improv­ing the PO.