Open AccessRespiratory frequency and tidal volume during exercise: differential control and unbalanced interdependence
Author(s) -
Nicolò Andrea,
Girardi Michele,
Bazzucchi Ilenia,
Felici Francesco,
Sacchetti Massimo
Publication year - 2018
Publication title -
physiological reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 39
ISSN - 2051-817X
DOI - 10.14814/phy2.13908
Subject(s) - workload , rating of perceived exertion , respiratory minute volume , medicine , tidal volume , respiratory frequency , cardiology , ventilation (architecture) , test (biology) , differential effects , physical therapy , respiratory system , ventilatory threshold , physical medicine and rehabilitation , heart rate , vo2 max , computer science , physics , blood pressure , paleontology , biology , thermodynamics , operating system
Differentiating between respiratory frequency ( f R ) and tidal volume ( V T ) may improve our understanding of exercise hyperpnoea because f R and V T seem to be regulated by different inputs. We designed a series of exercise manipulations to improve our understanding of how f R and V T are regulated during exercise. Twelve cyclists performed an incremental test and three randomized experimental sessions in separate visits. In two of the three experimental visits, participants performed a moderate‐intensity sinusoidal test followed, after recovery, by a moderate‐to‐severe‐intensity sinusoidal test. These two visits differed in the period of the sinusoid (2 min vs. 8 min). In the third experimental visit, participants performed a trapezoidal test where the workload was self‐paced in order to match a predefined trapezoidal template of rating of perceived exertion ( RPE ). The results collectively reveal that f R changes more with RPE than with workload, gas exchange, V T or the amount of muscle activation. However, f R dissociates from RPE during moderate exercise. Both V T and minute ventilation ( V ˙ E ) showed a similar time course and a large correlation withV ˙ CO 2 in all the tests. Nevertheless,V ˙ CO 2was associated more withV ˙ E than with V T because V T seems to adjust continuously on the basis of f R levels to matchV ˙ E withV ˙ CO 2 . The present findings provide novel insight into the differential control of f R and V T – and their unbalanced interdependence – during exercise. The emerging conceptual framework is expected to guide future research on the mechanisms underlying the long‐debated issue of exercise hyperpnoea.