Abstract
Abstract
Purpose
To quantify the effects of prolonged cycling on the rate of ventilation ($${\dot{\text{V}}}_{{\text{E}}}$$
V
˙
E
), frequency of respiration (FR), and tidal volume (VT) associated with the moderate-to-heavy intensity transition.
Methods
Fourteen endurance-trained cyclists and triathletes (one female) completed an assessment of the moderate-to-heavy intensity transition, determined as the first ventilatory threshold (VT1), before (PRE) and after (POST) two hours of moderate-intensity cycling. The power output, $${\dot{\text{V}}}_{{\text{E}}}$$
V
˙
E
, FR, and VT associated with VT1 were determined PRE and POST.
Results
As previously reported, power output at VT1 significantly decreased by ~ 10% from PRE to POST. The $${\dot{\text{V}}}_{{\text{E}}}$$
V
˙
E
associated with VT1 was unchanged from PRE to POST (72 ± 12 vs. 69 ± 13 L.min−1, ∆ − 3 ± 5 L.min−1, ∆ − 4 ± 8%, P = 0.075), and relatively consistent (within-subject coefficient of variation, 5.4% [3.7, 8.0%]). The $${\dot{\text{V}}}_{{\text{E}}}$$
V
˙
E
associated with VT1 was produced with increased FR (27.6 ± 5.8 vs. 31.9 ± 6.5 breaths.min−1, ∆ 4.3 ± 3.1 breaths.min−1, ∆ 16 ± 11%, P = 0.0002) and decreased VT (2.62 ± 0.43 vs. 2.19 ± 0.36 L.breath−1, ∆ − 0.44 ± 0.22 L.breath−1, ∆ − 16 ± 7%, P = 0.0002) in POST.
Conclusion
These data suggest prolonged exercise shifts ventilatory parameters at the moderate-to-heavy intensity transition, but $${\dot{\text{V}}}_{{\text{E}}}$$
V
˙
E
remains stable. Real-time monitoring of $${\dot{\text{V}}}_{{\text{E}}}$$
V
˙
E
may be a useful means of assessing proximity to the moderate-to-heavy intensity transition during prolonged exercise and is worthy of further research.
Funder
Auckland University of Technology
Publisher
Springer Science and Business Media LLC
Subject
Physiology (medical),Public Health, Environmental and Occupational Health,Orthopedics and Sports Medicine,General Medicine,Public Health, Environmental and Occupational Health,Physiology