Current limits for flowmeter resistance in metabolic carts can negatively affect exercise performance. Issue 7 (27th April 2021)

• Record Type: Journal Article
• Authors: Beltrami, Fernando G.; Kurz, Jérôme; Roos, Elena; Spengler, Christina M.
• Is Part Of: Physiological reports. Volume 9:Issue 7(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-04-27
• Subjects: ergospirometry -- exercise testing -- flowmeter -- resistance -- respiratory muscle work -- respiratory muscles; Physiology -- Periodicals; 571
• DOI: 10.14814/phy2.14814
• Languages: English
• ISSNs: 2051-817X

Abstract

Abstract: Purpose: To investigate whether a metabolic cart using a flowmeter in the upper range of accepted resistance to airflow (<1.5 cmH2 O∙L −1 ∙s −1 for flows up to 14 L∙s −1, American Thoracic Society) negatively impacts exercise performance in healthy individuals. Methods: 16 recreationally active males (age 25 ± 1 years, height 180 ± 6 cm, weight 73.5 ± 5.8 kg, all mean ± SD) performed two incremental tests on a bicycle ergometer on each of two visits, using a metabolic cart with a flowmeter of either low (Oxycon Pro) or high (Innocor) airflow resistance. Mouth pressures, gas exchange, blood lactate concentration [La − ], perception of breathlessness, respiratory, and leg exertion were assessed throughout the tests. Results: Tests performed with the Innocor were significantly shorter (15.3 ± 3.2 vs. 15.8 ± 3.3 min, p < 0.0001) and showed higher maximal flow resistance (1.3 ± 0.2 vs. 0.3 ± 0.0 cmH2 O∙L −1 ∙s −1, p < 0.0001). At end‐exercise, peak oxygen consumption (−200 ± 220 ml.min −1, p < 0.0001), minute ventilation (−19.9 ± 10.5 L.min −1, p < 0.0001), breathing frequency (−5.4 ± 5.2 breaths.min −1, p < 0.0001), heart rate (−2.1 ± 3.6 bpm, p = 0.002) and [La − ] (−0.7 ± 1.0 mmol.L −1, p < 0.0001), but not tidal volume (−0.1 ± 0.2 L, p = 0.172) were lower with the Innocor, while the perception of breathlessness was higher (+3.8 ± 5.1 points, p < 0.0001). Conclusions: Airflow resistance in the upper range of current guidelines can significantly affect exercise performance and respiratory pattern in young, healthy males during incremental exercise. The present results indicate the need to revisit guidelines for devices used in ergospirometry. Abstract : Current guidelines allow for respiratory resistance up to 1.5 cmH2 = L/s in metabolic carts. We demonstrate that equipment operating in the upper limit of this range negatively affect exercise performance. Current guidelines should be re‐considered.