| Yazarlar |
Prof. Dr. Oğuz ÖZÇELİK
Kastamonu Üniversitesi, Türkiye |
S. A. Ward
University of Glasgow, United Kingdom |
|
B. J. Whipp
St George’s, University of London, United Kingdom |
| Özet |
| The lactate threshold is a widely used and, at times, controversial construct in exercise physiology and pathophysiology. Its non-invasive estimation during incremental exercise depends upon CO2 output increasing as a function of O2 uptake, i.e. 'V-slope', as a result of bicarbonate buffering during the lactic acidosis. However, we hypothesised that the V-slope deflection could also occur as a consequence of metabolic CO2 being diverted proportionally more into the CO2 stores in the early phase of exercise. Eight healthy males performed two incremental exercise tests on a cycle ergometer, with and without controlled prior hyperventilation; the hyperventilation caused endtidal P(CO2) to decline by ~ 10 mmHg, with the clearance of a CO2 volume averaging 2547 ml. This corresponded to an 'effective' CO2 capacitance of some 3.12 ml mmHg-1 kg-1. Gas exchange was determined breath-by-breath, and blood was sampled from the dorsum of the heated hand. Our results demonstrate that the early dynamics of CO2 wash-in to the previously depleted body stores can result in a 'pseudo-threshold', i.e. significantly before the onset of the actual lactic acidosis. Precautions should therefore be taken to avoid hyperventilation prior to non-invasive estimation of the lactate threshold. |
| Anahtar Kelimeler |
| Makale Türü | Özgün Makale |
| Makale Alt Türü | SSCI, AHCI, SCI, SCI-Exp dergilerinde yayımlanan tam makale |
| Dergi Adı | Experimental Physiology |
| Dergi ISSN | 0958-0670 |
| Dergi Tarandığı Indeksler | SCIexpendad |
| Dergi Grubu | Q2 |
| Makale Dili | İngilizce |
| Basım Tarihi | 12-1999 |
| Cilt No | 84 |
| Sayı | 5 |
| Sayfalar | 999 / 1011 |
| Doi Numarası | 10.1111/j.1469-445X.1999.01868.x |
| Atıf Sayıları | |
| SCOPUS | 43 |
| Google Scholar | 68 |
