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Determination of the lactate threshold and maximal blood lactate steady state intensity in aged rats
Author(s) -
Cunha Rafael Rodrigues,
de Carvalho Cunha Verusca Najara,
Segundo Paulo Russo,
Moreira Sérgio Rodrigues,
Kokubun Eduardo,
Campbell Carmen Sílvia Grubert,
Jacó de Oliveira Ricardo,
Simões Herbert Gustavo
Publication year - 2009
Publication title -
cell biochemistry and function
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 61
eISSN - 1099-0844
pISSN - 0263-6484
DOI - 10.1002/cbf.1580
Subject(s) - blood lactate , lactate threshold , exercise intensity , intensity (physics) , steady state (chemistry) , zoology , chemistry , medicine , mathematics , biology , physics , heart rate , quantum mechanics , blood pressure
The reliability of the lactate threshold (LT) determined in aged rats and its validity to identify an exercise intensity corresponding to the maximal blood lactate steady state (MLSS) were analyzed. Eighteen male aged Wistar rats (∼365 days) were submitted to two incremental swimming tests until exhaustion, consisting of an initial load corresponding to 1% of body mass (BM) and increments of 1% BM at each 3‐min with blood lactate ([lac]) measurements. The LT was determined by visual inspection (LT V ) as well by applying a polynomial function on the [lac]/workload ratio (LT P ) by considering the vertices of the curve. For the MLSS, twelve animals were submitted, on different days, to 3–4 exercise sessions of 30‐min with workload corresponding to 4, 5 or 6% BM. The MLSS was considered the highest exercise intensity at which the [lac] variation was not higher than 0.07 mM.min −1 during the last 20‐min. No differences were observed for the test‐retest results (4.9 ± 0.7 and 5.0 ± 0.8 %BM for LTv; and 6.0 ± 0.6 and 5.8 ± 0.6 %BM for LTp) that did not differ from the MLSS (5.4 ± 0.5 %BM). The LT identified for aged rats in swimming, both by visual inspection and polynomial function, was reliable and did not differ from the MLSS. Copyright © 2009 John Wiley & Sons, Ltd.