Determination of the lactate threshold and maximal blood lactate steady state intensity in aged rats

• Autor(a) principal: Cunha, Rafael Rodrigues
• Data de Publicação: 2009
• Outros Autores: Cunha, Verusca Najara de Carvalho, Segundo, Paulo Russo, Moreira, Sérgio Rodrigues, Kokubun, Eduardo, Campbell, Carmen Sílvia Grubert, Oliveira, Ricardo Jacó de, Simões, Herbert Gustavo
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UCB
• Texto Completo: http://hdl.handle.net/123456789/185; https://repositorio.ucb.br:9443/jspui/handle/123456789/7452
• topic: Anaerobic threshold; Maximal lactate steady state; Swimming exercise; Aging

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 LTwas determined by visual inspection (LTV) as well by applying a polynomial function on the [lac]/workload ratio (LTP) 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%BMfor LTv; and 6.0 0.6 and 5.8 0.6%BMfor 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.