Resumen

CUNHA, Verusca N. C. et al. Eight weeks of moderate exercise training does not change the load corresponding to lactate threshold in old-age rats. Rev. Port. Cien. Desp. [online]. 2008, vol.8, n.2, pp.277-283. ISSN 1645-0523.

Objective: To analyze in elderly rats the effect of eight weeks of aerobic training in corresponding load to the lactate threshold. Methods: Seventeen elderly rats (~ 478 days/life) had been divided in Trained-T, n=11 and Control-C, n=6. They underwent an incremental test before and after 8 weeks of swimming training (30 min/day, 5/weekly, ~5% body weight) or control without exercise. Incremental test was carried out with increments of 1% body weight each 3 minutes until exhaustion. Lactate threshold was identified by polynomial adjustment of the ratio lactate/workload. After experimental period animals were sacrificed for calculation of the ratio weight of the heart/body weight. Results: lactate threshold did not demonstrate significant difference with training in both groups (T:pre=5.1±0.7/post=5.3±0.7%PC;C:pre=6.1±0.4/post=6.4±0.6%PC;p>0.05). When calculated the variation of the body weight before and after training, significant difference between groups was evidenced (T=-1.5±2.4% vs. C=6.4±3.3%;p<0.0001). A 13% difference was observed in the ratio weight of heart/body weight between groups (T=0.29±0.04 vs. C=0.25±0.03;p<0.05). Conclusion: Although alterations in the ratio weight of heart/body weight indicate possible cardiovascular benefits because of training, the used protocol did not result in improvement of aerobic capacity evaluated by lactate threshold in elderly rats.

Palabras clave : lactate threshold; swimming; elderly animals; training.

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