There are very few studies that evaluate the correlation between reduced exercise tolerance and subclinical hypothyroidism. In this concern the hormonal reposition using L-thyroxine sodium to treat these patients may stay controversial. To approach this issue we investigated here the effect of L-thyroxine sodium salt administration to individuals with subclinical hypothyroidism to analyze its recovery capability after an acute test of maximal strength in a cycloergometer. In order to evaluate that we measure the plasmatic lactate concentration and the salivary total protein level. This study was conducted with a small group of five female individuals with average age of 51.8±4.9 years old with any clinical signals of hypothyroidism that received the hormone reposition. Blood lactate level and total salivary protein as well as serum concentration of LDL-c, HDL, triglycerides and cholesterol were analyzed after exercise in both condition before and after L-thyroxine therapy.  The test protocol consisted of an initial load of 25W with small increments of 25W intervals at each two minutes until the voluntary exhaustion. The results showed a significant reduction of LDL-c and triglycerides after the normalization of TSH levels with the hormonal reposition (p<0.05). Nevertheless, no differences were observed in the levels of HDL, VLDL and total cholesterol (p<0.05).  On the other hand, while the salivary total protein levels were higher (p=0.004, t-Student test) after the exercise test in the post hormonal condition, the blood lactate concentration did not change (p=0.59) before and after L-thyroxine treatment. Therefore the treatment with L-thyroxine to these patients significantly decrease LDL-c and triglycerides. After the exercise test we could not observe an effective recovery. This suggests that the hormone reposition in the case of subclinical hypothyroidism could be considered when the expectation is to stimulate the practice of physical activity.