5. Study Limitations
hypoxia, ’
HYPOXIA
To the best of our knowledge, our study is the first in which the effect of DAA supplementation was assessed in normobaric hypoxia during the LH–TL protocol. Our experiment, however, is not without certain limitations. Firstly, we did not measure the levels of the analyzed indicators immediately before the initial exposure to hypoxia. An additional point of measurement would have allowed for a precise determination of whether there was a change in blood T levels after 4 days of DAA supplementation and whether the rise in T levels during S2 was due to hypoxia alone or the combined influence of DAA and hypoxia. However, logistical constraints (related to the athletes’ arrival at the training camp) prevented us from taking measurements on that particular day. Secondly, it would have been advantageous to determine the concentrations of DAA and D-aspartate oxidase in the blood. Such data would enable us to understand if oral DAA supplementation significantly alters the levels of DAA and D-aspartate oxidase in the blood. Future research should also consider a longer DAA supplementation period prior to altitude training and possibly using a 3 g/day dosage, as there are some indications that a 6 g/day dosage may lead to reduced T and fT concentrations [