For a long time, it was known that exercise is good not only for the muscles, but also for the bones. And it looks like the lactate is one of the reasons for that:
pubmed.ncbi.nlm.nih.gov
Also, bicarbonate helps to increase the lactate during the exercise:
pubmed.ncbi.nlm.nih.gov
Lactate Mediates the Bone Anabolic Effect of High-Intensity Interval Training by Inducing Osteoblast Differentiation - PubMed
Lactate may mediate the bone anabolic effect of HIIT and serve as a potential inexpensive therapeutic strategy for bone augmentation.
pubmed.ncbi.nlm.nih.gov
Also, bicarbonate helps to increase the lactate during the exercise:
High doses of sodium bicarbonate increase lactate levels and delay exhaustion in a cycling performance test - PubMed
The present study found that 0.3 g · kg<sup>-1</sup> BW NaHCO<sub>3</sub> is effective in improving performance and improving blood lactate levels in cyclists compared with control and 0.1 g · kg<sup>-1</sup> BW NaHCO<sub>3.</sub>
pubmed.ncbi.nlm.nih.gov