Sir,
I read the recent publication on yoga and mental health with great interest.[1] Gururaja et al. concluded that “yoga has both immediate and long-term effects on anxiety reduction”.[1] I agree that yoga has good effect on mental health. However, I have a concern on the technique for verification of the result in this study. The authors used the salivary amylase measurement and further extrapolated it to mental health. Indeed, there are many considerations on salivary amylase measurement in this work. First, there is no data on quality control and control of confounding factors. Control of measurement technique, eating behavior as well as underlying oral pathology are important things to be discussed.[2] Second, although salivary amylase might be feasible to use as an indicator for stress, it implies acute stress not the mental health. The use of cortisol might be better.
REFERENCES
- 1.Gururaja D, Harano K, Toyotake I, Kobayashi H. Effect of yoga on mental health: Comparative study between young and senior subjects in Japan. Int J Yoga. 2011;4:7–12. doi: 10.4103/0973-6131.78173. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Okabe H, Uji Y, Netsu K, Noma A. Automated measurement of amylase isoenzymes with 4-nitrophenyl-maltoheptaoside as substrate and use of a selective amylase inhibitor. Clin Chem. 1984;30:1219–22. [PubMed] [Google Scholar]