From a sample size PoV, 12 does not even matter, because they are looking for specific phyisiological responses and correlations. Its also good that they don't have a causal hypothesis statement:
> These results could have important implications for the treatment of conditions associated with excessive or persistent inflammation, such as autoimmune diseases.
Because there are a lot of confounds in making causal inferences. I hope they will they do a larger N study..
Thanks for asking this question. However, sample size is pretty large. There is a whole community of Sadhus and monks practising this for centuries. This is simply a part of Yoga.
Sample size seems small because Wim wants to hide his sources. See my other comment[1].
> These results could have important implications for the treatment of conditions associated with excessive or persistent inflammation, such as autoimmune diseases.
Because there are a lot of confounds in making causal inferences. I hope they will they do a larger N study..