The first part of this post talked about a study that confirmed centuries old reports that through the advanced Vajrayana meditation practice Tummo the core body temperature can be raised significantly. When the forceful breathing practice was combined with the related meditation exercise (as would be the case during this type of meditation), the yogis increased their core temperature by several degrees into the slightly feverish range.
As mentioned in part 1, in addition to recording changes in body temperature the scientists also measured the electrical brain activity with EEG. The most prominent finding here was that one particular brain rhythm, the so-called alpha rhythm (oscillating in the range of 8.5–12.5 Hz), increased in power during forceful breathing. Interestingly, the greater the increase in alpha power achieved during tummo meditation was, the longer the core temperature rose, and the higher the achieved temperature was. New evidence from cognitive neuroscience indicates that this alpha rhythm might reflect that the brain is decreasing the distractibility of ‘‘external’’ sensory events to aid concentration on the internal mental activity. The results thus seem to indicate that the quality of the meditation during forceful breathing, as reflected by increased alpha power, seems to determine for how long the meditators are capable of continuing to raise their body temperature beyond the normal range without reaching an equilibrium phase.
In sum, the study confirms the knowledge from Tibetan Buddhist traditions that the body temperature can be raised through tummo meditation. The authors discuss what the benefits of this ability might be and consider positive effects like adapting to and functioning in cold environments, improving resistance to infections, boosting cognitive performance by speeding response time, etc. However, they also point to another aspect that will probably be of higher importance to the yogis engaging in this advanced form of meditation. Although the rise in body temperature is neither solely a by-product of the meditation nor its final goal, but instead may be a means to facilitate the achievement of ‘‘deep meditative states’’ by enhancing their attention and focus.
There may also be a caveat: As such types of advanced meditations are practiced within a well-defined context, guided by experienced meditation teachers, building on years of personal practice that prepare the meditator and embedded within a complete meditation system, it might be difficult to predict what the results might be, should one try to engage with these exercises without proper preparation and supervision. After all, within Vajrayana traditions such meditations are only passed on to ‘well-prepared’ students, usually within the context of a relatively long retreat. The aim of these meditations would be to provide entry into advanced insight into mind as expounded in the traditions of the Great Seal (Sanskrit: Mahamudra, Tibetan: Chag Chen) and the Great Perfection (Sanskrit: Maha Ati, Tibetan: Dzog Chen).