Endelig en studie som nevner noen effekter av Zen meditasjon hvor fokus er på å puste veldig sakte, helt ned til 1 pust/min, bl.a. varme. Viser hvordan HRV påvirkes forskjellig, hvor hos noen økes hjerterytmen betraktelig i små perioder, noe som kan være en effekt av ting som skjer under meditasjonen. Desverre innser de at de burde ha målt kroppstemperatur, CO2, blodsirkulasjon og flere parametere for å se tydeligere hva som skjer i kroppen under så sakte pust.
Figure 3 shows pre-Zazen rest period data from a Zen master (KS). This individual breathed close to 6 breaths/min throughout the rest period. Note the comparative absence of high-frequency cardiac variability and the major low-frequency peak at 0.1 Hz. A very-low-frequency peak also is notable. Note the periodic occurrence of irregularities in cardiac rhythm, superimposed on the sinus rhythm, each with a short R-R interval followed by a long one.
Figure 4 shows the last 5-minute period of Zazen from KS. During this period, respiration rate was slowed to less than 1 breath/min. Cardiac variability at this time occurred almost exclusively within the very-low-frequency range (Figure 4), with a power of more than 13 times greater than at rest.
Feelings of Warmth
The participants’ experiences of warmth during Zazen suggest that the body’s thermoregulatory system may have been affected by practice of this discipline. Subject KS, whose very-low-frequency wave amplitudes particularly increased, specifically remarked on his feelings of increased warmth during Zazen. Perhaps breathing at this very slow rate stimulated sympathetic reflexes that affect oscillations in HR within this very-low-frequency range. The meaning of these observations remains ambiguous, however, because we did not specifically examine thermoregulation, vascular tone, blood pressure, or any index of sympathetic activity. Although increases in HR occurred among some Rinzai subjects, these changes were small and not significant. Additional data are required on vascular and body temperature changes during Zazen and their possible relationship with increased sympathetic arousal and HR very-low-frequency wave activity. Previous observations of experienced Indian Yogis have similarly shown significant increases in body temperature during practice of yoga (58).