Transcendental Meditation done for 20 min reduced oxygen consumption by 17 percent (Wallace, Benson, &Wilson, 1971). This was believed to be due to reduced mental arousal and reduced muscular activity. Similarly, a 15 percent decrease in oxygen consumption followed meditation on a meaningful syllable (Telles, Nagarathna, & Nagendra, 1995). In contrast, two studies on a single subject practicing yoga breathing (ujjayi pranayama) reported increases in oxygen consumption by 19 percent and 9 percent, respectively during the practice (Miles, 1964; Rao, 1968).
More recent studies on groups of yoga trainees showed that other yoga breathing practices also increased oxygen consumption by an average of 28 percent following a month of practice (Telles, Nagarathna, & Nagendra, 1994) and by an average of 17 percent as an immediate effect of 45 min of practice (Telles, Nagarathna, & Nagendra, 1996). The metabolic rate increased, both during a sitting (Rai&Ram, 1993) and a standing yoga posture (Rai, Ram, Kant, Madan, & Sharma, 1994), when these postures were compared with supine rest and with sitting in a chair. In particular, the standing yoga posture, virasan, induces a hypermetabolic state with increased sympathetic activity,
which disappears when the subject adopts a supine posture (shavasan). ...