Table 1.

Breath-hold (BH) duration, right hemidiaphragm (RHD) position drift, left ventricular (LV) position drift and maximal variation of RR interval variation measured from the BHs performed in a sequential order without (BH#1, BH#2, BH#4) and with (BH#3) supplemental oxygen (4 l/min nasal prong) and hyperventilation in 10 healthy adult subjects (“Healthy Group #1”). Minimum and maximum values are reported in bracket. The second breath-hold (BH#2; no supplemental oxygen or hyperventilation) duration was longer than the first breath-hold confirming the benefit of a training breath-hold with no further benefit of training (BH#4). Still longer breath-holds were achieved with supplemental oxygen and hyperventilation (BH#3). NS indicates no statistical difference.

	Breath-hold duration (s)	RHD position drift (mm)	LV position drift (mm)	Maximum variation of RR interval (beats per minute)
BH #1	35 ± 11(18-53)	4.6 ± 3.3(1-10)	2.7 ± 2.1(0-8)	12 ± 6(5-25)
BH #2	40 ± 14(18-65)	5.9 ± 4.0(2-15)	3.8 ± 2.3(1-9)	14 ± 8(5-30)
BH #3	58 ± 21(27-96)	7.0 ± 4.6(1-18)	4.9 ± 3.9(2-12)	13 ± 5(8-25)
BH #4	41 ± 16(14-60)	6.9 ± 4.2(3-16)	3.4 ± 2.7(1-9)	14 ± 5(8-20)
P BH # vs. #2	0.015	NS	NS	NS
P BH#2 vs. #3	0.005	NS	NS	NS
P BH #3 vs. #4	0.007	NS	NS	NS
P BH #2 vs. #4	NS	NS	NS	NS