Table 2: Comparison of heart rate variability spectral power (absolute power) in males and females of different age groups ( 𝑛 = 2 5 2 ).

Children AdolescentYoung adultsMiddle-aged

Total power (0–0.4 Hz) (ms2)
Males 2 6 9 4 ± 3 3 6 2 0 7 2 ± 3 0 6 1 1 7 1 ± 2 1 2 5 6 3 ± 1 2 1
(2006–3381) (1446–2697) (736–1606) (313–814)
Females 2 4 3 3 ± 3 3 1 1 6 1 2 ± 2 4 6 1 1 4 8 ± 1 4 9 4 7 8 ± 8 2
(1756–3110) (1112–2112) (846–1456) (308–448)
Total2564 ± 2341822 ± 1941158 ± 124*†520 ± 72*†‡
(2094–3033)(1434–2209)(909–1407) (375–665)

Two-way ANOVA: 𝑃 < 0 . 0 0 1 between age groups, 𝑃 = 0 . 4 2 0 between genders, and 𝑃 = 0 . 3 7 9 for interaction between age and gender.

High-frequency power (0.15–0.4 Hz) (ms2)
Males1645 ± 2091057 ± 165533 ± 98238 ± 56
(1215–2074)(720–1394)(331–734) (121–355)
Females1561 ± 254999 ± 155628 ± 98209 ± 56
(1040–2082)(683–1314)(427–825) (128–289)
Total1603 ± 1631025 ± 112585 ± 69*†223 ± 34*†‡
(1250–1931)(801–1275)(446–724) (155–291)

Two-way ANOVA: 𝑃 < 0 . 0 0 1 between age groups, 𝑃 = 0 . 9 9 5 between genders, and 𝑃 = 0 . 5 9 2 for interaction between age and gender.

Low-frequency power (0.04–0.15 Hz) (ms2)
Males1049 ± 1481001 ± 187638 ± 118325 ± 66
(745–1352)(619–1384)(396–879)(188–461)
Females872 ± 108584 ± 111522 ± 71269 ± 45
(650–1093)(357–812)(377–666)(175–363)
Total960 ± 92760 ± 103573 ± 65*†296 ± 39*†‡
(776–1144)(583–997)(442–703)(217–376)

Two-way ANOVA: 𝑃 < 0 . 0 0 1 between age groups, 𝑃 = 0 . 0 3 4 between genders, and 𝑃 = 0 . 2 3 4 for interaction between age and gender.

Data expressed as mean ± SEM and 95% Confidence Intervals.
*Significantly different from children group.
S ignificantly different from adolescent age group.
S ignificantly different from adult group.
# S ignificantly different from females of same age group.
A ge × Gender = age and gender interaction.