Table 3. Detrended fluctuation analysis (DFA) as a measure of heart rate variability (HRV) in groups that differ in familial longevity status or chronological age.

	Offspring of long-lived families (N = 37)	Partners of the offspring (N = 36)	Middle-aged* (N = 73)	Young (N = 35)	P value+	P value++
Sleep period
alpha-1 (4–45)	1.09 (0.19)	1.05 (0.22)	1.07 (0.20)	1.08 (0.12)	0.459	0.727
alpha-2 (64–1000)	0.95 (0.12)	0.98 (0.15)	0.96 (0.13)	0.85 (0.11)	0.285	<0.001
Awake period
alpha-1 (4–45)	0.98 (0.15)	0.96 (0.18)	0.98 (0.17)	1.00 (0.13)	0.565	0.465
alpha-2 (64–1000)	1.09 (0.11)	1.11 (0.10)	1.10 (0.10)	1.04 (0.10)	0.331	0.002

Data presented as mean (standard deviation). The linear mixed model analyses between offspring of long-lived parents and their partners as controls were adjusted for sex and calendar age. The linear mixed model analyses between the middle-aged and young groups were adjusted for sex. Alpha-1 represents brief fluctuations and alpha-2 long-term fluctuations.^*Data of offspring and partners combined. ⁺P-value for difference between offspring of long-lived parents and their partners as controls. ⁺⁺P-value for difference between middle-aged group and young.