Cyclic variation in heart rate during sleep in four recordings of up to 13 years in elderly adults

To characterize changes in nighttime cyclic variation in HR (CVHR) with advancing age in older adults, CVHR was quantified for N=56 adults with 2 Holter recordings 5 yrs apart (CHS1 and CHS 2) in the cardiovascular health study (CHS) and 2 overnight polysomnograms 5 yrs apart in the sleep heart health study (SHHS1 and SHHS2) using MatLab. Baseline age was 71plusmn3 yrs. The number of CVHR events was also normalized to time in bed (CVHR index). CVHR index did not change across recordings, but males had higher values (p=0.009). Mean HR increase during CVHR was similar in the first 3 recording but declined on the last (p