Age, gender, and nycthemeral-dependent normal ranges are necessary for accurate HRV assessment due to significant age-related declines in nocturnal parasympathetic activity.
Normal aging is associated with a constant decline of cardiac vagal modulation due to a significant decrease of nocturnal parasympathetic activity. The significant gender-related difference of HRV decreases with aging. These findings emphasize the need to determine age-, gender-, and nycthemeral-dependent normal ranges for HRV assessment.
Bonnemeier et al. (Tue,) studied this question.