Is heart rate variability related to memory performance in middle-aged men?

Area of Science:

• Neuroscience
• Cardiology
• Psychology

Background:

• Heart rate variability (HRV), a marker of autonomic nervous system function, has shown inconsistent associations with cognitive abilities.
• Prior research has not adequately controlled for genetic and familial influences on HRV and cognition.

Purpose of the Study:

• To investigate the relationship between HRV and cognitive function, specifically memory and learning, in a controlled twin study.
• To determine if familial and genetic factors confound the association between HRV and cognition.

Main Methods:

• Power spectral analysis of 24-hour ambulatory ECGs was performed on 416 middle-aged male twins.
• Verbal and visual memory were assessed using Selective Reminding Tests (SRTs).
• Mixed-effect regression models were employed to analyze associations within and between twin pairs, adjusting for covariates.

Main Results:

• A significant positive association was observed between HRV measures and verbal SRT scores, but not visual SRT scores.
• Very low frequency HRV showed the strongest association with verbal total recall.
• These associations remained significant after adjusting for demographic, cardiovascular risk factors, and familial/genetic influences. A significant interaction with PTSD was noted.

Conclusions:

• Lower frequency HRV spectra are associated with better verbal learning and memory, particularly in individuals without PTSD.
• The findings suggest that autonomic nervous system dysregulation may contribute to cognitive decline.
• The use of a twin registry allowed for robust control of genetic and environmental factors.