Caloric restriction and intermittent fasting alter spectral measures of heart rate and blood pressure variability in rats

TLDR

Dietary restriction extends lifespan, delays age‑related diseases, and improves cardiovascular risk factors in rodents and other species. The study examined how dietary restriction affects beat‑to‑beat heart rate and diastolic blood pressure variability in male Sprague‑Dawley rats. Telemetric transmitters recorded heart rate and diastolic blood pressure, and power spectral analysis evaluated low‑ and high‑frequency components to assess autonomic activity. Dietary restriction lowered body weight, heart rate, systolic and diastolic blood pressure, reduced sympathetic tone (low‑frequency DPV), increased parasympathetic activity (high‑frequency HRV), with effects peaking after one month and reverting quickly after resuming ad libitum feeding, indicating a cardiovascular benefit that warrants human studies.

Abstract

Dietary restriction (DR) has been shown to increase life span, delay or prevent age-associated diseases, and improve functional and metabolic cardiovascular risk factors in rodents and other species. To investigate the effects of DR on beat-to-beat heart rate and diastolic blood pressure variability (HRV and DPV) in male Sprague-Dawley rats, we implanted telemetric transmitters and animals were maintained on either intermittent fasting (every other day feeding) or calorie-restricted (40% caloric reduction) diets. Using power spectral analysis, we evaluated the temporal profiles of the low- and high-frequency oscillatory components in heart rate and diastolic blood pressure signals to assess cardiac autonomic activity. Body weight, heart rate, and systolic and diastolic blood pressure were all found to decrease in response to DR. Both methods of DR produced decreases in the low-frequency component of DPV spectra, a marker for sympathetic tone, and the high-frequency component of HRV spectra, a marker for parasympathetic activity, was increased. These parameters required at least 1 month to become maximal, but returned toward baseline values rapidly once rats resumed ad libitum diets. These results suggest an additional cardiovascular benefit of DR that merits further studies of this potential effect in humans.