The Impact Of Acute Hyperglycemia On Heart Rate Variability In Men And Women.

Abstract

BACKGROUND: Heart rate variability (HRV) is used to non-invasively assess autonomic nervous system (ANS) regulation of the heart. Chronic hyperglycemia has been known to reduce HRV; however, no research has examined the impact of acute hyperglycemia on HRV, considering the potential for sex- and menstrual cycle phase-based differences. PURPOSE: To examine the impact of acute hyperglycemia on HRV, in men and women during the early and late follicular phases of the menstrual cycle. METHODS: 41 healthy men and naturally menstruating women (17F, age: 21±1 years) were recruited. Women were assessed during the early and late follicular phases of the menstrual cycle. ‘Ultra short-term’ assessments of HRV (1-minute recordings) were completed using an electrocardiogram before, and 60- and 90-min after consuming a 75g oral glucose challenge. Analysis of HRV time-domain variables was performed. RESULTS: Acute hyperglycemia resulted in elevated HR (shorter R-R intervals) at 60- and 90-min post-glucose ingestion (Pre: 61±1, Post60: 65±1, Post90: 66±1 bpm; p=0.005, p<0.001 respectively), with no differences between men and women, or across phases of the menstrual cycle. The root mean square of successive differences between R-R intervals (RMSSD) and standard deviation in normal R-R intervals (SDNN) were significantly lower Post90 vs Pre (p=0.022, p=0.048 respectively), with no sex differences. Additionally, women, regardless of phase, had higher average HR compared to men (p<0.001). CONCLUSION: Acute hyperglycemia appears to decrease HRV, indicative of an acute change in ANS regulation. Furthermore, this study confirmed previously observed sex differences in HR, but not in HRV. Research supported by: NSERC Discovery Grant & Canadian Graduate Scholarship - Master’s