Autonomic dysfunction precedes cardiometabolic alterations in a metabolic syndrome model: impact of aerobic exercise training

Abstract

The aim was to evaluate the effects of exercise training (T) on the time course of cardiometabolic alterations in hypertensive rats (SHR) submitted to fructose overload. Wistar and SHR rats were divided: Control (C), Hypertension (H), Hypertensive + Fructose (HF) and Hypertensive Fructose + Exercise Training (HFT). The fructose overload (100g / L) was initiated 30 days after weaning of the animals. The T was performed on a treadmill (1H / d, 5d / week). The evaluations were performed at 37, 45, 60 and 90 days of life of animals. Blood pressure (BP) and heart rate (HR) were directly recorded through an acquisition system. Cardiovascular autonomic modulation was evaluated in the time and frequency domain. The H and HF groups showed an increase in VAR‐SAP compared to C group at all times. The consumption of fructose induced a further rise of the VAR‐SAP at 45 and 90 days vs. 37 days, which was not observed with the T. The H group showed an increase in LF‐SAP (vascular sympathetic) at 60 and 90 days compared to C group. However, the HF group showed an increase in VAR‐SAP at 45, 60 and 90 days compared to C group and their values in 37 days, with an additional increase in 90 days (40%) vs. H group. The H group showed a decrease in HF‐PI (cardiac parasympathetic) in 37 days and the HF group at 37 and 90 days compared to C group. The HFT group had higher RMSSD and VAR‐PI at 37 and 90 days compared to C group. The spontaneous baroreflex sensitivity was lower in H and HF groups in all times evaluated and the T increased this variable in 60 (79%) and 90 days (72%) vs. HF group. The H and HF groups showed an increase of BP in the all evaluated times compared to C group. (165±3; 179±3 vs. 114±1 mmHg) The fructose induced an additional increase in BP at 90 days and T reduced these values. The HFT group showed a HR reduction in 60 (11%) and 90 (7%) days vs. HF group. There were no significant changes in blood triglycerides and glucose in all evaluated times. The cardiovascular autonomic dysfunction seems to precede hemodynamic and metabolic changes in this experimental model of metabolic syndrome. Moreover, exercise training was effective in attenuate the time course of autonomic and hemodynamic dysfunctions.Support or Funding InformationFinancial Support: FAPESP (2015/11223‐6); CNPq (457200/2014‐6); CAPES (PROSUP).