The Association Between Visceral Fat And Cerebral Blood Flow In Pots Vs. Healthy Adults

Postural Orthostatic Tachycardia Syndrome (POTS) patients experience significant reductions in cerebral blood flow (CBF) during initial orthostasis. Body mass index (BMI) and central obesity have been associated with decreased CBF, yet it is unknown how ectopic fat could contribute to decreased CBF. We hypothesize that higher visceral fat area (VFA) is associated with lower CBF velocity (CBFv) in POTS patients. PURPOSE: To investigate the relationship between visceral fat and CBFv in POTS patients compared to healthy controls. METHODS: A total of 13 participants (4 POTS vs. 9 controls) between the ages of 19-52 years (25.0 ± 4.3 vs. 31.2 ± 12.4 years; p = 0.36) completed a 30-minute bout of semi-recumbent cycling. VFA was measured by bioelectrical impedance analysis at baseline. CBFv was measured using a transcranial Doppler of the middle cerebral artery to determine mean velocity at baseline and during exercise. Independent samples t-tests were conducted to examine differences in body composition and % changes in CBFv from baseline to exercise between POTS and controls. Pearson correlations were used to analyze the relationship between VFA and % changes in CBFv. RESULTS: POTS patients had significantly higher BMI (28.1 ± 3.1 vs. 23.8 ± 2.8 kg/m2; p = 0.03), % body fat (36.4 ± 2.3 vs. 22.7 ± 9.1%; p = 0.01), total body fat mass (30.2 ± 7.5 vs. 16.6 ± 8.5 kg; p = 0.02), and VFA (144.4 ± 45.1 vs. 70.1 ± 48.7cm2; p = 0.03) compared to controls. No significant differences in CBFv at baseline (70.3 ± 22.6 vs. 76.2 ± 12.4 cm/s; p = 0.55) or during exercise (77.7 ± 14.3 vs. 74.6 ± 12.2 cm/s; p = 0.70) were found between POTS patients and controls. There was no significant correlation between VFA and % changes in CBFv from baseline to exercise in POTS or controls (POTS: r = -0.69, p = 0.31; controls: r = 0.50, p = 0.17). CONCLUSION: VFA was not correlated to CBFv in POTS patients or healthy controls, despite POTS patients having higher BMI, body fat, and VFA. Body composition and ectopic fat distribution does not appear to influence changes in CBFv at baseline or during exercise in POTS patients nor young, healthy adults. Supported by: Supported by Falk Department of Exercise Science