1.
Association Between Occupational, Sport, and Leisure Related Physical Activity and Baroreflex Sensitivity: The Paris Prospective Study III.
Climie, RE, Boutouyrie, P, Perier, MC, Chaussade, E, Plichart, M, Offredo, L, Guibout, C, van Sloten, TT, Thomas, F, Pannier, B, et al
Hypertension (Dallas, Tex. : 1979). 2019;(6):1476-1483
Abstract
Physical activity (PA) is a preventative behavior for noncommunicable disease. However, little consideration is given as to whether different domains of PA have differing associations with health outcomes. We sought to determine the association between occupational, sport, leisure, and total PA with baroreflex sensitivity (BRS), distinguishing between neural (nBRS) and mechanical (mBRS) BRS. In a cross-sectional analysis of 8649 adults aged 50 to 75 years, resting nBRS (estimated by low-frequency gain, from carotid distension rate and heart rate) and mBRS (carotid stiffness) were measured by high-precision carotid echo-tracking. PA was self-reported using the validated Baecke questionnaire. The associations between PA and nBRS and mBRS were quantified using multivariate linear regression analysis, separately in the working and nonworking population. In working adults (n=5039), occupational PA was associated with worse nBRS (unstandardized β=-0.02; [95% CI, -0.04 to -0.003]; P=0.022) whereas sport PA was associated with better nBRS (β=0.04; [95% CI, 0.02-0.07]; P=0.003) and mBRS (β=-0.05; [95% CI, -0.09 to -0.00001]; P=0.049). Neither leisure PA nor total PA was associated with nBRS or mBRS. In nonworking adults (n=3610), sport PA and total PA were associated with better mBRS (β=-0.08; [95% CI, -0.15 to 0.02]; P=0.012 and β=-0.05; [95% CI, -0.10 to 0.009]; P=0.018) but not nBRS. These findings suggest differential associations between domains of PA and BRS and may provide insights into the mechanisms underlying the association between occupational PA and cardiovascular disease.
2.
The osmopressor response is linked to upregulation of aquaporin-1 tyrosine phosphorylation on red blood cell membranes.
Chu, YH, Hsu, YJ, Lee, HS, Ho, ST, Tung, CS, Tseng, CJ, Li, MH, Lin, TC, Lu, CC
Hypertension (Dallas, Tex. : 1979). 2013;(1):197-202
Abstract
Studies in patients with an impaired efferent baroreflex led us to discover that ingesting water induces a robust increase in blood pressure and vascular resistance. This response was also present in healthy subjects with intact baroreflexes, described as osmopressor response. This study was to discover the physiology of the osmopressor response by determining functional activation of the aquaporin-1 water channel receptor on red blood cell membranes in young healthy subjects. In a randomized, controlled, crossover fashion, 22 young healthy subjects (age, 19-27 years) ingested either 500 or 50 mL of water. Heart rate, blood pressure, cardiac index, and total peripheral vascular resistance were measured using a Finometer hemodynamic monitor. Blood sampling was performed at 5 minutes before and at 25 and 50 minutes after either the water ingestion or control session. Immunoblotting for aquaporin-1 tyrosine phosphorylation was performed before and after subjects ingested either 500 or 50 mL of water. At 25 minutes after the ingestion of 500 mL of water, total peripheral resistance increased significantly, and plasma osmolality decreased. Functional expression of aquaporin-1 tyrosine phosphorylation on red blood cell membranes increased significantly at 25 and 50 minutes after subjects ingested 500 mL of water compared with that before water ingestion. This study concludes that water ingestion produces upregulation of aquaporin-1 tyrosine phosphorylation on red blood cell, which presents as a novel biological marker that occurs simultaneously with the osmopressor response.
3.
Exercise training improves baroreflex sensitivity in type 2 diabetes.
Loimaala, A, Huikuri, HV, Kööbi, T, Rinne, M, Nenonen, A, Vuori, I
Diabetes. 2003;(7):1837-42
Abstract
Type 2 diabetes is a strong risk factor for coronary heart disease and sudden cardiac death. It is associated with reduced baroreflex sensitivity (BRS) and heart rate variability (HRV), which are indicators of increased risk for mortality and morbidity in various patient populations. This study was designed to assess the effects of exercise training on BRS, HRV, and hemodynamics in patients with type 2 diabetes. Subjects (50 men, mean age 53.3 +/- 5.1 years) with type 2 diabetes were randomized into either a control group, in which they received conventional treatment only, or an exercise group, in which they received conventional treatment together with heart rate-controlled endurance training twice a week and supervised muscle strength training twice a week for 12 months. Measurements taken at baseline and follow-up included VO(2max), standard time and frequency domain measures of HRV during 24-h recording, and BRS by the phenylephrine method. Cardiac index, systemic vascular resistance index, stroke index, and pulse wave velocity were measured by whole-body impedance cardiography. Significant improvements in VO(2max) (exercise group: +2.3 ml x kg(-1) x min(-1); P < 0.005 vs. control group), muscle strength, and glycemic control (exercise group: HbA(1c) -0.9%; P < 0.001 vs. control group) were observed in the exercise group. BRS increased in the exercise group, from 6.8 to 8.6 ms/mmHg, and decreased in the control group, from 7.5 to 6.4 ms/mmHg (95% CI for the difference between 0.05 and 4.36 ms/mmHg; P < 0.05). No significant changes in the time or frequency domain measures of HRV or in systemic hemodynamics were observed. We concluded that exercise training improves BRS sensitivity in type 2 diabetes subjects in addition to increasing the exercise capacity and muscle strength and improving glucose control. These beneficial effects in reflectory autonomic regulation and glucose control caused by exercise may be associated with improved prognosis of type 2 diabetes patients.