The Effect of Exertional Hypertension Evoked by Weight Lifting on Vascular Endothelial Function

Abstract

To the Editor: Chronic hypertension is associated with arterial endothelial dysfunction, the precursor to atherosclerosis (1); however, less is known about the effects of brief episodes of hypertension on endothelial function. Lamping and Dole (2) demonstrated that Ͻ5 min of moderate elevations in perfusion pressure reduces conduit coronary arterial endothelial function for up to 2.5 h. This endothelial dysfunction also extends to the human microcirculation (3).Cardiovascular benefits of exercise extend to both aerobic and resistance exercise and include improved endothelial function (4). However, weight lifting elevates systolic blood pressure (SBP) up to 400 mm Hg (5), possibly impairing endothelial function. We examined whether brief elevations in arterial pressure during weight lifting impair brachial arterial endothelial function assessed by flow-mediated vasodilation (FMD).Nine men and 5 women, age 28 Ϯ 2 years (mean Ϯ SE), who engaged in regular weight training (1 h, 3 times per week) constituted the conditioned weight lifter (CWL) group. Eleven men and 5 women, age 33 Ϯ 2 years, who did not regularly engage in exercise constituted the non-weight lifter (NWL) group. Those with known risk factors for coronary endothelial dysfunction or with prior adverse reaction to nitroglycerin were excluded. The Institutional Review Board of the Medical College of Wisconsin and of the local General Clinical Research Center approved the protocol.Brachial artery FMD was assessed before and within 1 h after leg press exercise. Ultrasound imaging of brachial artery diameter and flow velocity was performed using standard methods (6) at baseline and after a 4.5-min suprasystolic blood pressure cuff inflation. This process was repeated after 30 min of resistance exercise, followed by assessment of endothelium-independent vasodilation using 0.4 mg sublingual nitroglycerin (NTG).Diastolic brachial artery diameters were digitally recorded from longitudinal images and analyzed using an automated edgedetection algorithm (Medical Imaging, Iowa City, Iowa). Percentage dilation was calculated from baseline to peak values obtained after cuff release (FMD) or NTG.Subjects performed 2 to 3 sets of 6 to 8 repetitions each to near maximal exertion, serving as their own controls. Brachial artery diameter, FMD before and after weight lifting, peak SBP during exercise versus baseline were each compared using a paired t test. Changes in FMD (%) between groups were compared using an unpaired t test. Correlations between FMD before and after exercise were made using Pearson correlates. Data are reported as mean Ϯ SE with p Ͻ 0.05 considered to be significant.The mean age of all subjects was 31 Ϯ 1 (range 21 to 40) years. There were no differences in arterial blood pressure, heart rate, or lipid profiles between CWL and NWL groups, and these values were within the normal range (data not shown). However, 1 CWL and 1 NWL subject had previously undetected hypercholesterolemia (LDL 181 and 170 mg/dl, respectively) but normal FMD and were included in a...

Comparative study of the upper and lower limb skin blood flow control mechanisms in patients with essential hypertension

“…In a study, Padilla et al (17) have shown that the brachial artery endothelial vasodilatation was impaired following increase in blood pressure but poplietal artery endothelial function was unaltered. Similar result is found in a study that used the leg press exercise to increase the blood pressure (32).…”

Effects of muscle contraction timing during resistance training on vascular function

“…These findings are consistent with those of a previous study that showed that chronic resistance training may protect against the adverse effects of acute resistance exercise-associated hypertension by preserving vascular endothelial function. 33 Our observations, as well as those of others, 32 may reflect obvious differences in the mechanisms responsible for endothelial regulation of arterial tone on changes in arterial stiffness and/or vascular endothelial function caused by resistance training.…”

Circuit Resistance Training Attenuates Acute Exertion-Induced Reductions in Arterial Function but Not Inflammation in Obese Women

“…Of note, the RPE scale was not used as an intensity threshold because the perceived capacity was 85%-95% of predicted 10-RM and the goal was to elicit similar increases in blood pressure between participants. 12 …”

“…Resistance exercise is known to have beneficial effects on CVD risk factors [8][9][10][11] and is also associated with improvements in conduit artery flow-mediated vasodilation (FMD), 12 which is an index of EF and NO bioavailability in humans. However, previous studies performed in our laboratory and others indicate that FMD is markedly reduced following acute bouts of resistance exercise in obese women and sedentary individuals unaccustomed to exercise training.…”

“…Paradoxically, cross-sectional studies indicate that exerciseinduced reductions in FMD are not apparent in trained populations who regularly engage in exercise. 12,16 Given that obesity and sedentary lifestyle independently contribute to low-grade inflammation 17,18 and reduced NO bioavailability, 13,19 it is plausible to hypothesize that inflammation may be a critical factor mediating postexercise reductions in FMD among obese and sedentary populations.…”