Effect of sex difference and pregnancy on the normal reactive hyperemia curve

1977 ◽  
Vol 233 (4) ◽  
pp. H500-H504
Author(s):  
J. K. Vyden ◽  
T. Takano ◽  
K. Nagasawa ◽  
T. Ogawa ◽  
M. Groseth-Robertson ◽  
...  
Keyword(s):  
Blood Flow ◽  
Sex Difference ◽  
Vascular Reactivity ◽  
Forearm Blood Flow ◽  
Circulatory Arrest ◽  
Reactive Hyperemia ◽  
Normal Male ◽  
Normal Female ◽  
The Mean ◽  
Normal Males

The 10-min reactive hyperemia reaction was studied in a group of normal males, 10 normal females, 10 females in each trimester of pregnancy, and 10 females 6 wk postpartum. Sex difference had a marked effect on the hyperemic reaction, in that 5 and 15 s after release of circulatory arrest, the mean forearm blood flow in normal males was significantly reduced below that of normal females. During pregnancy there was a shift in the reaction of the pregnant female toward that in the normal male. In the 1st trimester of pregnancy, 5 s after circulatory arrest the mean forearm blood flow was diminished below that of the normal female; in the 2nd and 3rd trimesters at 5 s, the reaction was significantly diminished below that of the normal female. At 6wk postpartum, the reaction was essentially the same as in the nonpregnant female. Although these changes may be explained by a hormonal difference, they portray that there may be a marked difference in vascular reactivity due to sex difference only.

Head-down-tilt bed rest alters forearm vasodilator and vasoconstrictor responses

1998 ◽  
Vol 84 (5) ◽  
pp. 1756-1762 ◽  
Author(s):  
J. Kevin Shoemaker ◽  
Cindy S. Hogeman ◽  
David H. Silber ◽  
Kristen Gray ◽  
Michael Herr ◽  
...  
Keyword(s):  
Blood Flow ◽  
Vascular Reactivity ◽  
Forearm Blood Flow ◽  
Circulatory Arrest ◽  
Cold Pressor Test ◽  
Cold Pressor ◽  
Bed Rest ◽  
Venous Occlusion ◽  
Pressor Test ◽  
Sympathetic Discharge

To test the hypothesis that head-down-tilt bed rest (HDBR) for 14 days alters vascular reactivity to vasodilatory and vasoconstrictor stimuli, the reactive hyperemic forearm blood flow (RHBF, measured by venous occlusion plethysmography) and mean arterial pressure (MAP, measured by Finapres) responses after 10 min of circulatory arrest were measured in a control trial ( n = 20) and when sympathetic discharge was increased by a cold pressor test (RHBF + cold pressor test; n = 10). Vascular conductance (VC) was calculated (VC = RHBF/MAP). In the control trial, peak RHBF at 5 s after circulatory arrest (34.1 ± 2.5 vs. 48.9 ± 4.3 ml ⋅ 100 ml−1 ⋅ min−1) and VC (0.34 ± 0.02 vs. 0.53 ± 0.05 ml ⋅ 100 ml−1 ⋅ min−1 ⋅ mmHg−1) were reduced in the post- compared with the pre-HDBR tests ( P < 0.05). Total excess RHBF over 3 min was diminished in the post- compared with the pre-HDBR trial (84.8 vs. 117 ml/100 ml, P < 0.002). The ability of the cold pressor test to lower forearm blood flow was less in the post- than in the pre-HDBR test ( P < 0.05), despite similar increases in MAP. These data suggest that regulation of vascular dilation and the interaction between dilatory and constrictor influences were altered with bed rest.

Peak calf blood flow estimates are higher with Dohn than with Whitney plethysmograph

1996 ◽  
Vol 81 (3) ◽  
pp. 1418-1422 ◽  
Author(s):  
D. N. Proctor ◽  
J. R. Halliwill ◽  
P. H. Shen ◽  
N. E. Vlahakis ◽  
M. J. Joyner
Keyword(s):  
Blood Flow ◽  
Reactive Hyperemia ◽  
Arterial Occlusion ◽  
Venous Occlusion ◽  
Calf Blood Flow ◽  
Absolute Flow ◽  
Wide Range ◽  
Before And After ◽  
The Mean ◽  
Highly Correlated

Estimates of calf blood flow with venous occlusion plethysmography vary widely between studies, perhaps due to the use of different plethysmographs. Consequently, we compared calf blood flow estimates at rest and during reactive hyperemia in eight healthy subjects (four men and four women) with two commonly used plethysmographs: the mercury-in-silastic (Whitney) strain gauge and Dohn air-filled cuff. To minimize technical variability, flow estimates were compared with a Whitney gauge and a Dohn cuff on opposite calves before and after 10 min of bilateral femoral arterial occlusion. To account for any differences between limbs, a second trial was conducted in which the plethysmographs were switched. Resting flows did not differ between the plethysmographs (P = 0.096), but a trend toward lower values with the Whitney was apparent. Peak flows averaged 37% lower with the Whitney (27.8 +/- 2.8 ml.dl-1.min-1) than with the Dohn plethysmograph (44.4 +/- 2.8 ml.dl-1.min-1; P < 0.05). Peak flow expressed as a multiple above baseline was also lower with the Whitney (10-fold) than with the Dohn plethysmograph (14.5-fold; P = 0.02). Across all flows at rest and during reactive hyperemia, estimates were highly correlated between the plethysmographs in all subjects (r2 = 0.96-0.99). However, the mean slope for the Whitney-Dohn relationship was only 60 +/- 2%, indicating that over a wide range of flows the Whitney gauge estimate was 40% lower than that for the Dohn cuff. These results demonstrate that the same qualitative results can be obtained with either plethysmograph but that absolute flow values will generally be lower with Whitney gauges.

Sensitivity of Digital Thermal Monitoring Parameters to Reactive Hyperemia

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Mohammad W. Akhtar ◽  
Stanley J. Kleis ◽  
Ralph W. Metcalfe ◽  
Morteza Naghavi
Keyword(s):  
Blood Flow ◽  
Flow Rate ◽  
Vascular Reactivity ◽  
Early Stage ◽  
Reactive Hyperemia ◽  
Assessment Tools ◽  
Functional Evaluation ◽  
Thermal Monitoring ◽  
Essential Components ◽  
Baseline Flow

Both structural and functional evaluations of the endothelium exist in order to diagnose cardiovascular disease (CVD) in its asymptomatic stages. Vascular reactivity, a functional evaluation of the endothelium in response to factors such as occlusion, cold, and stress, in addition to plasma markers, is the most widely accepted test and has been found to be a better predictor of the health of the endothelium than structural assessment tools such as coronary calcium scores or carotid intima-media thickness. Among the vascular reactivity assessment techniques available, digital thermal monitoring (DTM) is a noninvasive technique that measures the recovery of fingertip temperature after 2–5 min of brachial occlusion. On release of occlusion, the finger temperature responds to the amount of blood flow rate overshoot referred to as reactive hyperemia (RH), which has been shown to correlate with vascular health. Recent clinical trials have confirmed the potential importance of DTM as an early stage predictor of CVD. Numerical simulations of a finger were carried out to establish the relationship between DTM and RH. The model finger consisted of essential components including bone, tissue, major blood vessels (macrovasculature), skin, and microvasculature. The macrovasculature was represented by a pair of arteries and veins, while the microvasculature was represented by a porous medium. The time-dependent Navier–Stokes and energy equations were numerically solved to describe the temperature distribution in and around the finger. The blood flow waveform postocclusion, an input to the numerical model, was modeled as an instantaneous overshoot in flow rate (RH) followed by an exponential decay back to baseline flow rate. Simulation results were similar to clinically measured fingertip temperature profiles in terms of basic shape, temperature variations, and time delays at time scales associated with both heat conduction and blood perfusion. The DTM parameters currently in clinical use were evaluated and their sensitivity to RH was established. Among the parameters presented, temperature rebound (TR) was shown to have the best correlation with the level of RH with good sensitivity for the range of flow rates studied. It was shown that both TR and the equilibrium start temperature (representing the baseline flow rate) are necessary to identify the amount of RH and, thus, to establish criteria for predicting the state of specific patient’s cardiovascular health.

Forearm Vasoreactivity in Type I Diabetic Subjects

2001 ◽  
Vol 26 (1) ◽  
pp. 34-43 ◽  
Author(s):  
Jason D. Allen ◽  
Michael Welsch ◽  
Nikki Aucoin ◽  
Robert Wood ◽  
Matt Lee ◽  
...  
Keyword(s):  
Risk Factors ◽  
Blood Flow ◽  
Vascular Function ◽  
Forearm Blood Flow ◽  
Reactive Hyperemia ◽  
Arterial Occlusion ◽  
Type I ◽  
Handgrip Exercise ◽  
Blood Flows

This study compared forearm vasoreactivity in 15 Type 1 diabetic subjects with 15 healthy controls. The groups were matched for age, exercise capacity, and the absence of other cardiovascular risk factors. Vasoreactivity was measured using strain gauge plethysmography, at rest, after arterial occlusion (OCC), and following OCC coupled with handgrip exercise (ROCC). Forearm blood flows were significantly elevated between conditions 2.58 ± 0.37 ml/100mltissue at rest to 26.80 ± 6.56 after OCC and 32.80 ± 8.26ml/100mltissue following ROCC in Type 1 diabetic subjects. There were no differences in forearm blood flow between groups for any of the conditions. These data indicate the degree of forearm blood flow is directly related to the intensity of the vasodilatory stimulus. However, our study did not reveal evidence of impaired vasodilatory capacity in Type 1 diabetic subjects compared to controls in the absence of other risk factors. Key words: IDDM, vascular function, exercise, fitness, and reactive hyperemia

Metabolic Effect and Uptake of [3H]Digoxin in the Forearm of Man

1972 ◽  
Vol 42 (5) ◽  
pp. 567-577
Author(s):  
R. I. Ogilvie ◽  
G. A. Klassen
Keyword(s):  
Blood Flow ◽  
Oleic Acid ◽  
Forearm Blood Flow ◽  
Digoxin Concentration ◽  
Normal Male ◽  
Ethanol Group ◽  
Arterial Blood ◽  
Electrolyte Flux ◽  
Arterial Plasma

1. The forearm perfusion technique was used to study the effect of intra-arterial injections of ethanol with or without digoxin on the metabolism and electrolyte flux of forearm tissues in normal male volunteers. 2. In six subjects infusion of ethanol alone (2·9 mg/min over 30 min) resulted in no alterations of forearm blood flow, O2 consumption, carbohydrate metabolism, or flux of potassium and calcium. Although there was no change in extraction of [14C]oleic acid, a significant net output of oleic and total free fatty acids was observed from both deep venous and superficial venous systems. 3. In six subjects the intra-arterial infusion of [3H]digoxin (0·09 μg/min with ethanol, 2·9 mg/min over 30 min) resulted in no alteration of forearm blood flow. During the steady state achieved after 5–8 min of perfusion, 50·3% of the calculated local arterial plasma digoxin concentration of 2·73 μg/l was extracted by the deep venous system with a significant increase in glucose extraction. The respiratory quotient and fractional utilization of O2 by glucose increased. No change in extraction of [14C]oleic acid from arterial blood was observed. However, the net output of oleic and total free acids from both deep and superficial venous systems was insignificant in comparison with that observed in the ethanol control subjects. The changes in K+ flux were similar to those noted in the ethanol group. In the post-digoxin period there was a significantly increased uptake of Ca2+ by forearm tissues. 4. This is the first demonstration of the stimulatory effects of digoxin on glucose metabolism, the antilipolytic effects of this drug and its effect on Ca2+ fluxes in vivo in man.

scholarly journals Cardiovascular and Autonomic Responses after a Single Bout of Resistance Exercise in Men with Untreated Stage 2 Hypertension

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Marcus Vinicius Machado ◽  
Thais de Paola Chequer Barbosa ◽  
Thais Camasmine Chrispino ◽  
Fabricia Junqueira das Neves ◽  
Gabriel Dias Rodrigues ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Resistance Exercise ◽  
Vascular Reactivity ◽  
Forearm Blood Flow ◽  
Area Under The Curve ◽  
Venous Occlusion ◽  
Antihypertensive Medications ◽  
Single Bout

The aim of this paper is to assess the integrated responses of ambulatory blood pressure (BP), cardiac autonomic modulation, spontaneous baroreflex sensitivity (BRS), and vascular reactivity after a single bout of resistance exercise (RE) in men with stage 2 hypertension who have never been treated before. Ten hypertensive men were subjected to a RE session of three sets of 20 repetitions and an intensity of 40% of the 1-repetition maximum (RM) test in seven different exercises. For the control (CTR) session, the volunteers were positioned on the exercise machines but did not perform any exercise. Forearm blood flow was measured by venous occlusion plethysmography. We also analyzed the heart rate variability (HRV), ambulatory BP, blood pressure variability (BPV), and BRS. All measurements were performed at different timepoints: baseline, 20 min, 80 min, and 24 h after both RE and CTR sessions. There were no differences in ambulatory BP over the 24 h between the RE and CTR sessions. However, the area under the curve of diastolic BP decreased after the RE session. Heart rate (HR) and cardiac output increased for up to 80 and 20 min after RE, respectively. Similarly, forearm blood flow, conductance, and vascular reactivity increased 20 min after RE ( p < 0.05 ). In contrast, HRV and BRS decreased immediately after exercise and remained lower for 20 min after RE. We conclude that a single bout of RE induced an increase in vascular reactivity and reduced the pressure load by attenuating AUC of DBP in hypertensive individuals who had never been treated with antihypertensive medications.

scholarly journals PO-087 4-weeks hypoxia (HHL) training improves rowers’ cutaneous microcirculation

2018 ◽  
Vol 1 (3) ◽  
Author(s):  
Zhijun Meng ◽  
Binghong Gao
Keyword(s):  
Blood Flow ◽  
Endothelial Function ◽  
Forearm Blood Flow ◽  
Early Stage ◽  
Reactive Hyperemia ◽  
Peripheral Circulation ◽  
Reserve Capacity ◽  
Hypoxic Training ◽  
Cutaneous Microcirculation ◽  
Traditional Research

Objective Sport scientists always pay attention to cardiorespiratory and hematologic system on benefit of hypoxic training, but peripheral circulation may be one of these benefit, which is one cause of improving performance. So, in order to know whether or not hypoxic training affect athletes’ cutaneous microcirculation, we test rowers’ microcirculation for 4 weeks’ High Live-High Train-Low exercise(HHL). Methods The subject is 21 male rowers of Shanghai rowing team.12 of them take part in 4 weeks HHL (train and live at 2500m, exercise at 100m), while 9 of them train in normoxia. Forearm and leg cutaneous blood flow(CBF) was measured using a laser doppler flowmeter (PeriFlux600, Perimed, Sweden) at room temperature (22℃) with subject lying position and after testing in that position for at least 10min. We tested the forearm and leg blood flow, and also the blood flow when localized heating to 44℃ for 3 mins. Microvascular reactivity(MVR) was evaluated form the maximal post occlusive reactive hyperemia(PORH) following 3-min forearm ischemia produced by cuff inflation (200mm Hg). Similar procedures have been used by other investigators. Blood pressure was measured by brachial auscultation. SPO2 and heart rate was measured by a hand hold pulse oximeter (NONIN, 9500, USA) .The blood flow was measured 4 times, baseline, 1stweek, 3rdweek and post. Results Blood flow and CMBC of forearm of HHL increased significantly at 1stweek(8.9,13.0;112.0,151.0,P<0.05), but thigh and NOM group did not increase. The lowest and highest blood flow of PORH both increase at 1stweek(2,9,3.2;46.0,53.0;0.05<P<0.1). At 3rdweek, HHL group’s resting blood flow and CMBC of forearm is lower than 1stweek(9.3,13.0;124.5,151.0), but higher than pretraining, but velocity of blood flow decreased(8.2,9.2).  These results suggest at early stage of HHL, vasoconstriction may be dominant. But when rowers suffer more and more hypoxia, vasodilation and angiogenesis may play a key role in their skin blood flow. At 3rdweek after training, the blood flow and CMBC are similar with baseline. Conclusions 4 weeks HHL training of rowers increase forearm blood flow, but no thigh. This is because thigh is main working muscle of rowers, which may be affected by training status and fatigue. And also, PORH reserve capacity is an indicator of endothelial function. In this study, we find HHL rowers increase their PORH reserve capacity, which means endothelial function is improved by hypoxia training. So, besides the traditional research of Hematologic System on hypoxia training, we find 4 weeks HHL training increase forearm blood flow and improve endothelial function. This may be one mechanism of improving performance, which need more studies to confirm.

Inhibition of vascular ATP-sensitive K+channels does not affect reactive hyperemia in human forearm

2003 ◽  
Vol 284 (2) ◽  
pp. H711-H718 ◽  
Author(s):  
H. M. Omar Farouque ◽  
Ian T. Meredith
Keyword(s):  
Blood Flow ◽  
Adaptive Response ◽  
Healthy Subjects ◽  
Forearm Blood Flow ◽  
Reactive Hyperemia ◽  
Venous Occlusion ◽  
Channel Inhibition ◽  
Human Forearm ◽  
Hyperemic Response

The extent to which ATP-sensitive K+ channels contribute to reactive hyperemia in humans is unresolved. We examined the role of ATP-sensitive K+channels in regulating reactive hyperemia induced by 5 min of forearm ischemia. Thirty-one healthy subjects had forearm blood flow measured with venous occlusion plethysmography. Reactive hyperemia could be reproducibly induced ( n = 9). The contribution of vascular ATP-sensitive K+ channels to reactive hyperemia was determined by measuring forearm blood flow before and during brachial artery infusion of glibenclamide, an ATP-sensitive K+ channel inhibitor ( n = 12). To document ATP-sensitive K+ channel inhibition with glibenclamide, coinfusion with diazoxide, an ATP-sensitive K+ channel opener, was undertaken ( n = 10). Glibenclamide did not significantly alter resting forearm blood flow or the initial and sustained phases of reactive hyperemia. However, glibenclamide attenuated the hyperemic response induced by diazoxide. These data suggest that ATP-sensitive K+ channels do not play an important role in controlling forearm reactive hyperemia and that other mechanisms are active in this adaptive response.

scholarly journals Activation of ATP-sensitive potassium channels contributes to reactive hyperemia in humans

1996 ◽  
Vol 271 (4) ◽  
pp. H1594-H1598 ◽  
Author(s):  
P. F. Banitt ◽  
P. Smits ◽  
S. B. Williams ◽  
P. Ganz ◽  
M. A. Creager
Keyword(s):  
Blood Flow ◽  
Katp Channel ◽  
Forearm Blood Flow ◽  
Reactive Hyperemia ◽  
Katp Channels ◽  
Venous Occlusion ◽  
Membrane Hyperpolarization ◽  
Flow Response ◽  
Hyperemic Flow ◽  
Basal Flow

Activation of ATP-sensitive potassium (KATP) channels present on vascular smooth muscle cells causes membrane hyperpolarization and vasodilation. The purpose of this study was to determine whether KATP channels contribute to reactive hyperemia in humans. Accordingly, we studied the effect of tolbutamide, a KATP channel inhibitor, on reactive hyperemic forearm blood flow. Forearm blood flow was measured by venous occlusion plethysmography. Forearm ischemia was produced by inflating a sphygmomanometric cuff on the arm to suprasystolic pressures for 5 min. After cuff release, forearm blood flow was measured during the reactive hyperemic phase for 5 min. Tolbutamide (1 mM blood concentration, n = 6) did not affect basal (2.4 +/- 0.2 to 2.2 +/- 0.1 ml.100 ml-1.min-1) or peak reactive hyperemic forearm blood flow (21.9 +/- 3.8 to 22.6 +/- 2.9 ml.100 ml-1.min-1, each P = NS), but it significantly attenuated total hyperemic volume (12.6 +/- 1.7 vs. 9.2 +/- 1.8 ml/100 ml, P < 0.02). Vehicle (n = 6) did not affect basal flow, peak reactive hyperemic flow, or total hyperemia. To determine whether adenosine or endothelium-derived nitric oxide contribute to reactive hyperemia via KATP channels, adenosine (1.5-500 micro grams/min, n = 6) and acetylcholine (30 micrograms/min, n = 6) were infused before and during tolbutamide coinfusion. Tolbutamide did not significantly alter the forearm blood flow response to either adenosine or acetylcholine. In conclusion, KATP channels contribute to vasodilation during reactive hyperemia in humans.

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