Cardiovascular and plasma catecholamine responses to exercise in blacks and whites.

Abstract

The purpose of the present study was to assess possible racial differences in cardiovascular and plasma catecholamine responses to dynamic exercise. A biracial group of normotensive college-age men (15 blacks, 15 whites) were tested for maximal oxygen uptake, resting blood pressure, and heart rate. Subjects then rode a cycle ergometer at 25%, 50%, and 75% of peak oxygen uptake (6 minutes at each stage). Blood pressure and heart rate were measured during supine rest, seated rest, and at each stage of exercise with an automated blood pressure monitor. At each stage, venous blood was sampled to allow determination of plasma norepinephrine and epinephrine, and cardiac output was measured with the carbon dioxide rebreathing technique. The results indicated that resting blood pressure was similar for blacks and whites (114/68 versus 115/68 mm Hg, respectively). Blacks exhibited greater systolic and diastolic blood pressures during submaximal dynamic exercise. However, blacks also showed a trend toward a positive parental history of hypertension, which has been associated with an increased pressor response. Racial differences did not exist for heart rate or cardiac output, but blacks had higher values for total peripheral resistance both at rest and during exercise. Although no overall racial differences were seen for plasma catecholamine concentrations at rest, blacks had significantly lower levels of norepinephrine (1,275 versus 1,556 pg/ml) and higher levels of epinephrine (306 versus 216 pg/ml) than whites at the highest work rate. The current study confirms the increased pressor response to exercise in normotensive blacks. Blacks had an elevation in total peripheral resistance that was not accompanied by an increase in plasma norepinephrine levels.

Effect of interval training programme on pulse pressure in the management of hypertension: A randomized controlled trial

“…Subjects resting BP (SBP, DBP & HR) was monitored from the right arm as described by Walker et al 13 using an automated digital electronic BP monitor (Omron digital BP monitor, Model 11 EM 403c; Tokyo Japan). PP was obtained by subtracting DBP from SBP.…”

Aerobic Exercise Attenuates an Exaggerated Exercise Blood Pressure Response in Normotensive Young Adult African-American Men

“…Aerobic exercise seems to decrease arterial resistance generally [8]. However, the arterial resistance of normotensive African-American males seems to be greater than that of a comparable group of Caucasian-Americans during both exercise and rest [6]. Therefore, we hypothesized that aerobic exercise training may attenuate the EEBPR of normotensive African-American males by the mechanism of reducing arterial resistance.…”

“…Based on a comprehensive review of the scientific literature, Jette et al [4] have concluded that hyper-responders face a 2-10-fold greater probability of developing hypertension. Exaggerated exercise blood pressure responses (EEBPR) have been demonstrated in borderline hypertensives, normotensive individuals with parental histories of hypertension, and African-Americans [3][4][5][6]. Although exercise training at a level that increases aerobic functional work capacity appears to decrease the EEBPR of hypertensive subjects [7], no studies appear to have been performed to determine the effects of exercise training on normotensive subjects exhibiting EEBPR.…”

Normal Exercise Blood Pressure Response in African-American Women with Parental History of Hypertension

“…[12][13][14][15] Although studies have been designed to investigate the pressor response to stressors known to elicit either betaadrenergic (mental challenge) or alpha-adrenergic (cold stress) reactivity in the female offspring of hypertensive African-American parents, [16][17][18] how the blood pressure in African Americans responds to stress eliciting both beta-and alpha-adrenergic reactivity has not been addressed in that population. In the present study, we compared the blood pressure responses in normotensive young adult African-American women with and without a parental history of hypertension during physical exercise, which is known to elicit both betaand alpha-adrenergic reactivity.…”