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Ghrelin, a gut-brain peptide that signals hunger, is normally suppressed after meals. Subnormal suppression of postprandial ghrelin, previously noted in obese, insulin-resistant individuals, may contribute to increased food intake. Given the ethnic disparities in obesity and obesity-related cardiovascular morbidity in the United States, the present study compared a single postprandial ghrelin measure in 43 women (22 white, 21 black). Each completed a rigorously controlled 4-d dietary intervention designed to maintain weight and constant daily sodium and potassium intake (220 mEq Na, 40 mEq K). Two hours after consuming a test meal of identical content, blood samples were drawn to assess postprandial ghrelin, leptin, and norepinephrine; resting cardiovascular function was measured; and a 24-h urinary cortisol sample was obtained. Independent of body mass index, postprandial ghrelin was significantly higher in black vs. white women, and higher ghrelin was associated with higher cortisol in blacks, who failed to show the expected inverse relation between ghrelin and central obesity seen in whites. Higher ghrelin was correlated with higher blood pressure but lower norepinephrine in obese women. These findings suggest subnormal postprandial ghrelin suppression (or faster ghrelin rebound) in black women, especially the obese, that might play a role in their increased prevalence of obesity and cardiovascular disorders.

Regular physical exercise is known to reduce cardiovascular risk. We examined the effects of a single bout of moderate bicycle exercise on hemodynamic measures at rest and in response to the foot cold pressor (CP) and mental arithmetic (MA). Sedentary males and females (N = 32) were tested twice, following 20 minutes of moderate exercise (exercise day) versus 20 minutes of quiet rest (control day). Although resting blood pressure was no lower 20 minutes after exercise relative to the same time point on the control day, diastolic blood pressure responses to CP (p = .05) and MA (p = .06) were attenuated on the exercise day. Furthermore, recovery from moderate exercise versus control rest was also associated with reduced vascular resistance index (VRI) at rest and during exposure to both stressors (p's < or = .02). VRI reductions were largest in subjects with elevated vascular tone on the control day and were accompanied by increases in heart rate throughout the postexercise period (p's < or = .004) and higher cardiac index during exercise recovery and in response to CP (p's < or = .05). Thus, the cardiovascular benefit of exercise may in part be due to reduced VRI and attenuated cardiovascular responses to stress during the acute postexercise period.

Ambulatory blood pressure (BP) monitoring was undertaken on two days in 31 men and women (11 with elevated resting and ambulatory BP and 20 who were normotensive), once following each of these treatment conditions: 20 min of moderate aerobic bicycle ergometry, and an equivalent control rest period. The two monitoring days were conducted within a 72 h period with the order of treatments counterbalanced across subjects. Mean BP and heart rate (HR) levels were calculated for each individual on an hourly basis and for work, home, and sleep periods, In the elevated BP group, the exercise day compared to the control day was associated with lower BP at work. Hour-by-hour analyses confirmed that the BP-lowering effect of exercise was significant for 5 h and diminished in magnitude between hours 6 and 9. These effects were not attributable to any marked differences in mood, total daily stress, posture, or activities between test days. Exercise was not associated with any appreciable differences in sleep BP or in the 24-h HR profile No differences in BP or HR as a function of exercise were seen in the normotensive group; however, the exercise-induced reduction in mean arterial BP (MAP) for hours 2 through 5 was significantly positively correlated with control day MAP levels at work in the total sample. Thus, moderate aerobic exercise, when engaged in prior to the stresses of daily living, seems to confer a protective reduction in ambulatory BP, particularly in individuals with elevated BP.