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C France

Publications and source records attributed to C France.

10 recordsLinked to original sources
PubMed1992

Cardiovascular responses to the combination of caffeine and mental arithmetic, cold pressor, and static exercise stressors.

The present study examined cardiovascular responses to the combination of caffeine (250mg) and mental arithmetic, cold pressor, and static exercise stressors in 48 healthy males. Subjects were tested in a within-subject, placebo-controlled, double-blind design. Repeated measurements of heart rate, finger temperature, respiratory sinus arrhythmia, forearm blood flow, and blood pressure were obtained during a pre-drug resting baseline, a post-drug resting baseline, the three stressor tasks, and a recovery baseline. The primary analyses were 2(Drug) x 5(Period) x 6(Stress Order) MANCOVAs using pre-drug baseline values as covariates. Significant period main effects were observed for all measures. Significant drug main effects were observed for blood pressure, finger temperature, respiratory sinus arrhythmia, and forearm blood flow. The significant changes in blood pressure and finger temperature produced by caffeine combined in an additive fashion with the effects produced by the stressors. Significantly greater increases in forearm blood flow and heart rate during mental arithmetic on the caffeine day suggested a potentiation of sympathetic, beta-adrenergic activity. Questionnaires administered during baseline periods to assess psychological responses to stress and caffeine revealed a potentiation of anxiety and anger responses to stress on the caffeine day.

Adolescent↗
PubMed1991

Pain sensitivity in offspring of hypertensives at rest and during baroreflex stimulation.

Healthy males with a parental history of hypertension (PH+) showed reduced pain sensitivity to a constrictive thigh-cuff pressure stimulus as compared to individuals without a parental history of hypertension. The protocol included eight trials in which a thigh-cuff was inflated until the subject reported the stimulus to be "painful." The PH+ group exhibited significantly lower pain sensitivity as indicated by (1) higher levels of constrictive pressure when pain was first reported and (2) lower subjective pain ratings at maximum constrictive pressure. To assess the role of baroreflex stimulation on pain sensitivity in these groups, four trials were administered concurrently with external carotid pressure stimulation. There were no significant differences in pain sensitivity in each group as a function of baroreflex stimulation. The results suggest that the hypoalgesia observed in hypertensives may predate the development of sustained elevations in blood pressure.

Adult↗
PubMed1991

Baroreflex sensitivity at rest and during stress in individuals with a history of vasovagal syncope.

The baroreflex sensitivity of healthy young adult males who reported some history of vasovagal syncope during emotionally stressful situations (e.g. blood donation) was compared to a control group of individuals who reported no such history. The baroreflex, which induces compensatory bradycardia and vasodilation in response to acute elevations of blood pressure, was examined as a possible mechanism underlying predisposition to vasovagal reactions. Changes in heart rate and vasoconstriction in response to baroreflex stimulation (negative external cervical pressure) at rest and during administration of a mental arithmetic task and a constrictive pain stimulus were assessed. Individuals with a history of vasovagal reactions displayed greater baroreflex sensitivity during the pain stimulus and at rest, but not during mental arithmetic. These findings suggest one mechanism of risk for syncope reactions, particularly in situations involving the experience of pain.

Adult↗
PubMed1989

Spouse and parent-offspring similarities in cardiovascular response to mental arithmetic and isometric hand-grip.

Thirty spouse pairs were recruited for a stress protocol consisting of alternating stress and relaxation periods. Repeated measurements of blood pressure, heart rate, and blood volume pulse were obtained. Spouse pairs were parents of young adult sibling pairs who had previously participated in a slightly different version of the protocol. Although spouses exhibited some behavioral similarities, there were no significant similarities in cardiovascular response to stress. However, despite the fact that parents and their offspring were tested on different occasions using somewhat different procedures, some similarities in cardiovascular reactivity were observed. Significant parent-offspring similarities in heart-rate response to mental arithmetic and diastolic blood pressure response to isometric hand-grip were observed, as well as several behavioral similarities. Assortative mating and the nature of one's current home environment seem to be less important in the familial aggregation of cardiovascular reactivity to stress than early environmental and/or genetic factors.

Adolescent↗
PubMedDate not supplied

Cardiovascular responses to occupational stress and caffeine in telemarketing employees.

Cardiovascular responses to the combination of caffeine and a challenging occupational activity were examined using a within-subject, double-blind design. Seventeen female and 11 male telemarketing employees received drinks that did and did not contain 250 mg of caffeine on two consecutive days, with order of presentation counterbalanced across subjects. Repeated measurements of systolic and diastolic blood pressure, heart rate, and digital blood volume pulse were obtained during a pre-drug resting baseline and a post-drug working period on each day. Repeated measures analyses of variance revealed significant main effects of Period on all measures of cardiovascular activity, indicating that occupational demands elicited significant cardiovascular adjustments. Only systolic blood pressure revealed a significant Drug X Period effect, indicating that responses were significantly greater on the caffeine versus placebo day. The changes in diastolic blood pressure and heart rate, although not significant, were consistent in direction with the results from previous laboratory studies. There were no significant differences between males and females in cardiovascular response to the combination of stress and caffeine.

Adult↗
PubMedDate not supplied

Similarities within young and middle-aged spouse pairs in behavioral and cardiovascular response to two experimental stressors.

The similarities of 30 young (X = 26 years) and 30 middle-aged (X = 52 years) spouse pairs in behavioral and cardiovascular response to two experimental stressors were compared to assess the importance of shared home experiences in determining cardiovascular responsivity to stress. Familial environmental influences on reactivity should produce increasing similarity among family members with number of years lived together. Although pair members exhibited a number of behavioral similarities, some of which appeared to increase with number of years lived together, there were few similarities in heart rate and blood pressure response to stress. However, both young and middle-aged pairs exhibited significant similarities in systolic blood pressure response to isometric handgrip. The fact that similarities were observed in young as well as middle-aged spouse pairs suggests that assortative mating in regards to cardiovascular reactivity to stress may occur in some instances. As a result, some previous estimates of the heritability of cardiovascular reactivity to environmental stress may have been artificially low.

Adult↗
PubMedDate not supplied

Carotid baroreflex sensitivity at rest and during psychological stress in offspring of hypertensives and non-twin sibling pairs.

The baroreceptor reflexes of 38 young adult males were mechanically stimulated by negative external cervical pressure during a mental arithmetic task and pre-stress and post-stress relaxation periods. The subjects comprised 19 pairs of non-twin siblings. Baroreflex sensitivity was significantly less pronounced during arithmetic. Using non-invasive techniques, this finding replicates several others indicating a damping of the baroreceptor reflux during stress. More importantly, analyses of sibling similarities also revealed significant familiality of baroreflex sensitivity, independent of age, body mass, pressure applied and baseline heart rate. To examine the relationship between baroreflex sensitivity and parental history of hypertension, 21 young adult males with a parental history and 25 without participated in a second experiment. The two groups were not significantly different in resting baroreflex sensitivity. However, sensitivity was damped to a significantly greater degree during mental arithmetic in offspring of hypertensives, offering one possible explanation for their greater blood pressure reactivity to stress. These results suggest that familial influences may effect baroreflex sensitivity and, possibly as a result, blood pressure reactivity and risk for hypertension.

Adult↗