Influence of Sex Difference and Oral Contraceptives on Forearm Reactive Hyperemia

Abstract

Experiments were performed on normal male and female subjects to compare blood flow responses following release of an arterial occlusion (reactive hyperemia). Additionally, the effects of oral contraceptive therapy on the reactive hyperemia reaction were studied in female subjects. Forearm blood flow was measured with a strain-gauge plethysmograph, heart rate with an electrocardiograph, and mean arterial pressure was measured by auscultation. Blood flow was determined before and after circulatory arrest of 1, 3, and 5 min. Blood serum levels of 17β-estradiol, progesterone, luteinizing hormone (LH), and follicle stimulating hormone (FSH) were measured by radioimmunoassay. The mean resting forearm blood flow was similar in males and females (∼4 ml/100 ml/min). There were no significant changes in systemic mean arterial pressure or heart rate during the experiments. Following 1 min of arterial occlusion, the peak blood flow responses were similar in males and females. The peak blood flow responses following release of arterial occlusion were lower in males than in untreated females at occlusion intervals of 3 and 5 min. Females receiving oral contraceptives showed reduced peak blood flow responses after circulatory arrest of either 3 or 5 min as compared to untreated females. There were no significant differences in the recovery times of the hyperemic responses between males and females following any of the periods of occlusion. The peak blood flow responses following 3 min of arterial occlusion were significantly correlated with the blood serum levels of 17β-estradiol, LH and FSH, but not with the blood serum levels of progesterone. These results suggest that: (1) sex difference has a marked effect on the blood flow response following arterial occlusion, and (2) hormonal changes influence vascular responsiveness in the female.

Age‐related microvascular dysfunction: novel insight from near‐infrared spectroscopy

“…This will need to be accounted for if this methodology is going to be adopted widely, especially in clinical populations. Although we did not specifically control for menstrual cycle in our young female participants, which can affect vascular reactivity (Webb et al 1981), we do not believe this affected our interpretation of the present results given the fact that all age-related differences disappeared when we controlled for tissue ischaemia. Finally, our elderly group consisted of only 10 relatively healthy seniors in the seventh decade of life.…”

Sex differences in control of cutaneous blood flow.

“…This observation parallels that made in the forearm, in which hyperemic blood flow is greater in women. 20 Thus, maximal blood flow in both the cutaneous and muscular circulations of the upper extremity appears to be greater in women.…”

Reactive hyperemia: a review of methods, mechanisms, and considerations

“…1), and there has been continued interest in this approach (23,31,38). Indeed, measurement of RH by venous occlusion plethysmography has been shown to be prognostically significant (68) and capable of differentiating experimental conditions and clinical phenotypes (40,97,110,112,115). Measurement of RH by venous occlusion plethysmography is commonly reported in two ways: 1) peak forearm blood flow (FBF) (7,23,35,50,81,104), measured as the highest FBF detected during the hyperemic response, and 2) total FBF, measured as the area under the FBF curve throughout the hyperemic response and recovery toward baseline blood flow (7,23,35,38,81,104).…”