Abstract
In response to central hypovolemia, triggered by lower body negative pressure (LBNP), women appeared to have lower tolerance compared to men. In addition, women exhibit blunted pressor responses to exercise compared to men, while cardiac output is increased in a similar fashion. Nonetheless, redistribution of blood flow from central to contracting muscles is required to meet higher metabolic demands during exercise in both men and women. Thus, we thought to investigate the differential effect of LBNP during exercise in men and women. PURPOSE: To determine the role of LBNP on redistributing blood flow from central to contracting muscles during moderate and high intensity exercise. METHODS: A total of 17 young men and women completed the study. Heart rate (HR) from ECG, beat to beat arterial blood pressure (BP) from Finapres, diameter, blood velocity, and flow of the brachial artery (BBF) using Doppler ultrasound on the contracting arm were continuously measured during 5 minutes of resting baseline with and without LBNP (@-20mmHg), and 5 minutes of dynamic handgrip exercise at 35% and 50% of maximal voluntary contraction (MVC) with and without LBNP. RESULTS: Compared to baseline, both men and women had a significant increase in HR and reduction in BBF to LBNP (men; 88±40@rest, 65±23@LBNP, women; 58±27@rest, 28±17@LBNP, mL/min), while mean BP did not change. During exercise at 35% and 50% MVC, women had blunted increases in BBF and mean BP. When LBNP was applied during exercise, BBF remained high to the level of exercise in both men (∆174±88@50%, ∆179±99@50%+LBNP, mL/min) and women (∆92±63@50%, ∆91±45@50%+LBNP, mL/min). CONCLUSION: Even though women exhibited lesser increase in mean BP and BBF during exercise compared to men, BBF was elevated to contracting muscles for targeted exercise intensity. LBNP does not appear to evoke redistribution of the blood flow from contracting limb regardless of sex or exercise intensity. This may be due to the pressure level of LBNP being insufficient or a higher priority in blood flow towards the contracting muscles to meet the metabolic demands.
This work is supported by National Institute of Health, National Institute of General Medical Sciences Grant (SC2GM144165 to A.K. Jensen)
Recommended Citation
Sievers, Jacob B.; Gendy, Youanaa A.; Rizk, Yusuf I.; Hernandez Valadez, Daisy; and Jensen, Areum K.
(2024)
"Does Lower Body Negative Pressure Have a Differential Effect on Blood Pressure and Blood Flow During Exercise in Women?,"
International Journal of Exercise Science: Conference Proceedings: Vol. 14:
Iss.
4, Article 33.
Available at:
https://digitalcommons.wku.edu/ijesab/vol14/iss4/33
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