Ascorbic acid attenuates the pressor response to voluntary apnea in postmenopausal women

Brittney J. Randolph, Hardikkumar M. Patel, Matthew D. Muller

Research output: Contribution to journalArticle

Abstract

We recently demonstrated that postmenopausal women have an augmented blood pressure response to voluntary apnea compared to premenopausal women. Both obstructive sleep apnea (OSA) and healthy aging are associated with increased oxidative stress, which may impair cardiovascular function. Restoring physiological responses could have clinical relevance since transient surges in blood pressure are thought to be an important stimulus for endorgan damage in aging and disease. We tested the hypothesis that acute antioxidant infusion improves physiological responses to voluntary apnea in healthy postmenopausal women (n = 8, 64 ± 2 year). We measured beat-bybeat mean arterial pressure (MAP), heart rate (HR), and brachial artery blood flow velocity (BBFV, Doppler ultrasound) following intravenous infusion of normal saline and ascorbic acid (~3500 mg). Subjects performed maximal voluntary end-expiratory apneas and changes (Δ) from baseline were compared between infusions. The breath hold duration and oxygen saturation nadir were similar between saline (29 ± 6 sec, 94 ± 1%) and ascorbic acid (29 ± 5 sec, 94 ± 1%). Ascorbic acid attenuated the pressor response to voluntary apnea (ΔMAP: 6 ± 2 mmHg) as compared to saline (ΔMAP: 12 ± 2 mmHg, P = 0.034) and also attenuated forearm vasoconstriction (ΔBBFV: 4 ± 9 vs. –12 ± 7%, P = 0.049) but did not affect ΔHR. We conclude that ascorbic acid lowers the blood pressure response to voluntary apnea in postmenopausal women by inhibiting vasoconstriction in the limb vasculature. Whether ascorbic acid has similar effects in OSA patients remains to be prospectively tested.

Original languageEnglish (US)
Article numbere12384
JournalPhysiological reports
Volume3
Issue number4
DOIs
StatePublished - Jan 1 2015

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Apnea
Ascorbic Acid
Arterial Pressure
Obstructive Sleep Apnea
Blood Pressure
Vasoconstriction
Heart Rate
Doppler Ultrasonography
Brachial Artery
Blood Flow Velocity
Intravenous Infusions
Forearm
Oxidative Stress
Extremities
Antioxidants
Oxygen

All Science Journal Classification (ASJC) codes

  • Physiology
  • Physiology (medical)

Cite this

Randolph, Brittney J. ; Patel, Hardikkumar M. ; Muller, Matthew D. / Ascorbic acid attenuates the pressor response to voluntary apnea in postmenopausal women. In: Physiological reports. 2015 ; Vol. 3, No. 4.
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Ascorbic acid attenuates the pressor response to voluntary apnea in postmenopausal women. / Randolph, Brittney J.; Patel, Hardikkumar M.; Muller, Matthew D.

In: Physiological reports, Vol. 3, No. 4, e12384, 01.01.2015.

Research output: Contribution to journalArticle

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