Format

Send to

Choose Destination
Microcirculation. 2018 Dec 26:e12525. doi: 10.1111/micc.12525. [Epub ahead of print]

Dietary nitrate improves muscle microvascular reactivity and lowers blood pressure at rest and during isometric exercise in untreated hypertensives.

Author information

1
Laboratory of Exercise Physiology and Biochemistry, Department of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Serres, Greece.
2
Third Department of Internal Medicine, Papageorgiou Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece.
3
Cytology Department, Theagenio Cancer Hospital, Thessaloniki, Greece.

Abstract

OBJECTIVE:

This double-blind, cross-over study examined in drug-naïve hypertensives the effects of a single dose of dietary nitrate (beetroot juice, BRJ) on (a) office/ambulatory BP and arterial stiffness, (b) muscle microvascular function, and (c) hemodynamic responses and cardiovagal baroreceptor sensitivity (cBRS) at rest and during isometric exercise.

METHODS:

Eighteen untreated hypertensives (44.0 ± 2.6 years) consumed randomly, a nitrate-rich (8.1 mmol-BRJnitrate ) and a nitrate-depleted (BRJplacebo ) BRJ. Office BP and pulse wave velocity were assessed before/after BRJ. An occlusion-reperfusion maneuver with continuous monitoring of muscle oxygenated hemoglobin (O2 Hb) and total hemoglobin (tHb), via NIRS, followed. Participants performed submaximal isometric handgrip with beat-by-beat monitoring of hemodynamics and cBRS. Ambulatory BP assessment followed.

RESULTS:

During reperfusion, following arterial occlusion, the magnitude and rate of muscle microvascular reoxygenation (O2 Hb) and red blood cell content (tHb) were higher in BRJnitrate vs BRJplacebo (P < 0.05), suggesting improved microvascular reactivity. Office/ambulatory BP were lower following BRJnitrate vs BRJplacebo (P < 0.05); pulse-wave-velocity was not altered. During isometric handgrip, BP and peripheral resistance rise were smaller in BRJnitrate vs BRJplacebo (P < 0.01-0.05), with no differences in cBRS.

CONCLUSIONS:

In drug-naïve hypertensives, a single dose of BRJ induces (a) short-term reductions in resting/ambulatory BP, (b) acute improvements in muscle microvascular function, and (c) attenuation in BP and peripheral resistance responses during isometric exercise.

KEYWORDS:

baroreceptor sensitivity; beetroot; blood pressure; dietary nitrate; exercise; hypertension; isometric; microcirculation; microvascular; pulse wave velocity

PMID:
30586209
DOI:
10.1111/micc.12525

Supplemental Content

Full text links

Icon for Wiley
Loading ...
Support Center