Post-exercise hypotension and skeletal muscle oxygenation is regulated by nitrate-reducing activity of oral bacteria.
Free Radic Biol Med
; 143: 252-259, 2019 11 01.
Article
em En
| MEDLINE
| ID: mdl-31369841
ABSTRACT
Post-exercise hypotension (PEH) is a common physiological phenomenon leading to lower blood pressure after acute exercise, but it is not fully understood how this intriguing response occurs. This study investigated whether the nitrate-reducing activity of oral bacteria is a key mechanism to trigger PEH. Following a randomized, double blind and crossover design, twenty-three healthy individuals (15 males/8 females) completed two treadmill trials at moderate intensity. After exercise, participants rinsed their mouth with antibacterial mouthwash to inhibit the activity of oral bacteria or a placebo mouthwash. Blood pressure was measured before, 1h and 2â¯h after exercise. The microvascular response to a reactive hyperaemia test, as well as blood and salivary samples were taken before and 2â¯h after exercise to analyse nitrate and nitrite concentrations and the oral microbiome. As expected, systolic blood pressure (SBP) was lower (1â¯h -5.2⯱â¯1.0â¯mmHg; Pâ¯<â¯0.001); 2â¯h -3.8⯱â¯1.1â¯mmHg, Pâ¯=â¯0.005) after exercise compared to baseline in the placebo condition. This was accompanied by an increase of circulatory nitrite 2â¯h after exercise (2h 100⯱â¯13â¯nM) compared to baseline (59⯱â¯9â¯nM; Pâ¯=â¯0.013). Additionally, an increase in the peak of the tissue oxygenation index (TOI) during the reactive hyperaemia response was observed after exercise (86.1⯱â¯0.6%) compared to baseline levels (84.8⯱â¯0.5%; Pâ¯=â¯0.010) in the placebo condition. On the other hand, the SBP-lowering effect of exercise was attenuated by 61% at 1â¯h in the recovery period, and it was fully attenuated 2â¯h after exercise with antibacterial mouthwash. This was associated with a lack of changes in circulatory nitrite (Pâ¯>â¯0.05), and impaired microvascular response (peak TOI baseline 85.1⯱â¯3.1%; peak TOI post-exercise 84.6⯱â¯3.2%; Pâ¯>â¯0.05). Diversity of oral bacteria did not change after exercise in any treatment. These findings show that nitrite synthesis by oral commensal bacteria is a key mechanism to induce the vascular response to exercise over the first period of recovery thereby promoting lower blood pressure and greater muscle oxygenation.
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Base de dados:
MEDLINE
Assunto principal:
Bactérias
/
Exercício Físico
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Músculo Esquelético
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Hipotensão Pós-Exercício
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Hiperemia
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Boca
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Nitratos
Idioma:
En
Ano de publicação:
2019
Tipo de documento:
Article