Oral Nitrite Synthesis and Post-exercise Hypotension

The Impact of Nitrate-reducing Capacity of Oral Bacteria on Post-exercise Hypotension in Healthy Individuals.

Exercise is probably the most effective approach to reduce blood pressure. In fact, a single bout of exercise induces a physiological response known as Post-Exercise Hypotension (PEH) where a prolonged decrease in resting blood pressure occurs in the minutes and hours after exercise. However, it is not fully understood how this response triggers. Recent evidence suggests that oral bacteria may play a key role in blood pressure control by enhancing nitrite, and then nitric oxide (NO) bioavailability under resting conditions in humans. However, no previous study has investigated whether this is a key mechanism involve in PEH. Thus, the main aim of this study was to investigate if the oral nitrate/nitrite pathway is a key regulator of PEH and vasodilation in healthy humans.

Study Overview

• Status: Completed
• Conditions: Blood Pressure; Sports Physical Therapy
• Intervention / Treatment: Other: Exercise

• Study Type: Interventional
• Enrollment (Actual): 23
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • Devon
    • Plymouth, Devon, United Kingdom, PL4 8AA
      • Laboratory of Nutrition, Exercise & Health

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 50 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

Blood pressure (SBP < 130 mmHg; DBP < 90 mmHg) BMI < 30 kg/m2 Age 18 to 50 years old

Exclusion Criteria:

Smoker Hypertension Dyslipidaemia Diabetes Gingivitis or periodontitis Using antibacterial mouthwash or tongue scrapes Taking antibiotics 1 month before the start of the study Females without have irregular menstrual periods

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Placebo Mouthwash	Other: Exercise; Four sets of 7 minutes at 65% of VO2peak interspersed with 3 min of passive recovery
Active Comparator: Antibacterial Mouthwash	Other: Exercise; Four sets of 7 minutes at 65% of VO2peak interspersed with 3 min of passive recovery

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in blood pressure after exercise	Blood pressure was measured before and at 1 hour and 2hours after exercise using an electronic sphygmomanometer (ProBP 3400, Welch Allyn). The second and third readings will be averaged to determine mean blood pressure.	Baseline and 1 hour and 2 hours after exercise

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in reactive hyperaemia	Tissue oxygenation index (TOI) were recorded on the left forearm (extensor digitorum) using a NIRS system (NIRO-200NX, Hamamatsu) before exercise and 2 hours after exercise. After baseline measurements (2 minutes), an automatic pneumatic cuff (Hokanson E-20 AG101) was inflated ~5cm above the elbow for 5 minutes to an occlusion pressure of 200 mmHg. Then, inflation of the cuff was rapidly released (< 1 second) and the NIRS measurements were continuously monitored for 5 minutes.	Baseline and 1 hour and 2 hours after exercise

Collaborators and Investigators

• Sponsor: University of Plymouth
• Investigators: Principal Investigator: Crai Cutler, MSc, University of Plymouth

Study record dates

Study Major Dates

• Study Start (Actual): May 9, 2017
• Primary Completion (Actual): April 20, 2018
• Study Completion (Actual): March 11, 2019

Study Registration Dates

• First Submitted: April 3, 2019
• First Submitted That Met QC Criteria: April 3, 2019
• First Posted (Actual): April 5, 2019

Study Record Updates

• Last Update Posted (Actual): April 8, 2019
• Last Update Submitted That Met QC Criteria: April 4, 2019
• Last Verified: April 1, 2019

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Nervous System Diseases; Autonomic Nervous System Diseases; Primary Dysautonomias; Orthostatic Intolerance; Hypotension; Post-Exercise Hypotension
• Other Study ID Numbers: (16/17)-666

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: Information will be available upon request

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No