Exercise Timing on the Morning Blood Pressure Surge

The Effects of Morning vs. Evening High-intensity Interval Exercise on the Magnitude of the Morning Blood Pressure Surge

The goal of this clinical trial was to assess the effects of morning vs. evening high-intensity interval exercise on the magnitude of the morning blood pressure surge in young healthy adults. The main questions it aimed to answer were:

• Does the timing of high-intensity interval exercise modulate the magnitude of the morning blood pressure surge?
• Do sex differences exist?

Participants came in and completed a bout of high-intensity interval exercise in the morning (8-10 am) and evening (5-7 pm) as well as a no exercise control, and ambulatory blood pressure was assessed for 24 hours afterwards.

Study Overview

• Status: Completed
• Conditions: Post-Exercise Hypotension; Ambulatory Blood Pressure Monitoring; High-intensity Interval Exercise
• Intervention / Treatment: Other: Morning high-intensity interval exercise; Other: Evening high-intensity interval exercise

Detailed Description

Introductory Visit:

Participants came in for 4 visits. The first visit was an introductory visit where chronotype, eligibility for exercise, and anthropometrics were measured. This was followed by a maximal incremental exercise test to determine aerobic capacity (i.e., V̇O2peak) on a cycle ergometer, and instrumentation of an ambulatory blood pressure monitor for familiarization during daily activities and sleep.

Intervention Visits:

Three intervention visits (control, morning exercise, and evening exercise) were completed. The order was randomized using and each visit was separated by a minimum of 36 hours. Each intervention visit began by obtaining the participant's resting blood pressure and heart rate and ended with the instrumentation of the ambulatory blood pressure monitor. No exercise was performed during the control visit. The morning exercise visit included a bout of high-intensity interval exercise between 8-10 am and the evening exercise visit included a bout of high-intensity interval exercise between 5-7 pm. The high-intensity interval exercise protocol consisted of a light intensity, 3-minute warm-up at 15% peak power followed by ten 1-minute work intervals at 80% of peak power, with each interval separated by 1-minute rest intervals at 15% peak power. A 3-minute cool down was performed at 15% peak power.

• Study Type: Interventional
• Enrollment (Actual): 31
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Canada
  • Ontario
    • Guelph, Ontario, Canada, N1G 2W1
      • University of Guelph

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion:

• Between 18-50 years of age.
• No history of known disease.
• None smokers.
• No use of chronic medications other than oral contraceptives.

Exclusion:

• <18 years of age.
• >50 years of age.
• Cardiovascular disease.
• Metabolic disease.
• History of smoking (within the past 3 months).
• Chronic medications (other than oral contraceptives).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Control; No exercise was performed and ambulatory blood pressure was assessed for 24 hours.
Experimental: Morning high-intensity interval exercise; High-intensity interval exercise was performed between 8-10 am and ambulatory blood pressure was assessed for 24 hours after.	Other: Morning high-intensity interval exercise; High-intensity interval exercise was performed between 8-10 am
Experimental: Evening high-intensity interval exercise; High-intensity interval exercise was performed between 5-7 pm and ambulatory blood pressure was assessed for 24 hours after.	Other: Evening high-intensity interval exercise; High-intensity interval exercise was performed between 5-7 pm

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Morning blood pressure surge	The difference between morning blood pressure (the mean of the 4 blood pressure readings after awakening) and sleep-trough blood pressure (the mean of the lowest blood pressure during sleep and two adjacent blood pressure readings).	Through study completion, an average of 4 weeks.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Nighttime blood pressure dip	The percent difference between daytime blood pressure (average of all blood pressure readings when participants reported being awake) and nighttime blood pressure (average of all blood pressure readings when the participant reported being asleep).	Through study completion, an average of 4 weeks.

Collaborators and Investigators

• Sponsor: University of Guelph
• Investigators: Principal Investigator: Philip Millar, PhD, University of Guelph; Study Director: Julian Bommarito, MSc, University of Guelph

Study record dates

Study Major Dates

• Study Start (Actual): January 28, 2020
• Primary Completion (Actual): June 8, 2023
• Study Completion (Actual): June 8, 2023

Study Registration Dates

• First Submitted: November 19, 2024
• First Submitted That Met QC Criteria: November 21, 2024
• First Posted (Actual): November 25, 2024

Study Record Updates

• Last Update Posted (Estimated): November 27, 2024
• Last Update Submitted That Met QC Criteria: November 24, 2024
• Last Verified: November 1, 2024

More Information

Terms related to this study

• Keywords: Ambulatory blood pressure monitoring; Post-exercise hypotension; High-intensity interval exercise; Morning blood pressure surge
• Additional Relevant MeSH Terms: Nervous System Diseases; Vascular Diseases; Cardiovascular Diseases; Primary Dysautonomias; Autonomic Nervous System Diseases; Orthostatic Intolerance; Hypotension; Post-Exercise Hypotension
• Other Study ID Numbers: 19-07-002

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Individual participant data that underlie the results reported in this article, after deidentification (text, tables, figures, and appendices).
• IPD Sharing Time Frame: After publication; unending.
• IPD Sharing Access Criteria: Investigators whose proposed use of the data has been approved by an independent review committee ("learned intermediary") identified for this purpose.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL

Drug and device information, study documents

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