Respiratory Muscle Training and Intermittent Hypoxia: Additive Health Effects?

Acute Effects of Intermittent Respiratory Muscle Training and Hypoxia on Cardiovascular and Sleep Parameters in Elderly Persons With Prehypertension

The prevalence of pre-hypertension and hypertension in the elderly is very high. Apart from medication, physical exercise training is a potential strategy to reduce blood pressure, however, the ability to perform exercise can be limited in the elderly. Hence, alternative non-pharmacological strategies to reduce blood pressure are necessary. Two interventions that have been shown to positively influence blood pressure are respiratory muscle training (RMT) and intermittent hypoxia (IH). Whether a combination of RMT and IH yields even better effects is currently unknown. Therefore, in this study, the effect of a single session of RMT with and without IH on blood pressure and associated cardiovascular parameters will be investigated in elderly subjects with pre-hypertension.

Study Overview

• Status: Completed
• Conditions: Pre-Hypertension
• Intervention / Treatment: Procedure: RMT; Procedure: RMT + IH; Procedure: Control

• Study Type: Interventional
• Enrollment (Actual): 14
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Switzerland
  • ZH
    • Zurich, ZH, Switzerland, 8057
      • Exercise Physiology Lab, Institute of Human Movement Sciences and Sport, ETH Zurich

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 65 years to 80 years (OLDER_ADULT)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Age: 65-80 years
• Systolic blood pressure between 130-139 mmHg and diastolic blood pressure lower than 90 mmHg
• Non smoking
• Normal Body-Mass-Index (BMI): 18.5-24.9 kg·m-2
• Normal Lung Function
• Willing to adhere to the general study rules

Exclusion Criteria:

• Known or suspected non-compliance, drug or alcohol abuse
• Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, dementia, etc. of the participant
• Previous enrolment into the current study
• Enrolment of the investigator, his/her family members, employees and other dependent persons
• Intake of blood pressure medication
• Intake of medications affecting sleep or the performance or the respiratory, cardiovascular or neuromuscular system
• Acute or chronic illness other than prehypertension

Study Plan

How is the study designed?

Design Details

• Primary Purpose: TREATMENT
• Allocation: NA
• Interventional Model: SINGLE_GROUP
• Masking: NONE

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
EXPERIMENTAL: Study Group	Procedure: RMT; RMT consists of six bouts of 5-min of volitional hyperpnoea . After each RMT bout, participants will breathe room air for 5 minutes.; Procedure: RMT + IH; RMT and IH consist of six bouts of 5-min of volitional hyperpnoea. After each RMT bout, participants will breathe a hypoxic gas mixture (10.5% O2 ) for 5 minutes.; Procedure: Control; No intervention

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in blood pressure in mmHg	Blood pressure before, during, and after each intervention measured with an automated sphygmomanometer	At baseline after 20 min of lying in a supine position, every 5 minutes during the 60 min intervention, and 20, 35 and 50 min after the end of the intervention

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in pulse wave velocity in m/s	Carotid-femoral pulse wave velocity before and after each intervention, assessed with a device that simultaneously records (non-invasively) pressure signals from the carotid and femoral arteries	At baseline after 25 min of lying in a supine position, and 25, 40 and 55 min after the end of the intervention
Change in cardiac output in L/min	Cardiac output before, during, and after each intervention measured with impedance cardiography	At baseline after 15min of lying in a supine position, every 5 minutes during the 60 min intervention, and 15, 30 and 45 min after the end of the intervention
Change in total peripheral resistance in dyn x s/cm^5	Total peripheral resistance before, during, and after each intervention measured with impedance cardiography	At baseline after 15min of lying in a supine position, every 5 minutes during the 60 min intervention, and 15, 30 and 45 min after the end of the intervention
Changes in baroreflex sensitivity in ms/mmHg	Baroreflex sensitivity before and after each intervention assessed with photo plethysmography	At baseline after 15min of lying in a supine position, and 15, 30 and 45 min after the end of the intervention
Change in heart rate variability in ms	Heart rate variability measured before, during and after each intervention with impedance cardiography	At baseline after 15min of lying in a supine position, every 5 minutes during the 60 min intervention, and 15, 30 and 45 min after the end of the intervention
Change in peripheral oxygenation during sleep in %Saturation	Peripheral oxygenation during sleep measured at home after each intervention with a finger pulse oxymeter	Continuously during the night following each intervention, from time to bed until wake up time in the morning (i.e. on average approximately 8hours)
Change in sleep efficiency defined as the ratio of total sleep time and time in bed	Sleep efficiency measured at home after each intervention with an actigraph	Continuously during the night following each intervention, from time to bed until wake up time in the morning (i.e. on average approximately 8hours)
Change in subjective sleep quality	Sleep quality (i.e. "How well did you sleep?" and "How recovered are you?") measured at home after each intervention with a visual analog scale (VAS). The two VAS consists each of a 10cm-horizontal line, with the left end of the lines representing low sleep quality ("slept very badly" and "not recovered at all", respectively) and the right end representing good sleep quality ("slept very well" and "completely recovered", respectively). Participants are asked to draw a vertical line in between the two ends on each of the two VAS.	Within 5 minutes after waking-up following the night after each intervention

Collaborators and Investigators

• Sponsor: Swiss Federal Institute of Technology

Study record dates

Study Major Dates

• Study Start (ACTUAL): September 29, 2017
• Primary Completion (ACTUAL): July 4, 2018
• Study Completion (ACTUAL): July 4, 2018

Study Registration Dates

• First Submitted: October 4, 2017
• First Submitted That Met QC Criteria: October 17, 2017
• First Posted (ACTUAL): October 18, 2017

Study Record Updates

• Last Update Posted (ACTUAL): August 15, 2018
• Last Update Submitted That Met QC Criteria: August 14, 2018
• Last Verified: August 1, 2018

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Signs and Symptoms, Respiratory; Prehypertension; Hypoxia
• Other Study ID Numbers: REHYPE_2017

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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