Effects of Static Apnea at High Lung Volume on Hypoalgesia, Cardiovascular Function and Respiratory Function

Study Overview
=================
Brief Summary
-----------------
The aim of this randomized controlled study is to explore the hypoalgesic response of a 6 minutes of intermittent static apneas training session at high lung volume in healthy subjects; also, as secondary objectives, to analyze the cardiovascular and respiratory response produced during the intervention.

Official Title
-----------------
Effects of Static Apnea at High Lung Volume on Hypoalgesia, Cardiovascular Function and Respiratory Function

Conditions
-----------------
Pain, Hypoxia, Hypercapnia, Apnea

Intervention / Treatment
-----------------
* Other: Voluntary apnoea


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: - Asymptomatic subjects aged between 18 and 64 years. Exclusion Criteria: Cardiovascular, respiratory, metabolic, neurological or osteomuscular signs or pathologies. History of epilepsy. Pregnant. Pharmacological treatment. Participants who present any type of pain on the day of the measurements or who have frequently suffered pain during the previous 4 weeks.

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Static apnea at High Lung Volume<br>Participants will remain at rest in the supine position for 6 minutes. Participants in the experimental group will perform intermittent apneas at high lung volume with a density of 30 seconds, followed by a normal breath of 10 seconds (9 cycles of 30s apnea - 10s normal breathing, until completing the 6 minutes). | Other: Voluntary apnoea<br>* Static apneas at high lung volume with a density of 30 seconds, followed by a normal breath of 10 seconds (9 cycles of 30s apnea - 10s normal breathing, until completing the 6 minutes).<br>|
| No Intervention: Static at normal breathing<br>Participants will remain at rest in the supine position for 6 minutes. Participants in the control group will remain breathing normally for these 6 minutes | |

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pain pressure threshold (PPT) on thumb, anterior tibial and spinous process of C7 | PPT is tested on the dorsal base of the distal phalanx of the thumb on the dominant side and on the muscle belly of the tibialis anterior on the dominant side. The region to be pressed is marked with a pen. The patient is instructed to report with the first appearance of the sensation of discomfort. An ascending ramp of 0.5 kg/cm/s is applied, at the rhythm of a metronome. The measurement is started on the thumb, and alternated with tibia and C7 until 3 measurements of each region are obtained, enough time to give 30 seconds of rest between measurements in the same region. This protocol has demonstrated high inter-observer reliability measuring healthy subjects (ICC = 0.91). | before and after intervention (up 30 minutes) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Perceived Stress Scale (PSS) | 14-item questionnaire about their thoughts and feelings in the last month. The scale has a range of scores from 0 to 56. The lower the score, the more favorable for the patient's health. | before intervention (up 5 minutes) | 
| Pittsburg Sleep Quality Index (PSQI) | 9-item questionnaire on sleep quality in the past month. The scale has a range of scores from 0 to 21. The lower the score, the more favorable for the patient's health. | before intervention (up 5 minutes) | 
| Global Physical Activity Questionnaire (GPAQ) | 6-item questionnaire on the level of physical activity at work, for commuting and in leisure time. A higher score means higher weekly physical activity | before intervention (up 5 minutes) | 
| Oxygen saturation | Oxygen saturation will be measured during the procedure by finger pulse oximetry. | during intervention (up 6 minutes) | 
| Heart rate | Heart rate will be measured during the procedure by finger pulse oximetry. | during intervention (up 6 minutes) | 
| Blood pressure | Systolic and diastolic blood pressure will be measured before, during and immediately after the procedure using a digital wrist sphygmomanometer. | before, during and after intervention (up 10 minutes) | 
| Rate of perceived exertion (RPE) | RPE Borg CR-10 is used to measure how hard your body works during physical activity. It runs from 0 - 10, using numbers to rate how much effort an activity takes. | immediately after intervention (up 10 seconds) |