Breathing Protocol in Breath-hold Divers

Study Overview
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Brief Summary
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The aim of this randomized controlled trial study was to assess the effects of an 4-week exercise program on the recovery capacity after a voluntary maximal apnea. Participants will be randomly allocated to perform an experimental breathing protocol (NR-HB), or an usual training using their usual breathing (UB) protocol.

Detailed Description
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It is a multi-center study. 2 different Spanish Freedivers Centres are included in the study (Madrid and Zaragoza). Divers were randomly assigned to receive an experimental training (NR-HB) or to be included in the Control Group (UB). The trial included two study visits. Each exercise training program will be applied sessions per week during 4 weeks. Participants received baseline assessments at the beginning of any intervention, and post-intervention assessments at the end of the fourth week.

Official Title
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Breathing Protocol on Oxygen Saturation Recovery After a Dynamic Apnoea in Breath-hold Divers: a Single-blind, Randomized Clinical Trial

Conditions
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Exercise Training, Apnea, Breathholding, Breathing Exercises

Intervention / Treatment
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* Other: hook breathing removing nose-clip
* Other: usual breathing (UB)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Absence of pain or illness No changes in cognitive ability Over 18 years old. Member of the Spanish Federation of Underwater Activities. Positive medical examination that allows the diver to practice voluntary apnea. Exclusion Criteria: People with systemic diseases, tumors, infections, pacemakers, history of epilepsy, hydrophobia, pregnancy women, pharmacological treatment. To be participating in other physical activities during the experimental research

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: parallel-group
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: hook breathing removing nose-clip<br>It will apply a usual training program for 4 weeks, 4hours and 30 min per week distributed equally over 3 days in the week. In each session, it was performed 8 submaximes-dynamic apnoeas with 3-minute recovery between each one. Then was performed a maximal-dynamic apnoea. To finish the session, was performed a continuous training of free style swimming at moderate effort over 30 minutes. During that training, only this group will perform an experimental breathing protocol consisted of removing nose-clip previous to surface and then perform hook breathing during 20 seconds. This protocol was applied at the end of each of the 8 submaximes-dynamic apnoeas and after the maximal-dynamic apnoea | Other: hook breathing removing nose-clip<br>* Participants will perform 3 days per week of usual training, involving intense exercise 8 submaximes-dynamic apnoeas with 3-minute recovery between each one per session, and continuous training of free style swimming at moderate effort over 30 minutes, including warm-up, recovery between intervals and cool down. The experimental breathing protocol consisted on to remove nose-clip previous to surface and then perform hook breathing during 20 seconds.<br>|
| Active Comparator: usual breathing (UB)<br>It will apply a usual training program for 4 weeks, 4hours and 30 min per week distributed equally over 3 days in the week. In each session, it was performed 8 submaximes-dynamic apnoeas with 3-minute recovery between each one. Then was performed a maximal-dynamic apnoea. To finish the session, was performed a continuous training of free style swimming at moderate effort over 30 minutes. | Other: usual breathing (UB)<br>* Participants will perform 3 days per week of usual training, involving intense exercise 8 submaximes-dynamic apnoeas with 3-minute recovery between each one per session, and continuous training of free style swimming at moderate effort over 30 minutes, including warm-up, recovery between intervals and cool down.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Oxygen Saturation change | Oxygen Saturation recovery will be record by the experimenters every 5 seconds by a handheld pulse-oximeter during the 1 min recovery time after a maximal dynamic apnea. The outcome was the length of the time to return to 95% SpO2 during the 1 min recovery time after maximal dynamic apnoea | Before and after training intervention (after 4 weeks) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Heart Rate recovery | Heart Rate will be record by the experimenters every 5 seconds by a handheld pulse-oximeter during the 1 min recovery time after a maximal dynamic apnea. The outcome was the length of the time to stabilize heart rate during these 1 minute. | before and after training intervention (after 4 weeks) | 
| Lung function (forced spirometry) | The Spirometry will be perform according to American Thoracic Society criteria and was measured in litres. The maneuver will be perform 3 times and recording the best one. | before and after training intervention (after 4 weeks) |