Effects of Mild Voluntary Hypoventilation During Progressive Interval Training on Cardiorespiratory Fitness in Recreational Mountaineers: A Clinical Trial
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 发起方
- 入组人数
- 24
- 试验地点
- 1
- 主要终点
- Resting Heart Rate
研究概览
简要总结
This study investigated whether adding structured breath-holds to standard interval training improves cardiorespiratory fitness in recreational mountaineers more than interval training alone. Twenty-four male recreational mountaineers participated in an 8-week progressive treadmill interval training program. Participants were divided into two groups: a controlled-breathing group that performed structured mid-tidal breath-holds during training, and a free-breathing group that maintained unrestricted breathing. The primary outcomes measured were resting heart rate and estimated maximal oxygen uptake, along with secondary measures including blood pressure and pulmonary function indices. The study aimed to determine if this mild voluntary hypoventilation technique provides additional physiological benefits for altitude preparation.
详细描述
Recreational mountaineers often train at low altitudes without access to specialized hypoxic facilities. While intermittent hypoxic training is an established preparation strategy, the required equipment is costly and inaccessible. Voluntary hypoventilation training (VHT), which involves deliberate breath-holds during exercise, has been proposed as a low-cost alternative. However, its efficacy at producing mild desaturation levels suitable for recreational settings had not been established.
This retrospective clinical trial evaluated the effects of mild VHT on cardiorespiratory fitness. Twenty-four male recreational mountaineers completed a progressive 8-week treadmill interval training program (24 sessions, 65-85% heart rate reserve) between September and November 2023. Participants were allocated to either a controlled-breathing (CB) group or a free-breathing (FB) group. The CB group performed structured mid-tidal breath-holds synchronized to an electronic metronome during approximately 25% of the main training phase, targeting a peripheral oxygen saturation (SpO₂) nadir of 92-94%. The FB group completed the identical exercise protocol with unrestricted breathing, maintaining SpO₂ at or above 97%.
Physiological assessments were conducted at baseline and within 48 hours post-intervention. Measurements included resting cardiovascular parameters (heart rate and blood pressure), estimated maximal oxygen uptake (VO₂max) via a modified Bruce treadmill protocol, and comprehensive pulmonary function testing (spirometry). Continuous SpO₂ monitoring was utilized during all training sessions to ensure protocol adherence and participant safety.
研究设计
- 研究类型
- Interventional
- 分配方式
- Non Randomized
- 干预模型
- Parallel
- 主要目的
- Other
- 盲法
- Single (Outcomes Assessor)
盲法说明
Participants and training supervisors were unblinded to the breathing intervention. The technician conducting spirometry assessments was blinded to group allocation.
入排标准
- 年龄范围
- 25 Years 至 35 Years（Adult）
- 性别
- Male
- 接受健康志愿者
- 是
入选标准
- •Male recreational mountaineers aged 25 to 35 years.
- •A minimum of 6 months of mountaineering experience with at least 3 sessions per month.
- •Willingness to attend at least 85% of the scheduled training sessions.
- •Negative responses to all items on the Physical Activity Readiness Questionnaire (PAR-Q).
排除标准
- •Diagnosed cardiovascular, respiratory, or musculoskeletal disorders.
- •Current smoking.
- •Use of medications affecting heart rate or blood pressure.
- •Prior experience with structured hypoxic or breath-hold training.
研究组 & 干预措施
Free-Breathing (FB) Group
Participants completed the identical 24 supervised treadmill interval sessions over 8 weeks (65-85% heart rate reserve) with unrestricted breathing throughout all sessions. Continuous SpO₂ monitoring confirmed values remained at or above 97%.
干预措施: Progressive Treadmill Interval Training (Behavioral)
Controlled-Breathing (CB) Group
Participants completed 24 supervised treadmill interval sessions over 8 weeks (65-85% heart rate reserve). During approximately 25% of the main training phase, participants performed structured mid-tidal breath-holds synchronized to an electronic metronome (progressing from 3-count to 6-count cycles), targeting a peripheral oxygen saturation (SpO₂) nadir of 92-94%.
干预措施: Voluntary Hypoventilation Training (Behavioral)
Controlled-Breathing (CB) Group
Participants completed 24 supervised treadmill interval sessions over 8 weeks (65-85% heart rate reserve). During approximately 25% of the main training phase, participants performed structured mid-tidal breath-holds synchronized to an electronic metronome (progressing from 3-count to 6-count cycles), targeting a peripheral oxygen saturation (SpO₂) nadir of 92-94%.
干预措施: Progressive Treadmill Interval Training (Behavioral)
结局指标
主要结局
Resting Heart Rate
时间窗: Baseline (within 48 hours before the first training session) and post-intervention (within 48 hours after the final 8-week training session).
Resting heart rate (beats per minute) recorded using a 12-lead electrocardiograph after 10 minutes of seated rest in a quiet, temperature-controlled room. The mean value from the final 2 minutes is used for analysis.
Estimated Maximal Oxygen Uptake (VO2max)
时间窗: Baseline (within 48 hours before the first training session) and post-intervention (within 48 hours after the final 8-week training session).
Estimated VO2max (mL·kg-¹·min-¹) determined using a modified Bruce treadmill protocol until volitional exhaustion. It is calculated from total treadmill time (in minutes) using the Foster equation.
次要结局
- Systolic Blood Pressure(Baseline and post-intervention (within 48 hours after the final 8-week training session).)
- Diastolic Blood Pressure(Baseline and post-intervention (within 48 hours after the final 8-week training session).)
- Tidal Volume (TV)(Baseline and post-intervention (within 48 hours after the final 8-week training session).)
- Vital Capacity (VC)(Baseline and post-intervention (within 48 hours after the final 8-week training session).)
- Forced Vital Capacity (FVC)(Baseline and post-intervention (within 48 hours after the final 8-week training session).)
- Forced Expiratory Volume in 1 Second (FEV1)(Baseline and post-intervention (within 48 hours after the final 8-week training session).)
- Peak Expiratory Flow (PEF)(Baseline and post-intervention (within 48 hours after the final 8-week training session).)
- Forced Expiratory Flow at 25-75% of FVC (FEF25-75%)(Baseline and post-intervention (within 48 hours after the final 8-week training session).)
- Maximum Voluntary Ventilation (MVV)(Baseline and post-intervention (within 48 hours after the final 8-week training session).)
研究者
Mohammadreza Rezaeipour, MD, PhD
Assoc. Prof. Dr.
University of Sistan and Baluchestan