Sleep Disordered Breathing During Live High-Train Low in Normobaric Versus Hypobaric Hypoxia

Area of Science:

• Sports Science
• Altitude Training
• Sleep Medicine

Background:

• Live high-train low (LHTL) is a training strategy used by athletes to enhance performance.
• Understanding the physiological effects of different hypoxia types during LHTL is crucial for optimizing training protocols.
• Sleep quality and breathing patterns are vital indicators of physiological adaptation to altitude.

Purpose of the Study:

• To compare sleep disordered breathing between normobaric hypoxia (NH) and hypobaric hypoxia (HH) during LHTL altitude camps.
• To assess the impact of NH versus HH on breathing frequency, oxygen saturation, and oxygen desaturation index in trained athletes.
• To determine which hypoxia simulation method leads to more significant sleep disturbances in an LHTL context.

Main Methods:

• Sixteen elite triathletes participated in two 18-day LHTL camps using a crossover design.
• Athletes trained at 1100-1200m while sleeping under either simulated normobaric hypoxia (2250m) or hypobaric hypoxia.
• Continuous monitoring of breathing frequency and oxygen saturation (SpO2), with calculation of the oxygen desaturation index (ODI 3%).

Main Results:

• Breathing frequency was significantly lower in NH (14.6 breaths/min) compared to HH (17.2 breaths/min).
• Oxygen saturation (SpO2) was lower in HH (90.8%) than in NH (91.9%).
• The oxygen desaturation index (ODI 3%) was significantly higher in HH (15.1) than in NH (9.9), indicating more frequent desaturations.

Conclusions:

• Sleep in moderate hypobaric hypoxia is more disruptive than in normobaric hypoxia during a live high-train low camp.
• Hypobaric hypoxia appears to induce more significant sleep-disordered breathing events compared to normobaric hypoxia.
• These findings suggest that the type of hypoxia simulation used in LHTL training can differentially affect sleep quality and respiratory patterns.