Hypoxic re-exposure retains hematological but not performance adaptations post-altitude training

Area of Science:

• Sports Science
• Exercise Physiology
• Altitude Training

Background:

• Natural altitude training enhances hematological and performance adaptations.
• The retention of these adaptations after returning to sea level is crucial for athletes.
• Hypoxic re-exposure strategies are being explored to prolong training benefits.

Purpose of the Study:

• To investigate if hypoxic re-exposure post-altitude training aids in retaining hematological and performance adaptations.
• To compare the effects of living high-training low (LHTL) versus living low-training low (LLTL) on adaptation retention.

Main Methods:

• Eighteen mixed martial art fighters underwent a 3-week altitude training camp (2418m).
• Participants were then randomized into LHTL (simulated 2800m for 12h/d) or LLTL groups for 3 weeks of sea-level training.
• Hematological (hemoglobin mass) and performance (3000m time trial, VO2max) markers were assessed at baseline and during the sea-level period.

Main Results:

• Hemoglobin mass increased significantly post-altitude and remained elevated in the LHTL group, while returning to baseline in the LLTL group.
• Maximal oxygen uptake (VO2max) showed transient increases at specific time points but no sustained group difference.
• 3000m time trial performance improved at days 4 and 15 compared to baseline, irrespective of the group.

Conclusions:

• Hypoxic re-exposure can help maintain hemoglobin mass gains after altitude sojourns.
• However, this strategy does not confer a performance advantage at sea level.
• Results support observations of alternating optimal and attenuated performance upon return from altitude.