Variability in hemoglobin mass response to altitude training camps

Area of Science:

• Sports Science
• Exercise Physiology
• Altitude Training

Background:

• Altitude training is a common strategy for endurance athletes to enhance performance.
• Individual responses to altitude exposure, particularly changes in total hemoglobin mass (tHb-mass), can vary significantly.
• Understanding factors influencing these responses is crucial for optimizing training protocols.

Purpose of the Study:

• To determine if athletes can be classified as responders or non-responders to altitude training based on tHb-mass changes.
• To identify factors affecting individual responsiveness to altitude exposure.
• To analyze the variability in tHb-mass response within and between athletes.

Main Methods:

• Measured tHb-mass using the CO rebreathing method before and after 82 altitude training camps (1350-2500m) in 59 elite endurance athletes.
• Collected data from athletes who underwent multiple altitude training camps.
• Utilized logistic regression analysis to identify significant factors influencing tHb-mass response.

Main Results:

• Total hemoglobin mass increased in 56% of altitude training camps, rising to 65% for camps above 2000m.
• Among athletes with multiple camps, 27% consistently showed positive tHb-mass response, 13% negative, and 60% mixed responses.
• Higher altitude was the most significant factor for positive tHb-mass response, and male athletes exhibited greater response than females.

Conclusions:

• Altitude training can increase tHb-mass in endurance athletes if the hypoxic stimulus is adequate.
• Significant inter- and intra-individual variability in tHb-mass response exists, precluding permanent responder/non-responder classification.
• Controlling factors influencing individual responses is essential for each altitude training camp.