Partitioned weight loss and body composition changes during a mountaineering expedition: a field study

Area of Science:

• Sports Medicine
• Human Physiology
• Altitude Physiology

Background:

• Weight loss and body composition changes are common during high-altitude mountaineering.
• Previous studies have yielded inconclusive results regarding the partitioning of weight loss between fat mass and fat-free mass.

Purpose of the Study:

• To investigate body composition changes during a high-altitude expedition.
• To determine the primary drivers of weight loss and body composition alterations in mountaineers.

Main Methods:

• Studied five male subjects before, during, and after a 21-day expedition (2200m-4300m).
• Assessed body composition using densitometry, skinfold thickness, body girth measurements, and magnetic resonance imaging (MRI).
• Analyzed energy intake and its correlation with weight and body composition changes.

Main Results:

• Subjects experienced significant decreases in body weight (4.2 kg), skinfold thickness (10.8%), body girth (2.8%), and fat percentage (15%).
• MRI revealed decreases in total cross-sectional area (4.7%), muscle area (9.1%), and fat area (3.9%).
• Discrepancies were observed in fat mass vs. fat-free mass loss partitioning across different measurement methods (densitometry, skinfolds, MRI).

Conclusions:

• Insufficient energy intake was identified as the primary factor responsible for weight loss and body composition changes.
• The study highlights the complex interplay between energy balance and physiological adaptations at high altitudes.
• Accurate assessment of body composition changes requires consideration of multiple measurement techniques due to method-specific variations.