Altitude Differences in Changes in Physical Activity and Weight Gain.

Area of Science:

• Exercise physiology
• Environmental health
• Public health

Background:

• Speculation exists that physical activity (PA) at high altitude confers greater exercise benefits than at low altitude.
• Validation of this speculation is needed to inform public health guidelines.
• Understanding altitude's impact on PA and weight management is crucial.

Purpose of the Study:

• To investigate the relationship between changes in physical activity (PA) and changes in weight and body mass index (BMI) at low and high altitudes.
• To determine if altitude modifies the association between PA changes and weight/BMI changes.
• To provide evidence for altitude-specific PA recommendations.

Main Methods:

• Multivariable linear regression analysis was used to assess relationships between PA changes and weight/BMI changes.
• Participants were stratified into low altitude (<2500 m) and high altitude (≥2500 m) groups.
• Stratified analyses examined heterogeneity in the PA-weight relationship across altitudes.

Main Results:

• A total of 10,000 individuals (9122 low altitude, 878 high altitude) were included.
• Increases in PA were inversely associated with weight changes in both low (-0.009 kg) and high (-0.032 kg) altitudes.
• The inverse relationship between PA and weight change was significantly stronger at high altitude (P = .016).

Conclusions:

• Altitude significantly modifies the relationship between physical activity and weight change.
• Physical activity interventions and guidelines should consider altitude differences.
• PA recommendations may need to be lower for high-altitude populations compared to low-altitude populations.