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The Food and Drug Administration's (FDA) obesity drug guidance is set on the basis of body mass index (BMI), with thresholds of either BMI ≥30 or BMI ≥27 kg/m² with weight-related comorbidities. While BMI is associated with obesityrelated health outcomes, there are known limitations to use as a direct measure of body fat or metabolic health, and the American Medical Association has highlighted limitations of BMI in assessing individual obesity risks. BMI thresholds impose a barrier to treatment. In a sample from the NHANES dataset (n=6,646 men and women), 36% of individuals with metabolic syndrome (MetS) may not be eligible for obesity pharmacotherapy. This analysis provides quantifiable justification for refinement of the BMI treatment criteria with a more holistic assessment of individual obesity-related disease risk. [ABSTRACT FROM AUTHOR]

Few US Marines earn perfect 300 scores on both their Physical Fitness Test (PFT) and Combat Fitness Test (CFT). The number 300 invokes the legendary 300 Spartans that fought at the Battle of Thermopylae, which inspired high physical fitness capabilities for elite ground forces ever since. Purpose: Determine distinguishing characteristics of the "300 Marines" (perfect PFT and CFT scores) that may provide insights into the physical and physiological requirements associated with this capability. These tests have been refined over time to reflect physical capabilities associated with Marine Corps basic rifleman performance. Materials and methods: Data were analyzed from US Marines, including 497 women (age, 29 ± 7 years; height 1.63 ± 0.07 m; body mass, 67.4 ± 8.4 kg) and 1,224 men (30 ± 8 years; 1.77 ± 0.07 m; 86.1 ± 11.1 kg). Marines were grouped by whether they earned perfect 300 scores on both the PFT and CFT (300 Marines) or not. We analyzed group differences in individual fitness test events and body composition (dual-energy x-ray absorptiometry). Results: Only 2.5% (n = 43) of this sample earned perfect PFT and CFT scores (n = 21 women; n = 22 men). Compared to sex-matched peers, 300 Marines performed more pull-ups, with faster three-mile run, maneuver-under-fire, and movement-to-contact times (each p < 0.001); 300 Marines of both sexes had lower fat mass, body mass index, and percent body fat (each p < 0.001). The lower percent body fat was explained by greater lean mass (p = 0.041) but similar body mass (p = 0.085) in women, whereas men had similar lean mass (p = 0.618), but lower total body mass (p = 0.025). Conclusion: Marines earning perfect PFT and CFT scores are most distinguished from their peers by their maneuverability, suggesting speed and agility capabilities. While both sexes had considerably lower percent body fat than their peers, 300 Marine women were relatively more muscular while men were lighter. [ABSTRACT FROM AUTHOR]

Objective: Determine if relative body fat (%BF) remains a biological norm in physically active, non‐obese American men and women and determine reference values for other components of body composition. Methods: Participants (n = 174 men, 70 women) were physically fit U.S. Marine 2nd Lieutenants, in their third decade of physical maturity (age 21–30). Body composition was assessed by dual‐energy x‐ray absorptiometry (DXA) and bioelectrical impedance analysis (BIA); and body images were obtained by 3D body scans. Results: For men and women, respectively, %BF averaged 16.2 ± 4.1 (median 15.3), 24.3 ± 4.5 (median 23.8); fat‐free mass (FFM): 67.7 ± 7.2, 49.4 ± 5.3 kg; FFM index: 21.5 ± 1.8, 18.3 ± 1.6 kg/m2; and body mass index (BMI): 25.5 ± 1.9, 24.1 ± 2.2 kg/m2. Bone mineral content (BMC) was 5% of FFM; total body water (TBW) was 70%–72% of FFM. Physique remained similar between median and higher percentiles of %BF. Only small changes in key measures were noted across the six‐month training program. Conclusions: Mean %BF of healthy active men and women in 2021 remains very similar to the 15% and 25% posited in 1980, suggesting that relative body fat has a normal fat‐lean relationship in physically mature humans. These data may bring new attention to sex‐appropriate %BF. [ABSTRACT FROM AUTHOR]

Biomathematical models quantitatively describe human physiological responses to environmental and operational stressors and have been used for planning and real-time prevention of cold injury. These same models can be applied from a military tactical perspective to gain valuable insights into the health status of opponent soldiers. This paper describes a use case for predicting physiological status of Russian soldiers invading Ukraine using open-source information. In March 2022, media outlets reported Russian soldiers in a stalled convoy invading Ukraine were at serious risk of hypothermia and predicted these soldiers would be "freezing to death" within days because of declining temperatures (down to −20°C). Using existing Army models, clothing data and open-source intelligence, modelling and analyses were conducted within hours to quantitatively assess the conditions and provide science-based predictions. These predictions projected a significant increase in risks of frostbite for exposed skin and toes and feet, with a very low (negligible) risk of hypothermia. Several days later, media outlets confirmed these predictions, reporting a steep rise in evacuations for foot frostbite injuries in these Russian forces. This demonstrated what can be done today with the existing mathematical physiology and how models traditionally focused on health risk can be used for tactical intelligence. [ABSTRACT FROM AUTHOR]