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Exercise & fitness

DEXA scan (body composition)

DEDEXA-Scan (Körperzusammensetzung)

A DEXA scan (dual-energy X-ray absorptiometry) measures your body composition and bone density. It passes two X-ray beams at different energy levels through your body and measures how each is absorbed. From that, it splits you into lean mass, fat mass, and bone mineral, both region-by-region and whole-body, with high precision and low radiation (about 1-5 µSv on modern scanners, up to ~10 on older ones). One DEXA-derived number, the appendicular lean mass index (ALMI = arm + leg lean mass in kg, divided by height in m²), is used in the EWGSOP2 criteria for sarcopenia. Modern scanners increasingly estimate visceral fat (VAT) too. Repeat DEXA scans track how your muscle and fat change with training, diet, and aging interventions. The main limitations: lean-mass readings are sensitive to your hydration, and results vary by scanner model.

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Sources

  1. Kelly TL, Wilson KE, Heymsfield SB. (2009). Dual energy X-ray absorptiometry body composition reference values from NHANES. *PLOS ONE*doi:10.1371/journal.pone.0007038
  2. Kanis JA. (1994). Assessment of fracture risk and its application to screening for postmenopausal osteoporosis: synopsis of a WHO report. *Osteoporosis International*doi:10.1007/BF01622200

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