Dale R Wagner, Edward M Heath, Macy Gustavus
A 24-year-old premenopausal female adult completed the entire Pacific Crest Trail, an arduous backpacking thru-hike of 4265 km. Dual-energy x-ray absorptiometry measurements were taken before and after the trek. Her body fat percentage dropped from 33.2% to 24.9%, and there was a 52% decrease in visceral adipose tissue mass and area. Total body bone mineral content and bone mineral density (BMD) were retained; however, lumbar BMD decreased 3.8%. The hiker eventually regained this loss of lumbar BMD. A decrease in lumbar BMD despite engaging in load-bearing activity was also observed in two recent case study reports of male thru-hikers, suggesting a maladaptive response that warrants further investigation.