Association Between Adiposity and Perceived Physical Fatigability in Mid- to Late Life

Objective: This study aimed to compare and contrast the associations between measures of adiposity and fat distribution and perceived fatigability among well-functioning individuals in mid- to late life. Methods: In 1,054 adults (70.4 ± 12.4 years, 52% female), adiposity was measured as BMI, percent fat (dual-energy x-ray absorptiometry), waist and hip circumferences, and waist to height ratio. In a subset of 383 participants, visceral fat was measured. Perceived fatigability was evaluated after a 5-minute treadmill walk (1.5 mph) using the Borg rating of perceived exertion (range, 6-20). Associations between adiposity measures and perceived fatigability were assessed using regression models adjusting for age, sex, race, smoking, and comorbidities. Results: All adiposity measures, except subcutaneous fat, were positively associated with perceived fatigability after adjustment (P < 0.05 for all). Standardized coefficients indicated that BMI, hip circumference, and visceral fat had the strongest associations with fatigability. Associations between BMI and fatigability were present only among those above the threshold for overweight and strongest in those aged ≥ 65 years. Moreover, BMI was associated with fatigability only among participants with higher waist circumference. Conclusions: Measures of adiposity, particularly central adiposity, are strongly associated with fatigability, suggesting that weight management may be an effective target for curbing fatigability and maintaining quality of life with aging.