Fatigue May Contribute to Reduced Physical Activity Among Older People: An Observational Study

Fatigue is one of the most commonly reported symptoms in primary care and perceived by older people as an overwhelming and distressing experience that restricts their activity and social participation. Self-reported fatigue is complex and multifactorial, with relatively little known about the causes and impacts among older people. This study tested the association between fatigue and objectively measured physical activity in a large cohort of older adults and identified factors that may explain this association.

Using cross-sectional data from 980 community-living 70- to 77-year-olds, the associations between self-reported fatigue and four physical activity outcomes derived from an accelerometer-based activity monitor were tested. Attenuating effects on the association of age, gender, body mass index (BMI), physical condition, comorbidity, depression, and sleep quality were evaluated.

Nine percent of the sample reported being fatigued. Fatigued individuals had 1,150 fewer steps/day, 9 minutes/day less of moderate-vigorous activity, 12 minutes/day less of daily activity, and 15% fewer counts/minute, when compared with those not fatigued. BMI, physical condition, and comorbidity attenuated the association, and final regression models including these variables explained most (56%-72%) of the association between fatigue and activity.

Fatigue was associated with clinically important reductions in daily physical activity levels of older people. The findings show BMI, physical condition (in particular cardiorespiratory fitness), and comorbidity to be important factors in explaining the fatigue-physical activity association. Modification of these factors may facilitate increases in daily activity levels by lessening fatigue.