Metrics details. Fatigue, low muscle endurance, muscle weakness and low-grade inflammation are strongly related to frailty at higher age. When signs of self-perceived fatigue and low muscle endurance are interrelated with low-grade inflammation at midlife, they might be used as early markers for frailty.
This study investigated whether the interrelationships among self-perceived fatigue, muscle endurance and inflammation can be observed at midlife. Overall, muscle endurance, fatigue and inflammatory markers were significantly interrelated. Middle-aged participants with higher fatigue in combination with low muscle endurance show higher levels of inflammation, independently from physical activity, body fat and inflammatory pathology.
The underlying mechanisms should be identified and future studies should also investigate whether these individuals show early signs of reduced physiological reserve capacity, which in later life come to full expression by means of frailty.
Fatigue is a common reported complaint among older adults and is increasingly acknowledged as a geriatric syndrome [ 1 ]. It poses a significant risk for adverse health outcomes, such as disability, falls, hospitalization and mortality in older adults [ 2 ]. Research has shown that muscle strength declines with age and contributes significantly i. Sufficiently high maximal strength is crucial for the ability to perform functional tasks including rising from a chair or lifting objects.
However, in older persons, continuing and completing these tasks necessitates sustained muscle contractions at a nearly maximal intensity. Reduced muscle endurance might therefore explain the occurrence of fatigue, one of the key characteristics of physical frailty [ 4 , 5 ]. In the pathophysiology of frailty and fatigue, inflammation has been recognized to play a predominant role in older adults [ 7 ], however none of the studies has showed this relationship already at midlife.
