Muscle endurance in elderly nursing home residents is related to fatigue perception, mobility, and circulating tumor necrosis factor-alpha, interleukin-6, and heat shock protein 70

OBJECTIVES: To explore the relationships between muscle endurance and circulating interleukin (IL)-6, tumor necrosis factor alpha (TNF-alpha), and heat shock protein (Hsp)70 in nursing home residents and to assess how muscle endurance relates to self-perceived fatigue and mobility. DESIGN: Exploratory study. SETTING: Three nursing homes of the Foundation for Psychogeriatrics (Brussels, Belgium). PARTICIPANTS: Seventy-seven residents (53 female and 24 male, mean age 81 +/- 8). MEASUREMENTS: Participants were assessed for muscle endurance (fatigue resistance and grip work); perceived fatigue (visual analogue scale for fatigue); fatigue during daily activities (Mobility-Tiredness Scale); effect of fatigue on quality of life (World Health Organization Quality Of Life questionnaire); mobility (Tinetti Test & Elderly Mobility Scale (EMS)); and circulating IL-6, TNF-alpha, and Hsp70. RESULTS: Residents with better fatigue resistance reported less self-perceived tiredness (P <.05). Similar trends were observed for fatigue during daily activities and for the extent to which fatigue bothered subjects. Higher grip work was associated with less self-perceived fatigue on all fatigue scales (P <.01). Fatigue resistance and grip work were positively related to balance and basic mobility (all P <.01; trend for relationship between fatigue resistance and EMS). Subjects with high IL-6 and Hsp70 showed significantly worse fatigue resistance (P=.007) and muscle work (P=.045) than those with high IL-6 and low Hsp70. In male residents, higher TNF-alpha was related to worse fatigue resistance and grip work (P <.05). CONCLUSION: Elderly nursing home residents complaining of fatigue need to be taken seriously, because they show worse muscle endurance, which is related to poorer mobility. Inflammatory processes involving TNF-alpha and the interaction between IL-6 and Hsp70 are related to poorer muscle endurance in these patients.