Smoking Impact on Grip Strength and Fatigue Resistance: Implications for Exercise and Hand Therapy Practice

Abstract

Background:Grip strength assessment reflects on overall health of the musculoskeletal system and is a predictor of functional prognosis and mortality. The purpose of this study was: examine whether grip-strength and fatigue resistance are impaired in smokers, determine if smoking-related impairments (fatigue-index) can be predicted by demographic data, duration of smoking, packets smoked-per-day, and physical activity.Methods:Maximum isometric grip strength (MIGS) of male smokers (n = 111) and nonsmokers (n = 66) was measured before/after induced fatigue using Jamar dynamometer at 5-handle positions. Fatigueindex was calculated based on percentage change in MIGS initially and after induced fatigue.Results:Number of repetitions to squeeze the soft rubber ball to induce fatigue was significantly lower in smokers compared with nonsmokers (t = 10.6, P < .001 dominant hand; t = 13.9, P < .001 nondominant), demonstrating a significantly higher fatigue-index for smokers than nonsmokers (t = –8.7, P < .001 dominant hand; t = –6.0, P < .001 nondominant). The effect of smoking status on MIGS scores was significantly different between smokers and nonsmokers after induced fatigue (β = –3.98, standard error = 0.59, P < .001) where smokers experienced on average a reduction of nearly 4 MIGS less than nonsmokers before fatigue. Smoking status was the strongest significant independent predictor of the fatigue-index.Conclusions:Smokers demonstrated reduced grip strength and fast fatigability in comparison with nonsmokers.