Handgrip Strength-Related Factors Affecting Health Outcomes in Young Adults: Association with Cardiorespiratory Fitness

Objectives: Handgrip strength (HS) is a risk factor of all-cause mortality and cardiovascular diseases. However, the influencing factors and mechanisms contributing to this correlation remain unclear. Therefore, we aimed to explore factors related to HS and investigated the mechanism underlying its risk predictive value.

Methods: This was a prospective, cross-sectional study. One hundred forty-five participants were recruited from December 2019 to November 2020. HS was measured using a hydraulic hand dynamometer and adjusted for body mass index (HS_BMI) and body surface area (HS_BSA). Body composition was assessed via bioimpedance spectroscopy. Physical fitness was measured using a cardiopulmonary exercise test system. Univariate, multiple linear regression analyses and receiver operator characteristic curve (ROC) were conducted to evaluate the associations between various participant characteristics and HS.

Results: The average participant age was 21.68 ± 2.61 years (42.8% were male). We found positive correlations between HS_BMI/HS_BSA and VO_2max, VE_max, Load_max, and MET_max in both sexes (p < 0.05). Lean-tissue, protein, total water, and inorganic salt percentages were positively correlated, and fat percentage was negatively correlated with HS_BMI in men and with HS_BMI and HS_BSA in women (p < 0.05). Multiple regression revealed that VO_2max was independently associated with HS_BSA in both sexes (β = 0.215, 0.173; 95%confidence interval [CI] = 0.032 - 0.398, 0.026-0.321; p = 0.022, 0.022, respectively) and independently associated with HS_BMI in women (β = 0.016, 95%CI = 0.004 - 0.029, p = 0.011). ROC analysis showed that HS_BMI and HS_BSA can moderately identify normal VO_2max in men (area under curve [AUC] = 0.754, 0.769; p = 0.002, 0.001, respectively) and marginally identify normal VO_2max in women (AUC = 0.643, 0.635; p = 0.029, 0.042, respectively).

Conclusions: BMI- and BSA-adjusted HS could serve as indicators of physical health, and HS_BSA may moderately reflect cardiorespiratory fitness levels in healthy young adults, particularly in males. Clinical trials registry site and number: China Clinical Trial Center (ChiCTR1900028228).