Inter‐individual variation in responses to resistance training in cardiometabolic health indicators

Abstract Resistance training (RT) may improve metabolic health; however, the extent of its effectiveness is constantly evaluated to assess improvements in the group means, thus obscuring the heterogeneous individual effects. This study investigated inter‐individual variation in responses to RT as reflected in metabolic health indicators and how age, sex, nutrition and pre‐training phenotypes are associated with such variabilities. Methods Previously collected data of men and women (39‐73 years, 135 trained, 73 non‐trained controls) were pooled for analysis. Measurements were taken twice before training to estimate individual day‐to‐day variations and measurement errors (n=208). The individual responsiveness to the 21‐week RT in cardiometabolic health indicators (i.e., systolic blood pressure, high‐density lipoprotein cholesterol (HDL‐C), cholesterol and triglycerides) was determined. Body composition was estimated by bioimpedance and dietary intake according to four‐day food diaries. Results Metabolic responses to RT seemed to be highly individual, and both beneficial and unfavourable changes were observed. Large inter‐individual variations in training response were not explained by a subject’s age, sex, body composition or nutritional status, with the exception of improvements in HDL‐C, which were associated with simultaneous decreases in body fat in older women. The incidence of metabolic syndrome diminished following RT. Conclusion This study showed that RT could improve some specific metabolic health indicators beyond normal day‐to‐day variations, especially in blood lipid profile. Further studies are needed to elucidate genetic and other mechanisms underlining the heterogeneity of RT responses. This knowledge may be useful in providing individually tailored exercise prescriptions as part of personalised preventative health care.