A 2-year follow-up to a randomized controlled trial on resistance training in postmenopausal women: vasomotor symptoms, quality of life and cardiovascular risk markers

Background Most women experience vasomotor symptoms (VMS) during the menopausal transition. A 15-week resistance training intervention (RTI) significantly reduced moderate-to-severe VMS (MS-VMS) and improved health-related quality of life (HRQoL) and cardiovascular risk markers in postmenopausal women. Whether a short RTI could have long-term effects is unknown. We aimed to investigate whether there were intervention-dependent effects two years after a 15-week RTI on MS-VMS frequency, HRQoL, and cardiovascular risk markers in postmenopausal women. Methods This observational prospective cohort study is a follow-up to a randomized controlled trial (RCT) on a 15-week RTI in postmenopausal women (n = 57). The control group had unchanged low physical activity during these first 15 weeks. At the follow-up contact two years post-intervention, 35 women agreed to participate in an additional physical visit at the clinic with clinical testing, blood sampling, and magnetic resonance imaging, identical to the protocol at the baseline visit at the start of the RCT. Results Although all women showed reduced MS-VMS and increased moderate-to-vigorous physical activity (MVPA) over the 2-year follow-up compared to baseline, the groups from the original RCT (intervention group; IG, control group; CG) changed differently over time (p < 0.001 and p = 0.006, respectively) regarding MS-VMS. The IG maintained a significantly lower MS-VMS frequency than the CG at the 6-month follow-up. At the 2-year follow-up, there was no significant difference between the original RCT groups. No significant changes over time or differences between groups were found in HRQoL or cardiovascular risk markers. However, significant interactions between original RCT groups and time were found for visceral adipose tissue (p = 0.041), ferritin (p = 0.045), and testosterone (p = 0.010). Conclusions A 15-week resistance training intervention reduced MS-VMS frequency up to six months post-intervention compared to a CG, but the effect was not maintained after two years. The RTI did neither contribute to preserved improvements of cardiovascular risk markers nor improved HRQoL after two years compared to a CG. Trial registration Clinical trials.gov registered ID: NCT01987778, trial registration date 2013-11-19.