Response of bone mineral density, inflammatory cytokines, and biochemical bone markers to a 32-week combined loading exercise programme in older men and women

Abstract

This study examines the effects of 32 weeks of exercise training on balance, lower-extremity muscle strength, bone mineral density (BMD) and serum levels of bone metabolism and inflammatory markers in older adults. Forty-seven healthy older adults (women=24, men=23; mean age 68.2 years) participated in a exercise intervention (60min/session) that included resistance exercise training (2 days/week) at 75–80% of maximum plus a multicomponent weight-bearing impact exercise training (1 day/week). Outcome measures included lumbar spine and proximal femoral BMD, dynamic balance, muscle strength, serum levels of bone metabolism markers [osteocalcin (OC), C-terminal telopeptide of Type I collagen (CTX), osteoprotegerin (OPG) and receptor activator of nuclear factor kappa B ligand (RANKL)] and serum levels of inflammatory markers [high sensitive (hs)-C-reactive protein (CRP), interleukin (IL)-6, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ]. Potential confounding variables included body composition, dietary intake (using 4-day diet records), and accelerometer-based physical activity. After 32 weeks, both men and women increased dynamic balance (6.4%), muscle strength (11.0%) and trochanter (0.7%), intertrochanter (0.7%), total hip (0.6%), and lumbar spine BMD (1.7%), while OC, CTX, OPG and RANKL levels remained unchanged. In addition, hs-CRP and IFN-γ levels were decreased, while TNF-α levels were unchanged, and a decrease in IL-6 levels was only observed in men. These findings suggest that our combined impact protocol reduces inflammation and increases BMD, balance, and lower-extremity muscle strength, despite having little effect on bone metabolism markers. This reinforces the role of exercise to counteract the age-related inflammation, and the muscle strength, balance and BMD reduction.