Purpose: Long-term exercise improves bone health eliciting anabolic effects if characterised by progressive, dynamic, novel patterns and applied rapidly. Acute-exercise effects with varying mechanical stimuli is less clear. Bone turnover markers (BTMs), surrogate measures of bone health, are used to measure acute exercise-responses, but findings are contradictory possibly owing to factors (feeding, circadian-effects) modulating responses. This systematic review examines the effects of acute aerobic (AE), resistance (RE) and impact exercises on BTMs in middle and older-aged adults.
Methods: We searched PubMed, SCOPUS, Web of Science and EMBASE up to 22nd April 2020. Eligibility criteria: randomised controlled trials (RCTs) and single-arm studies; middle-aged (50 to 65 years) and older adults (>65 years); a single-bout, acute-exercise (AE, RE, impact) intervention with measurement of BTMs. PROSPERO registration number CRD42020145359
Results: Thirteen studies were included; 8 in middle-aged (n= 275, 212 women/63 men, mean age= 57.9 ± 1.5 years) and 5 in older-adults (n= 93, 50 women/43 men, mean age= 68.2 ± 2.2 years). Eleven studies included AE (7 middle-aged/4 older-adults), and two included RE (both middle-aged). AE significantly increased C-terminal telopeptide (CTX), alkaline phosphatase (ALP) and bone-ALP in middle-aged and older-adults. AE also significantly increased total osteocalcin (tOC) in middle-aged men and Procollagen I Carboxyterminal Propeptide and Cross‐Linked Carboxyterminal Telopeptide of Type I Collagen in older women. RE alone decreased ALP in older-adults. In middle-aged adults, RE with impact had no effect on tOC or BALP, but significantly decreased CTX. Impact (jumping) exercise alone increased Procollagen Type 1 N Propeptide and tOC in middle-aged women. Quality assessment results identifies a lack of RCTs, low quality evidence, small sample sizes and large variance in protocols.
Conclusions: Acute exercise is an effective tool to modify BTMs, however, responses appear to be exercise modality-, intensity-, age- and sex-specific. Higher quality and larger RCTs are needed.