L-carnosine

Biological ageing involves a gradual decline in physiological function and resilience, marked by molecular, cellular, and systemic changes across organ systems. Geroscience, an interdisciplinary field, studies these mechanisms and their role in age-related diseases. Genomic instability, inflammation, telomere attrition, and other indicators contribute to conditions like cardiovascular disease and neurodegeneration. Geroscience identifies geroprotectors, such as resveratrol and metformin, targeting ageing pathways to extend the healthspan. Carnosine, a naturally occurring dipeptide (b-alanine and l-histidine), has emerged as a potential geroprotector with antioxidative, anti-inflammatory, and anti-glycating properties. Carnosine's benefits extend to muscle function, exercise performance, and cognitive health, making it a promising therapeutic intervention for healthy ageing and oxidative stress-related pathologies. In this review, we summarize the evidence describing carnosine's effects in promoting healthy ageing, providing new insights into improving geroscience.

Running economy is an important determinant of endurance running performance, yet insights into characteristics contributing to its inter‐individual variability remain limited. Although slow‐twitch muscle fibers are more energy‐efficient than fast‐twitch fibers during the (near‐)isometric contractions common during submaximal running, current literature lacks a consensus on whether a relationship between muscle fiber–type distribution and running economy exists. This study aims to resolve the ongoing debate by addressing potential confounding factors often overlooked in prior research, such as the effect of different running speeds, the homogeneity of investigated groups, and the potential impact of the adopted running gait. We selected two groups with predetermined distinct muscle fiber–type distribution in their triceps surae muscle by measurement of carnosine via 1H‐MRS, one predominantly slow (ST; n = 11; carnosine z‐score = −1.31) and the other predominantly fast (FT; n = 10; z‐score = 0.83). Across a range of running speeds (2–4 m/s), we measured running economy (W/kg) through indirect calorimetry, along with running kinematics, kinetics and muscle activity of the lower limb. The ST‐group exhibited, on average, 7.8% better running economy than the FT‐group (p = 0.01) and this difference was consistent across speeds. Both groups demonstrated almost identical kinematics, kinetics, and muscle activity patterns across submaximal running speeds. Overall, our findings indicate that distinct muscle fiber–type distribution explains some of the observed variability in running economy, for which a predominance of energy‐efficient slow‐twitch fibers appear beneficial. In contrast, muscle fiber–type distribution does not affect running gait substantially.