STIM1 and sarcopenia: Morphological investigations of Stim1+/− muscle sections by light and electron microscopy uncovered a shift towards slow myofibres and mitochondrial proliferation accompanied by enhanced SDH activity (Δ = 27%, p < 0.0001), an almost twofold increase in ROS production (p < 0.05), and signs of mitophagy—all representing histopathological hallmarks of age‐related deterioration of muscle function known as sarcopenia.