Redox rhythms promote fitness by modulating ageing-dependent reprogramming.

Ageing leads to diurnal misalignment with a global reduction in physiological fitness, yet the mechanisms underlying such age-related diurnal reprogramming and its role in ageing remain poorly understood. Here we generate diurnal transcriptomes across eight peripheral tissues and reveal that disrupted redox oscillations are common diurnal alterations in organismal ageing. Restoring redox rhythms through the time-restricted application of antioxidants and pro-oxidants markedly improved glucose metabolism, motor performance and ageing-related characteristics of liver and skeletal muscle in male aged mice. Through multi-omics analyses we further reveal that restoring redox rhythms partially rejuvenates the hepatic transcriptome and chromatin accessibility in ageing-associated functional pathways and involves redox modification of CLOCK protein. Perturbing redox-sensitive cysteine 195 of CLOCK causes premature ageing phenotypes and hepatic reprogramming. Overall, our study reveals that redox rhythms ameliorate functional decline by modulating ageing-relevant reprogramming in liver and skeletal muscle and indicates that redox rhythm-based interventions might promote healthy ageing.