Filipe Barata

Abstract Systemic inflammation (“inflammaging”) accelerates biological aging and drives cardiovascular, metabolic, and neurodegenerative disease. Circadian rhythms regulate the amplitude and timing of immune responses, yet their mechanistic role in inflammation and longevity remains unexplored.

1 Introduction The multiple sleep latency test (MSLT) was developed as a ‘measure of physiological sleep tendency in the absence of altering factors’ (Carskadon and Dement 1982). Briefly, the MSLT is an objective test that traditionally consists of four to five daytime naps administered 2-h apart, with the protocol occurring on the day following an in-laboratory nighttime polysomnography (PSG) (Krahn et al. 2021).

Abstract Recognizing the pivotal role of circadian rhythm in the human aging process and its scalability through wearables, we introduce CosinorAge, a digital biomarker of aging developed from wearable-derived circadian rhythmicity from 80,000 midlife and older adults in the UK and US. A one-year increase in CosinorAge corresponded to 8–12% higher all-cause and cause-specific mortality risks and 3–14% increased prospective incidences of age-related diseases.