How Chronotype Changes with Age

How Chronotype Changes with Age

Chronotype is the behavioural expression of an individual's endogenous circadian timing system, commonly classified as morning, intermediate or evening type. It is also referred to as diurnal preference or circadian typology. Chronotype is not a fixed trait: it changes across the lifespan, typically showing a shift toward eveningness during adolescence and a subsequent advance toward morningness with increasing age. The evidence base for these age-related changes comes from observational cohort studies, clinical trials and narrative reviews, and the mechanisms involve the circadian clock, sleep–wake regulation and associated metabolic pathways.

The work in this area centres on the circadian rhythm system and its interaction with sleep, metabolism and behaviour, including the hypothalamic suprachiasmatic nucleus and peripheral clock genes, as well as the melatonin and cortisol axes.

Research Studies

Chronotype and exercise timing in prediabetes

A clinical trial is investigating whether exercising at the right time of day, based on a person's natural body clock, leads to greater health benefits in people living with prediabetes [1]. The main question is whether a single session of exercise in the morning or in the evening affects how the body handles sugar differently in adults with prediabetes who have an extreme natural body clock. The study compares three conditions — no exercise, morning exercise and evening exercise — within the same participant, with each condition tested on a different day and at least 14 days between test days [1]. This work is in adults with prediabetes and an extreme chronotype; it does not directly test age-related chronotype change, but it addresses how chronotype interacts with metabolic responses to exercise.

Chronotype and insomnia in adolescents with ADHD

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterised by persistent inattention, hyperactivity and impulsivity. In adolescents and young people, ADHD is commonly accompanied by insomnia and circadian delay [2]. These co-occurring sleep and circadian disturbances may negatively affect daytime functioning and overall clinical outcomes. Although cognitive behavioural therapy for insomnia (CBT-I) is considered the first-line treatment for insomnia, and bright light therapy may help address circadian issues, their efficacy in adolescents with ADHD and comorbid insomnia and eveningness remains unexplored [2]. This study aims to evaluate whether CBT-I, with or without bright light therapy, improves outcomes in this population. The findings will be specific to adolescents with ADHD, insomnia and an evening chronotype.

Exercise timing and performance in athletes and active adults

A structured narrative review synthesised evidence on morning versus afternoon/evening training in athletes and physically active adults, integrating performance outcomes with internal load, autonomic recovery, sleep interaction and downstream physiological stress [3]. Acute evidence generally supports superior late-afternoon or early-evening performance, particularly for neuromuscular tasks, whereas chronic training studies do not indicate a universal optimal training time [3]. The review notes that time of day is often treated as a scheduling constraint rather than a true programming variable, yet training time is not neutral and can modulate both performance expression and the biological cost of exercise [3]. This evidence is in athletes and physically active adults and does not directly address age-related chronotype change, but it shows that chronotype and time of day influence physiological responses.

Chronotype, nocturia and pelvic floor symptoms in women with urinary incontinence

Urinary incontinence (UI) is the involuntary leakage of urine that negatively affects individuals socially, physically and psychologically, leading to a decreased quality of life. Nocturia, often seen alongside UI, has similar adverse effects. Nocturia refers to the number of urinations during the main sleep period and should be accompanied by the intention to fall back asleep after waking up [4]. Nocturia can arise from factors such as sleep disorders and circadian rhythm disturbances. The circadian rhythm regulates the body's biological functions, and this rhythm varies from person to person, creating chronotypes [4]. There is a strong relationship between sleep and chronotype in this context. This study examines the effect of nocturia on pelvic floor symptoms, sleep parameters and quality of life in women with urinary incontinence [4]. The findings are specific to women with UI and nocturia and do not directly test age-related chronotype change.

Sleep health, metabolic signatures and stroke risk

A prospective cohort study included 200,729 UK Biobank participants and investigated whether a nuclear magnetic resonance-derived metabolic signature mediates the association between healthy sleep and lower stroke risk [5]. The study found that healthy sleep was associated with lower stroke risk, and metabolic mechanisms may partly explain this association [5]. This evidence is from a large observational cohort and is reference-only for the present page; it supports the broader link between sleep health, metabolism and disease risk but does not directly address chronotype change with age.

Summary of age-related chronotype patterns

Across the evidence, chronotype is treated as a variable that changes with age and interacts with health outcomes. The table below summarises the populations and key observations from the cited studies.

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Sources

• [1] Exercise, Chronotype, and Prediabetes
• [2] Efficacy of Cognitive Behavioural Therapy for Insomnia and Bright Light Therapy in Adolescents With ADHD, Insomnia, and Evening Chronotype
• [3] Exercise Timing in Sport: Molecular and Physiological Mechanisms Linking Performance, Recovery, and Biological Cost.
• [4] Examination of the Effect of Nocturia on Pelvic Floor Symptoms, Sleep Parameters and Quality of Life in Women With Urinary Incontinence
• [5] Metabolic signatures of sleep health and stroke risk: A prospective cohort study with mediation analysis.