Early Time-Restricted Eating for Cardiovascular Health

Official title

Aligning Clocks: Time-Restricted Eating to Improve Cardiovascular Health in Hypertensive Older Adults Who Skip Breakfast

Overview

This study will examine whether eating earlier in the day within a consistent 8-hour eating window can improve heart and blood vessel health in older adults with high blood pressure who often skip breakfast. Participants will be randomly assigned to either follow an early time-restricted eating schedule or continue their usual eating habits for 12 weeks. Researchers will measure blood pressure, blood vessel function, and biological markers related to the body's internal clock and oxidative stress to better understand how meal timing affects cardiovascular health.

Detailed description

Aging is a major risk factor for cardiovascular disease, largely due to elevated blood pressure (BP) and endothelial dysfunction. These conditions are common in older adults and often coexist, and breakfast skipping has emerged as an additional contributor. Delaying the first meal creates misalignment between central and peripheral circadian rhythms that regulate vascular and metabolic processes. This misalignment alters cortisol patterns and impairs glucose and insulin responses, increasing inflammation and oxidative stress. These disturbances weaken endothelial function and disrupt vascular tone and diurnal BP rhythms, contributing to hypertension and underscoring the need for interventions that restore vascular health in older adults who skip or delay breakfast.

Early time-restricted eating (eTRE) is a promising strategy that aligns food intake with hormonal rhythms by shifting meals earlier in the day. eTRE may strengthen circadian rhythms, reduce oxidative stress, and improve cardiovascular function, yet its effects in older adults with hypertension remain understudied. This project will address this gap by implementing a 12-week eTRE to evaluate effects on vascular health and circadian rhythms and to explore participants' experiences with adopting eTRE.

Thirty-six adults aged 60 and older with breakfast-skipping behavior and hypertension (average daytime systolic BP ≥130 mmHg per AHA criteria) will be randomized to eTRE or control, with equal numbers of morning and evening chronotypes based on the Morningness-Eveningness Questionnaire. Cardiovascular outcomes will be assessed with 24-hour ambulatory BP monitoring and flow-mediated dilation. Fasting blood samples will be collected to measure circadian clock gene expression and redox biomarkers. To understand behavioral and perceptual factors, ten eTRE participants will join two focus groups (n=5 per group) to discuss changes in energy, sleep timing, and daily routines.

The central hypothesis is that eTRE will improve BP regulation and endothelial function, regardless of chronotype, by enhancing circadian alignment, restoring redox balance, and promoting greater daily structure. Findings from this pilot study will provide preliminary evidence for a future trial and guide strategies to improve cardiovascular health in older adults.

Interventions

• Behavioral Early Time-Restricted Eating (eTRE)
  Participants in the eTRE group will be asked to fast for a target of 16 hours per day (eat ad libitum within the 8-hour eating window, starting between 6:30-9:30 am), 6 days/week for 12 weeks. Participants will be allowed to consume calorie-free beverages, sugar-free gum, and will be encouraged to drink plenty of water throughout the entire intervention period.

Primary outcome measures

• 24-Hour Systolic Blood Pressure [Time frame: Baseline (Week 0), Week 6, and Week 12 of the intervention]

Secondary outcome measures (1)

• Flow-Mediated Dilation [Time frame: Baseline (Week 0), Week 6, and Week 12 of the intervention]

Eligibility criteria

Inclusion criteria

• Men and women ≥ 60 years old
• Average office systolic BP ≥130 mmHg5
• Self-reported skipping breakfast for at least 3 days in the past 7 days
• Identified as having a morning or evening chronotype according to the Morningness-Eveningness Questionnaire68
• Stable health history over the past 2 months
• Stable medication history over the past 2 months, as recommended by the primary provider
• Willing and able to provide informed consent.

Exclusion criteria

• Fasting >13 hours per day
• Actively trying to lose weight by participating in formal weight loss program or significantly restricting calorie intake
• Resting heart rate of >120 beats/minute, systolic BP >180 and/or diastolic BP >100 mmHg
• Have lost ≥ 10 pounds in last 3 months
• Self-reported exercise over 90 min/week
• Unable to wake up at a regular time between 6-9 am
• Perform overnight shift work more than 1day/week on average
• Have been diagnosed with diabetes
• On insulin or diabetes medication
• Unstable angina, heart attack or stroke in the past 3 months
• Continuous use of supplemental oxygen to manage a chronic pulmonary condition or heart failure
• Pregnant or breastfeeding
• Rheumatoid arthritis, Parkinson's disease or currently on dialysis
• Current diagnosis of a major psychiatric condition that would impair study participation
• Severe gastrointestinal disease, major gastrointestinal surgery, or active gallstone disease
• Active treatment for cancer in the past year
• Taking medications that preclude fasting for 16 hours (e.g. must be taken with food at least 12 hours apart)
• Diagnosed cognitive impairment
• Unable to fast for 16 hours.
• Any condition that in the opinion of the investigator would impair ability to participate in the trial

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Single blind

Primary purpose

Treatment

Study locations

United States · 1 center

• University of Alabama at Birmingham — Birmingham

Identifiers

NCT: NCT07634926 · IRB-300016105 · 26CDA1600914

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗