The Impact of Exercise Intervention on Biological and Functional Aging Through the Lens of Epigenetic Clocks

Summary

This study investigated the effects of a structured 6-month high-intensity interval training (HIIT) program on blood DNA methylation-based measures of biological ageing, physical fitness, cardiovascular function, body composition, metabolic health, and the gut microbiome in adults aged 50-70 years.

Participants completed supervised exercise training three times per week for 6 months. Exercise intensity was individually prescribed based on estimated maximal heart rate (HRmax) and continuously monitored using Polar H10 heart-rate sensors. Perceived exertion was also assessed using the Borg Rating of Perceived Exertion scale to support safe and appropriate exercise intensity. The training program progressively increased the amount of high-intensity exercise over the intervention period. High-intensity intervals were performed above approximately 80% of estimated HRmax and were separated by 2-minute periods of active recovery.

Before and after the intervention, participants underwent physiological and functional assessments. Cardiovascular function was evaluated using echocardiography. Aerobic capacity was assessed using spiroergometry and the Chester Step Test for estimation of VO₂max. Muscular performance was evaluated using maximal vertical jump and handgrip strength tests. Exercise volume was quantified using oxygen-consumption and heart-rate data collected during exercise and expressed as MET-hours (MET-hrs), allowing the individual exercise dose accumulated during the intervention to be characterized.

Body composition was assessed using dual-energy X-ray absorptiometry (DEXA). Measurements included total and regional fat mass and fat-free mass, allowing changes in overall and regional body composition to be evaluated.

Blood samples were collected before and after the intervention, with participants refraining from exercise for 48 hours before blood collection. Samples were analyzed for selected metabolic and clinical biomarkers, including glucose, triglycerides, total cholesterol, HDL cholesterol, LDL cholesterol, and liver enzymes.

Blood samples were also used to assess blood DNA methylation-based measures of biological ageing. Genome-wide DNA methylation was measured using the Illumina Infinium MethylationEPIC BeadChip. Several DNA methylation-based ageing measures were calculated, including DNAmFitAge, DNAmPhenoAge, DNAmGrimAge, Hannum Age, DunedinPACE, and the Horvath Skin \& Blood and pan-tissue clocks. Changes in biological age acceleration were evaluated between baseline and post-intervention.

The gut microbiome was characterized using shotgun metagenomic sequencing to assess changes in microbial composition and functional potential following the exercise intervention.

The primary overall objective of the study was to determine whether the individual volume of exercise performed, quantified as MET-hours, was associated with changes in blood DNA methylation-based biological age acceleration following the 6-month intervention. The study also examined whether exercise volume and training-related changes were associated with changes in physical fitness, cardiovascular function, body composition, metabolic biomarkers, and gut microbiome characteristics. The results may contribute to understanding whether the amount of regular high-intensity exercise is related to biological ageing and other physiological adaptations in 50\< years old adults.

Conditions

• Age Over 50 Years

Interventions

OTHER

Exercise - Relative High-Intensity Interval Training (HIIT)

Participants completed supervised high-intensity interval training (HIIT) 3 times weekly for 6 months. Exercise intensity was prescribed relative to estimated maximal heart rate (HRmax; Tanaka formula) and was monitored continuously using Polar H10 heart-rate sensors. Sessions included a progressive warm-up, repeated 2-minute high-intensity intervals performed above 80% of HRmax, and 2-minute active recovery periods. Perceived exertion was also monitored using the Borg 0-10 RPE scale, with an upper target of 8. The protocol progressively increased training load: sessions 1-25 included five high-intensity intervals, sessions 26-45 six intervals, and sessions 46 onward seven intervals. Session duration increased from 34 to 38 minutes in the final phase.

Sponsors & Collaborators

• Semmelweis University

  collaborator OTHER

• Hungarian University of Sports Science

  lead OTHER

Study Design

Allocation

NA

Purpose

BASIC_SCIENCE

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

50 Years

Max Age

70 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2022-05-01

Primary Completion

2024-05-01

Completion

2024-06-30

Countries

• Hungary