Effects of Heart Rate Variability-guided Training vs Standard Aerobic Prescription on Cardiovagal Modulation and Cardiorespiratory Fitness in Coronary Artery Disease

Summary

Coronary artery disease (CAD) is associated with autonomic dysfunction and is characterized by reduced heart rate variability (HRV) and impaired heart rate recovery. Regular exercise improves cardiovascular outcomes in CAD, with high-intensity interval training (HIIT) showing superior benefits compared to moderate-intensity continuous training (MICT). However, the full potential of exercise is not used in the clinical context since some of the training principles are neglected, contributing to a high number of exercise non-responders. HRV-guided training has been identified as an alternative prescription technique for cardiovascular endurance exercise and has contributed to greater improvements compared to standard prescriptions. Thus, this study aims to assess the chronic effects of exercise on cardiovagal modulation, baroreflex sensitivity, arterial stiffness, and cardiorespiratory fitness in patients with CAD, specifically determining whether heart rate variability-guided training yields different outcomes compared to a traditional prescription in a 12-week exercise intervention.

A total of 48 participants, will be recruited and randomized into one of 3 groups: high-intensity interval training (HIIT), moderate-intensity continuous training (MICT), and HRV-guided training. The intervention will consist of 12 weeks of supervised exercise, with 3 weekly sessions. Participants in the HRV-guided training group will have their exercise intensity adjusted based on their individual HRV profiles. Moderate- or high-intensity sessions are prescribed when the 7-day rolling average of LnRMSSD remains within the smallest worthwhile change (SWC). If it falls outside the SWC, low-intensity sessions or rest are recommended. In the HIIT group, sessions will consist of 4 bouts of 2 minutes at 80-90% HRR during the first 4 weeks, increasing to 6 bouts of 2 minutes at the same intensity in weeks 5-8, and progressing to 6 bouts of 2 minutes at 90% HRR in the final 4 weeks. In the MICT group, participants will perform continuous sessions starting with 2x10 minutes at 50-60% HRR in the first 4 weeks, progressing to 2x12 minutes at the same intensity in weeks 5-8, and increasing to 2x15 minutes at 60-70% HRR in the final phase. Cardiovagal modulation, cardiorespiratory fitness, BRS, and AS will be assessed at the baseline and after the 12 weeks of intervention.

Most cardiac rehabilitation programs use the "one-size-fits-all" approach, which is a limitation of the literature, leading to a large number of exercise nonresponders to changes in cardiorespiratory fitness. HRV-guided training seems to be a more individualized method of aerobic prescription and may lead to greater improvements in cardiorespiratory fitness and in cardiovagal modulation. This study will contribute to generate evidence regarding aerobic exercise prescription in cardiac rehabilitation.

Conditions

• Coronary Arterial Disease (CAD)

Interventions

OTHER

HIIT Intervention

Over the first 4 weeks, participants will perform 4 bouts of 2 min of high-intensity exercise at 80-90% heart rate reserve (HRR), during the next 4 weeks, participants will perform 6 bouts of 2 min of high-intensity exercise at 80-90%HRR, while in the last 4 weeks participants will perform 6 bouts of 2 min of high-intensity exercise at 90%HRR). Exercise bouts will be interspersed by 2 min of active recovery at 50-60% HRR.

OTHER

MICT Intervention

Over the first 4 weeks participants in MICT will perform continuous exercise at 50-60% HRR (2x10'), during the next 4 weeks participants will perform continuous exercise at 50-60% HRR (2x12'), while in the last 4 weeks participants will perform continuous exercise at 60-70% HRR (2x15').

OTHER

HRV-Guided Intervention

Following a 10-day initial characterization period, where the HRV is measured with plethysmography continually during the night, with "Whoop" (https://www.whoop.com) device, the individual HRV profile is defined, still, participants will use the Whoop during all intervention to allow the updating of HRV profile. Then, considering the daily individual autonomic regulation, following a decision-making schema modified from Kiviniemi et al., (2007) \[21\], exercise intensity will be defined for the training session, i.e., if LnRMSSD7day-roll-avg remained inside the smallest worthwhile change (SWC) (SWC = 0.5 × standard deviation), high intensity or moderate-intensity training sessions is prescribed, if LnRMSSD7day-roll-avg fell outside SWC, low intensity or rest is prescribed, leading to different workloads from the predefined training programs.

Sponsors & Collaborators

• Fundação para a Ciência e a Tecnologia (FCT)

  collaborator UNKNOWN

• Faculdade de Motricidade Humana

  lead OTHER

Principal Investigators

• Helena Santa-Clara, PhD · Faculdade de Motricidade Humana

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2025-09-01

Primary Completion

2027-12-01

Completion

2028-06-01

Countries

• Portugal

Study Locations