Abstract

Background Cardiovascular disease (CVD) prevention is limited by the major challenge of low long-term adherence to effective lifestyle regimens. Arterial stiffness (measured by carotid-femoral pulse wave velocity, cfPWV) and maximal cardiorespiratory fitness (measured by VO2max), are modifiable risk factors for CVD but require sustained lifestyle change. Wearable technology provides continuous measurement and offers a scalable platform to deliver health interventions. A combination of continuous monitoring with a wearable device and an artificial intelligence (AI) -based coach personalized for individual data and preferences could be a powerful, low-barrier tool for achieving sustainable cardiovascular health benefits by directly addressing the adherence challenge.

Objective We will study the comparative effectiveness of a wearable and an interactive app-based AI coaching intervention promoting moderate exercise on improving gold-standard cfPWV and VO2max. This will be compared to a supervised high-intensity interval training (HIIT) group (benchmark with known benefits for VO2max) and a control group using only Oura Ring (passive monitoring). We will also conduct a detailed Process Evaluation (structured interviews) to study the feasibility and experience of interacting with the AI coach.

Methods This randomized controlled trial recruited 165 eligible sedentary participants aged 30-65 years. Co-primary outcomes cfPWV and VO2max were measured at baseline and will be repeated after 12 weeks. Participants were equally randomized into three groups: an AI-based coaching group (steady-state exercise), a HIIT group (supervised exercise) and a control group (usual low activity). The AI-based coaching group receives personalized guidance using large language model (LLM) technology. All participants wear Oura Ring and are blinded to cardiovascular health metrics provided by the ring.

Results The recruitment for the study began in October 2024 and will end when 165 men and women have been recruited. Data collection for the study is scheduled to conclude early 2026. Data collection is ongoing.

Conclusions This study will evaluate if a highly scalable, AI-based coaching intervention can achieve comparable gains in CV structural health (cfPWV) and functional capacity VO2max relative to a resource-intensive supervised HIIT benchmark. The findings will provide essential evidence on the use of digital health tools to promote sustainable exercise adherence.

Competing Interest Statement

All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf and declare: SS, JK, AR, HS, DC and PO declare competing financial interests in the form of ongoing salaried employment and employee equity at Oura Health Oy (Oulu, Finland) and MdZ at Ouraring Inc (San Francisco, CA, United States) or any of their affiliates. HP, SH, PK and KS declare no financial relationships with any organizations that might have an interest in the submitted work in the previous three years. All authors declare no other relationships or activities that could appear to have influenced the submitted work.

Clinical Trial

NCT06644014

Funding Statement

This study was funded by Oura Health Oy (Oulu, Finland)

Author Declarations

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

Approval granted by Regional Medical Research Ethics Committee of Eastern Finland Collaborative Area

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Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

Data Availability

All data produced in the present study are available upon reasonable request to the authors; pending additional consent from the participants

AbbreviationsAIartificial intelligenceCVAcardiovascular ageHIIThigh-intensity interval trainingPWVpulse wave velocityRCTRandomized controlled trial