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Welltory is the Ultimate HRV App


Science behind Welltory

Welltory is comprised of a team of developers and scientists who work with the scientific community to create a healthcare app designed for personalized disease prevention. We provide users with biofeedback based on their quantified data and our proprietary algorithms for heart rate variability analysis. Our contribution to the global scientific community also extends into our partnership program for universities and independent scientists with whom we share access to the Welltory app’s advanced scientific features.

Our approach is based on decades of scientific research.

Welltory analyzes heart rate variability (HRV) — a health marker backed by over 25,000 studies on PubMed.

Heart rate variability is a trusted health assessment method. First designed to track astronaut performance in the 1960s, HRV analysis quickly gained a reputation as a reliable health assessment method applicable to fields like healthcare, high-performance sports, and military training.

Today, HRV is used by researchers, healthcare professionals, and pro athletes to track stress, recovery, systemic inflammation, and overall nervous system balance.

Our research team designs professional methods to analyze Photoplethysmography (PPG) measurements of heart rate variability using a phone camera. Their results were presented at professional conferences and in academic publications.



is a technique used to detect blood volume changes caused by the heartbeat — a light source illuminates the skin while the device measures changes in light absorption.



measurements read electric signals from the heart and require a chest strap with electrodes placed close enough to the heart to pick up the signals.

Welltory supports both PPG and ECG measurements taken with BLE heart rate monitors like Polar, Apple Watch, Samsung HRM, and even your phone’s camera.

Recent research (April 2022) proved that Welltory is a valid and reliable smartphone application and can be used to monitor HRV in elite endurance athletes.

HRV measurements taken with Apple Watch have been validated with the Polar H7 chest strap along with Samsung HRM — the PPG-based heart rate monitor on the back of Samsung phones.

The accuracy of measurements taken with a smartphone camera has been proven — such measurements are on par with the Polar H7 chest strap. We’ve also published research on our HRV signal processing and quality assessment method, and have presented our findings at the 41st International Engineering in Medicine and Biology Conference in Berlin.

With the growing popularity of wearable devices, we realized that we could collect additional bio-data for a correlational analysis of users’ HRV measurements. As such, our team of scientists and developers has updated the Welltory app. In the new version of the app, users can sync their smartwatches and other health apps. Not only are we now collecting data on pacing, steps, workouts, VO2max, sleeping heart rate, and more, but can also provide users lifestyle patterns based on this data. Every year our team improves the quality of the database in parallel with the growing body of research.

Our research activities

We conduct research to explore new possibilities for personalized health care advice. Our team of scientists conduct research in two areas.


We publish scientific papers in which we examine collected data.

We contribute to future advancements in scientific research by sharing our anonymous data with the scientific community.

For instance, in 2020, Welltory launched an open data research project aimed at identifying diagnostic patterns of COVID-19-inflicted disease detection, progression, and recovery. As part of the research, our users with a positive COVID-19 status tracked their symptoms, heart rate variability, and data with the Welltory app using wearables such as the Apple Watch, Garmin, or Fitbit. We released a collected data set to researchers were studied patterns that ought to predict symptoms and published their findings.

This study was free of commercial motives from the get-go; it began with a collaborative spirit and recognition of the potential for a meaningful contribution to the field of virology.

Heart Rate Variability as a Prospective Predictor of Early COVID-19 Symptoms

Amity University; Noida, India; Woosong University; Daejeon, Korea; Hankuk University of Foreign Studies; Seoul, Korea | Pre-Emption of Affliction Severity Using HRV Measurements from a Smart Wearable; Case-Study on SARS-Cov-2 Symptoms

Our team developed an algorithm to reduce noise from a PPG signal — the most complex task in a photoplethysmography (PPG) analysis. We describe our methodology in the following research paper:

Wavelet Analysis and Self-Similarity of Photoplethysmography Signals for HRV Estimation and Quality Assessment


We research our users' data and create unique new features that help them stay healthy

The Welltory app is the result of synergy between developers and scientists who keep up with the latest research, technology, and publications in their field of work. Equipped with the power of science, we create new unique features, analyze gathered data, and contribute to the global scientific community in sharing the outcomes of our work.

We employ a unique approach to data processing: we track users’ mood scales during daily activities in addition to basic information like step counts, sleep patterns, number of workouts, etc.

For instance, studies based on our users’ data have proven that Welltory serves as a reliable stress measurement aid.

Smartphone App Stress Assessments: Heart Rate Variability vs Perceived Stress in a Large Group of Adults

This paper examined the relationship between HRV-based physiological stress responses and Perceived Stress Questionnaire self-assessments to validate Welltory measurements as daily stress measurement tools.

As a result of the contributions made by Welltory scientists, users are able to measure stress using their heart rate variability measurements.

A Welltory integration will allow you to collect data for the following metrics:

  • Stress
  • Energy
  • Productivity
  • Resilience
  • Balance
  • Coherence
  • RMSSD index
  • SDNN index
  • Total power

Our research cycle consists of 4 steps:

  1. Accumulate data through third-party apps and devices.
  2. A meta-analysis of wellness and health research. We formulate and validate the hypothesis. We search for patterns and correlations in the data. And we build new algorithms based on our findings.
  3. Build smart algorithms into new Welltory app features.
  4. Collect new data with the help of new features and personalized information. And then a new research cycle begins.

Welltory in the global scientific community

Our company prioritizes its contributions to global research initiatives. That’s why our partnerships with universities and research teams are important to us. We conduct our own research, collaborate with research groups and universities all over the world, and lead open-source research projects.

Check out our partner universities' research papers conducted with the help of the Welltory app:

University College London

Knowing What You’re Doing or Knowing What to Do: How Stress Management Apps Support Reflection and Behaviour Change

Action Planning and Coping Planning: The Effects of Guided Reflection in Personal Informatics on a Successful Behaviour Change

Get Moving to Manage Stress: how wellbeing self-tracking apps can support exercise behaviour change for people experiencing stress

Texas University

Therapy Dog Effects on Nursing Student Stress: A Mixed Methods Study

Arizona State University

Heart-Focused Breathing and Perceptions of Burden in Alzheimer's Caregivers: An Online Randomized Controlled Pilot Study

Welltory was quoted by

Project MUSE - The Data-Based Self: Self-Quantification and the Data-Driven (Good) Life

The Quantified Self and the Digital Making of the Subject from The Digital Age and Its Discontents: Critical Reflections in Education on JSTOR

Open Affect-Responsive Systems: Toward Personalized AI to Beat Back the Waves of Technostress

Mobile Healthcare Application for Breathing Training Monitoring and Gamification in Heart Rate Variability for Well-Being

Comparative Heart Rate Variability Analysis of ECG, Holter and PPG Signals

Proceedings of the Future Technologies Conference (FTC) 2021, Volume 2

Validity and reliability of different smartphones applications to measure HRV during short and ultra-short measurements in elite athletes

Alternation of the Autonomic Nervous System Is Associated With Pulmonary Sequelae in Patients With COVID-19 After Six Months of Discharge

Wearable Devices, Smartphones, and Interpretable Artificial Intelligence in Combating COVID-19

Persistent bradycardia in post-COVID-19: Possible dysautonomia? A case report

Chronotropic Incompetence in Non-Hospitalized Patients with Post-COVID-19 Syndrome

* That’s why Welltory is celebrated as a global research hub and leading company in the field of mobile health.

Links to official resources

Body performance

Mind State