Overview Health Data

When we talk about "health data" or "digital health data" in the context of HeartCloud, what do mean?

The answer is actually pretty simple: your iPhone has an app named "Health" (it's a white with a pink heart in the corner) that can wirelessly capture readings from other devices that in some way measure what your body is doing. For example, the Apple Watch can collect the number of steps you take, your heart beat per minute, and on newer models, GPS and electrocardiograms. Other hardware not made by Apple, like Qardio's blood pressure cuff, have sensors that the Apple Watch lacks, so it can offer even more information about how you're doing. Common to each of these examples is that what is measured about you is sent to the same place: your iPhone.

These examples of digital health data reflect careful technology choices that our company made in developing HeartCloud (for consumers/non-medical professionals) and HeartCloud for Health Practices (for physicians). Both exclusively use Apple's platform for digital health information (it's called HealthKit), meaning that HeartCloud's apps are designed for those with an iPhone and an Apple Watch.


Software Curated By Relevant Expertise

Before you scroll down and see what our apps can do with the health data on your iPhone, we wanted to point out that HeartCloud's team consists of currently practicing medical doctors and developers, systems engineers, and other technical staff with deep backgrounds in information security. The features offered by HeartCloud (web application), HeartCloud for Health Practices (web application), and HeartCloud Sync (iOS application) are directly informed by specialists with current medical knowledge, and delivered by those know live and breathe cloud technology and data protection.


Heart-Related Data Available In HeartCloud:

Data Point Source Details
Heart Rate Apple Watch
Instances of High and Low Heart Rate Events (iOS 12.2 and later) Apple Watch
Instances of Irregular Heart Rhythms (iOS 12.2 and later) Apple Watch
Heart Rate Variability[1] Apple Watch
Resting Heart Rate Apple Watch
Walking Average Heart Rate Apple Watch
Electrocardiograms (ECGs) (Apple Watch Series 4 Or Later) Apple Watch
Post-Workout Heart Rate Recovery HeartCloud. After every workout session, if you continue wearing your Apple Watch, HeartCloud will track your heart rate as it recovers up to a 15 minute period. Trends in your heart rate recovery between workouts are an important cardiovascular health metric.
Heart Rate Zones. HeartCloud. Based on your age, HeartCloud classifies every heart rate BPM value taken during a workout session in the standard 1-5 heart rate zone, but also tracks how long you stayed within each heart rate zone per workout. These trends indicate levels of cardiovascular health between workout sessions.
Tachycardia and Bradycadia HeartCloud. A search engine option lets you see the time each day your heart was in bradycardia (a heart rate of 60 beats per minute or less) or tachycardia (a heart rate of 100 beats per minute or more).
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Heart Rate

Your Apple Watch captures heart rate readings from its advanced sensors. HeartCloud beautifully visualizes that data, letting you search it, see trends, and get better insights into your cardiovascular health.


Week to Week Changes

Sometimes, the big picture matters just as much as the small details. HeartCloud gives you updates as to week-to-week changes across your various heart rate data points, allowing you to see meaningful changes in your health data over time.


Resting Heart Rate

Since a lower resting heart rate often reflects a healthier heart, HeartCloud lets you see how you're doing, day-to-day, in improving your fitness through activity and exercise.


Heart Data Search Engine

HeartCloud is like a search engine for your heart data in all of its current forms (raw heart rate, heart rate variability, resting heart rate, and walking heart rate averages). View individual minutes, hours, days, months, and years of data stored securely in your account.


Resting Heart Rate

Since a lower resting heart rate often reflects a healthier heart, HeartCloud lets you see how you're doing, day-to-day, in improving your fitness through activity and exercise.

Heart Rate Recovery

Heart Rate Recovery is a measure of how long it takes for your heart rate to return to a resting average after a workout. A minute-by-minute view broken down by minute 0 (the immediate end of your workout) to 1 minute after it, and then minutes 1-2, 2-3 , 3-4, and 4-5 after that.

A 15 minute "bigger picture" view of minute 0 to 15 minutes after your workout features a horizontal line that displays your average heart rate over the last 30 days. This provides an accurate baseline to measure your heart rate recovery period as your body cools down over a longer period of time after a workout.


Why Just Apple Watch?

A study published in the Journal of the American Medical Association found that the Apple Watch was the most accurate of wrist-worn smartwatches.

The Apple Watch captures:

  • Regular heart rate

  • Heart rate variability

  • Resting heart rate

  • Heart rate during sleep

  • Workout Data

  • Post-workout heart rate recovery

HeartCloud is a secure web application that visualizes your Apple Health data. You can search it, see trends, compare health data between time periods of your choice, and get better insights into your cardiovascular health.

VO2 Max

VO2max is a rate that exercise physiologists use to measure what volume of oxygen your body can use per minute, when you're active at your maximum effort. It is represented in ml (of oxygen used) per kg (of body weight) per minute. Many factors go into this, including how much oxygen your red blood cells can carry, your gender (men on average have higher values), cardiovascular and pulmonary health, musculoskeletal fitness, and others. Higher numbers tend to reflect better fitness, and generally this can be increased by a program of regular aerobic exercise. Classically, VO2max is measured in the lab, while a person runs on a treadmill and inspired and exhaled gas is measured along with EKG. The Apple Watch can estimate your VO2max based upon heart rate data.

Read More about VO2 Max.


Blood Pressure

As amazing as the Apple Watch is, it lacks certain sensors that other third party health devices offer (like the ability to measure blood pressure). One of HeartCloud's unique features is that you can import data not gathered by the Apple Watch.

Blood pressure is a critical health metric. Our graphs and timelines display blood pressure measurements over time, which let you examine broader trends.




Each blood pressure reading is presented on a timeline where each timeline item is a single day and each day is sorted from latest to earliest. Any blood pressure reading, like the 140/75, indicating various stages of hypertension are marked in red so as you scroll, you can visually separate more normal from more concerning readings.

What Readings Mean

HeartCloud classifies every blood pressure reading (hypertensive (stage 1 or 2), hypotensive, elevated, or normal) according to widely-respected sources which gives you more informative context as to changes over time. You can see your blood pressure history in the context of what the Centers for Disease Control and Prevention classifies as stages of blood pressure risk.



Dexcom glucose readers are capable of writing data to Apple's Healthkit, and therefore HeartCloud can intake and interpret that data.



Glucose + Heart Rate

While your Apple Watch is worn, heart rate data is captured. At the same time, glucose readings are taken throughout the day. HeartCloud can show you (or your doctor, through HeartCloud for Organizations) the relationships between heart rate and glucose readings on a day-by-day basis.

Glucose Events

Each day, glucose serum levels hit certain maximum and minimum points. HeartCloud lets you see not just what your daily maximum and minimum values were, but at what times (and how many times) these occurred.


Weight and BMI

HealthKit-compatible digital weight scales measure body mass and can sync that data to your iPhone's Health App. Some of these scales also capture BMI (body mass index) readings. HeartCloud allows you to import these data points, letting you track your weight in conjunction with changes in blood pressure or various heart-related data.

In addition, if your physician uses HeartCloud for Health Practices, taking weight measurements at various times of the day leading up to or after a surgical procedure can furnish helpful data that allows for more personalized, remote, and better health care at home.


Electrocardiograms From Apple Watch Series 4

The Apple Watch Series 4 introduced the ability to take an ECG right from your wrist, anytime and anywhere. Capitalizing on this incredible advancement, we wanted to add some novel ways of exploring and sharing these readings.

Each ECG is presented on a timeline from latest to earliest. Each reading is color-coded according to the result: red for atrial fibrillation and green for sinus rhythm. Other colors indicate various reasons why the results could not be classified, which may include a heart rate that was too high during the reading or that no conclusion could be drawn.


Explore Each One

You can also click on any ECG measurement and explore it in detail. This includes details on the date and time in which it was recorded and more scientific information like the sampling rate and unit of measure.

If you decide to use HeartCloud's built-in data sharing features, your doctor can see each reading. All ECG data is securely encrypted and sharing with your physician omits the need to e-mail a PDF file (or know how to encrypt a PDF attachment, as e-mail is not necessarily the most secure means of online communication).


In Search Results

A core feature of HeartCloud is the ability to graph relevant data in easy-to-read ways on easy-to-understand charts. So if you search your data and include heart rate as part of what you search for, the date and time of electrocardiograms taken with the Apple Watch that fall within the date(s) and times you searched within are marked on the heart rate graph with vertical lines. This lets you examine an ECG classification in relation to how your heart was acting before, during, and after the ECG was taken.