A Short Guide To Integrating Wearables

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Integrating wearables with apps can deliver a range of benefits to users.

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At Calcey, we believe that great things can happen at the intersection of business and technology. Be it in bio-tech, education, real estate, or finance, the intelligent use of technology can make things better for everyone.

Take for instance Fresh Fitness Food (FFF), a Calcey customer and a London-based startup that specialises in delivering bespoke healthy meals to suit a given caloric requirement of a customer. Every day, thousands of fitness addicts in and around London, including former England and Wasps rugby player James Haskell, depend on FFF to satisfy their nutritional requirements. 

When you are in the business of delivering healthy meals to fitness junkies, it is really important to ensure that each and every meal suits the needs and dietary preferences of EVERY SINGLE CUSTOMER. To do so, bespoke meal services usually ask customers for information such as height, weight, metabolic rate, allergies and more.

Collecting this data is often a cumbersome process. To make things worse, the human brain is notoriously bad at estimating, as many a scientist has pointed out before.

But, what about the wearables on our wrists? These tiny devices manage to gather a treasure trove of information on us with every passing day, and soon, medical professionals could use the data to even predict illnesses. Why can’t services such as FFF tap into this treasure trove of data instead of relying on inputs from customers?

Integrating wearables with apps can provide a few distinct benefits such as:

Access to real-time data

Wearables can provide apps with continuous access to a stream of real-time data, thus allowing them to deliver an optimal user experience at all times. For a custom meal service like FFF, access to real-time data will allow it to tweak meals to a customer’s shifting health attributes on a daily, weekly, or monthly basis.

Better user experiences through precise data collection

For companies and apps operating in the health-tech or fit-tech space, the data collection process is the starting point of the value chain as well as the customer journey. As such, the accuracy of this data is extremely important, and more precise data makes for a better user experience. When paired with a fitness tracker, apps such as Fitbit Coach and Nike Training Club can deliver a vastly superior experience that very closely reflects the needs of the user (based on their physical attributes) compared to when they are used in isolation and depend on user input alone.

Insurance giant AIA’s Vitality program is a great example. By integrating insurance with fitness trackers, the company can incentivize users to take care of their health and use the data to fine-tune their underwriting practices over time.

All major wearable manufacturers such as Apple, Fitbit and Garmin provide developers with access to APIs that make it a breeze to integrate wearables with web and mobile apps. Given below are the basics of what you need to know if you ever intend to integrate a wearable with an app. For the sake of simplicity, we will only be focusing on integrating the Apple Health, Fitbit, and Garmin platforms with an iOS app.

Integrating Apple Health

Of all the wearable platforms, Apple’s HealthKit platform is probably the most feature-rich and easiest to integrate. Due to its laser-like focus on privacy, Apple requires developers to obtain the explicit consent of users before accessing data. In true Apple style, the company provides developers with a set of guidelines for the purpose, and developers are expected to inform users of exactly how and why their information would be used. Typically, this can be accomplished by making amendments to the app’s Info.plist file.

HealthKit relies heavily on subclassing. At its most basic level, this is how a code snippet would look:

class HKQuantitySample : HKSample

HealthKit has several different data types of which ‘Quantity Samples’ is the most common. This data type grants access to data such as a user’s height and weight, pulse rate, etc. which can then be used by services such as FFF to build a user profile.

Here’s a sample of how the code for a query to find out the basal energy burn would look like:

guard let quantityType = HKObjectType.quantityType(forIdentifier: HKQuantityTypeIdentifier.basalEnergyBurned) else {
  fatalError("*** Unable to create a step count type ***")
// Create the query
let query = HKStatisticsCollectionQuery(quantityType: quantityType,quantitySamplePredicate: nil,options: .cumulativeSum,anchorDate: anchorDate,intervalComponents: interval)

Integrating Fitbit

Fitbit is somewhat different from Apple in that it does not allow developers to access historical data. To get around this problem, developers can use Fitbit’s Health API (now known as the Web API) 

The Fitbit API uses OAuth 2 as its authentication protocol. Since integrating a service through the OAuth 2 protocol can be messy, developers can rely on Swift’s OAuth library to complete the integration. This method should serve well in most instances and doesn’t take much time to implement as well.

Once a connection is established, the Fitbit APIs Profile and Activity endpoints (or any other endpoint) can be used to obtain the necessary data.

Here’s an example of a GET request that can be entered to obtain information about activities completed by the user:


Once processed, the API would spit out this response:

            "name":"Treadmill, 0% Incline",
            {"activity":"tracker", "distance":1.32},
            {"activity":"loggedActivities", "distance":0},
            {"activity":"veryActive", "distance":0.51},
            {"activity":"moderatelyActive", "distance":0.51},
            {"activity":"lightlyActive", "distance":0.51},
            {"activity":"sedentaryActive", "distance":0.51},
            {"activity":"Treadmill, 0% Incline", "distance":3.28}

Here’s another example of a GET request through which developers can obtain details about the user’s profile:


And the response:

    "user": {

Integrating Garmin

Unlike Fitbit, Garmin’s Health API uses OAuth 1 as its authentication protocol. Don’t worry though, because Swift’s OAuth library supports both OAuth 1 and OAuth 2 protocols.

To fetch data, developers can use the Garmin API’s Activities and Dailies classes. Here’s a sample code snippet that can be used to obtain a daily summary of the user’s activity.

Here’s the GET request:

GET api/rest/dailies?uploadStartTimeInSeconds=1452470400&uploadEndTimeInSeconds=1452556800

And here’s the response:

{ "summaryId": " EXAMPLE_67891", "calendarDate": "2016-01-11", "activityType": "WALKING", "activeKilocalories": 321, "bmrKilocalories": 1731, "consumedCalories": 1121,
"steps": 4210,
"distanceInMeters": 3146.5, "durationInSeconds": 86400, "activeTimeInSeconds": 12240, "startTimeInSeconds": 1452470400, "startTimeOffsetInSeconds": 3600, "moderateIntensityDurationInSeconds": 81870, "vigorousIntensityDurationInSeconds": 4530, "floorsClimbed": 8, "minHeartRateInBeatsPerMinute": 59, "averageHeartRateInBeatsPerMinute": 64, "maxHeartRateInBeatsPerMinute": 112, "timeOffsetHeartRateSamples": {
    "15": 75"30": 75,
     "3180": 76,
     "3195": 65,
     "3210": 65,
     "3225": 73,
     "3240": 74,
     "3255": 74
"averageStressLevel": 43, "maxStressLevel": 87, "stressDurationInSeconds": 13620, "restStressDurationInSeconds": 7600, "activityStressDurationInSeconds": 3450, "lowStressDurationInSeconds": 6700, "mediumStressDurationInSeconds": 4350, "highStressDurationInSeconds": 108000, "stressQualifier": "stressful_awake", "stepsGoal": 4500, "netKilocaloriesGoal": 2010, "intensityDurationGoalInSeconds": 1500, "floorsClimbedGoal": 18

And that’s all there is to it, really (at least from a developer’s point of view). Happy coding! 

If you are interested in finding out how we can help unleash a new wave of growth for your company with the smart use of technology, contact us via our website.