Get VO2 Max Summary by Interval
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Get VO2 Max Summary by Interval

This endpoint returns the Cardio Fitness Score (also know as VO2 Max) data for a date range. VO2 Max values will be shown as a range if no run data is available or a single numeric value if the user uses a GPS for runs. See Additional Information for further context.

The endpoint response ignores the Units header. The value returned is always in ml/kg/min.

Scope: cardio_fitness


Request

GET /1/user/[user-id]/cardioscore/date/[start-date]/[end-date].json

URI Arguments
user-id required The encoded ID of the user. Use "-" (dash) for current logged-in user.
start-date required The date in the format yyyy-MM-dd or today.
end-date required The date in the format yyyy-MM-dd or today.

Maximum range: 30 days

Request Headers
authorization required Specify the token type and Fitbit user’s access token.
Token type: Bearer
accept optional The media type of the response content the client is expecting.
Supported: application/json
accept-language optional The measurement unit system to use for response values. See Localization.
accept-locale optional The locale to use for response values. See Localization.

Examples
GET https://api.fitbit.com/1/user/-/cardioscore/date/2021-10-25/2021-11-24.json
GET https://api.fitbit.com/1/user/GGNJL9/cardioscore/date/2021-10-01/2021-10-04.json
curl -X GET "https://api.fitbit.com/1/user/-/cardioscore/date/2021-10-25/2021-11-24.json" \
-H "accept: application/json" \
-H "authorization: Bearer <access_token>"


Response

Element Name Description
cardioscore : dateTime The date specified in the format YYYY-MM-DD.
cardioscore : value : vo2Max The displayable value of VO2 Max in mL/kg/min.
{
  "cardioScore": [
    {
      "dateTime": "2021-10-25",
      "value": {
        "vo2Max": "44-48"
      }
    },
    {
      "dateTime": "2021-10-26",
      "value": {
        "vo2Max": "45"
      }
    }
  ]
}
      

Response Headers
content-type The media type of the response content being sent to the client.
Supported: application/json
fitbit-rate-limit-limit The quota number of calls.
fitbit-rate-limit-remaining The number of calls remaining before hitting the rate limit.
fitbit-rate-limit-reset The number of seconds until the rate limit resets.

Note: The rate limit headers are approximate and asynchronously updated. This means that there may be a minor delay in the decrementing of remaining requests. This could result in your application receiving an unexpected 429 response if you don't track the total number of requests you make yourself.

Response Type

HTTP Status Code HTTP response code. List of codes are found in the Troubleshooting Guide.
Status Message Description of the status code.
Response Body Contains the JSON response to the API call. When errors are returned by the API call, the errorType, fieldName and message text will provide more information to the cause of the failure.

Response Codes
200 A successful request.
400 The request had bad syntax or was inherently impossible to be satisfied.
401 The request requires user authentication.

Note: For a complete list of response codes, please refer to the Troubleshooting Guide.

Additional Information

Displaying VO2 Max data

A user’s cardio fitness score is determined by their resting heart rate, age, gender, weight, and other personal information. The user’s cardio fitness score will be shown as a range unless the user uses GPS for runs, in which case it will be returned as a single numeric value. See What is My Cardio Score? for more information.

Subscription Support for Cardio Fitness Score (VO2 Max)

VO2 Max does not support subscription notifications (webhooks). It’s worth noting that while querying VO2 Max data does not return a timestamp, VO2 Max values may change throughout the day depending on the user’s activity levels, heart rate, weight changes and other contributing factors. We recommend querying VO2 Max data once or twice a day. However, the frequency or rate at which you query VO2 Max data should be based on your specific use cases and with this in mind.

Rate limit

The VO2 Max endpoints are bound by our standard rate limit. See Rate Limits.

Device compatibility

VO2 Max data is retrieved from the user’s Fitbit account. This gives the user secure and transparent control over their data. The data is then processed and made available through the API after the user syncs their device with the Fitbit data service.

Most of the current devices sold support VO2 Max data collection. See the Fitbit Product page to determine if your specific device supports VO2 Max.