Obtain current heart rate Samsung health

I am trying to get the current heart beat rate using Samsung health. I am using Samsung's SDK for Android basing my code on the example provided to count the steps. Here is how I adapted the code for some tests I did at 6pm:

HealthDataResolver resolver = new HealthDataResolver(mStore, null);

// Set time range from start time of today to the current time
long startTime = 16 * 60 * 60 * 1000;
long endTime = startTime + 2 * 60 * 60 * 1000;
HealthDataResolver.Filter filter = HealthDataResolver.Filter.and(
        HealthDataResolver.Filter.greaterThanEquals(HealthConstants.HeartRate.START_TIME, startTime),
        HealthDataResolver.Filter.lessThanEquals(HealthConstants.HeartRate.END_TIME, endTime));

HealthDataResolver.ReadRequest request = new ReadRequest.Builder()
            .setDataType(HealthConstants.HeartRate.HEALTH_DATA_TYPE)//.setDataType(HealthConstants.StepCount.HEALTH_DATA_TYPE)
            .setProperties(new String[] {HealthConstants.HeartRate.HEART_RATE})
            .setLocalTimeRange(
                HealthConstants.StepCount.START_TIME,
                HealthConstants.StepCount.TIME_OFFSET,
                startTime, endTime)
            .setFilter(filter)
            .build();

try {
    resolver.read(request).setResultListener(mListener);
} catch (Exception e) {
    Log.e(MainActivity.APP_TAG, "Getting step count fails.", e);
}

So basically, the problem is that originally, the steps code meassured the interval of the whole day (endTime = startTime + ONE_DAY_IN_MILISECONDS). I tried to adapt this code to obtain the heart beat average of the last 20 seconds, but when I shrink the margin between the startTime and the endTime to an interval lower than one hour, the average I retrieve is zero. Therefore, my question is: is this the right way to obtain the current heart beat? If so, what I am doing wrong or how can this be achieved?

I finally found the answer. Samsung Health updates it's data with a very low frequency. That cannot be changed and therefore, when trying to access to small time intervals, it does not find any register and retrieves a zero value. The correct way to do this is to directly connect to the wristband via BLE using the Samsung SDK for Devices. There are a bunch of guidelines in order to obtain the different meassurements. For this case, it should be used the Heart Rate Monitor Guide.