ContentView.swift

func readHourlyTotalStepCount() {
        guard let stepCountType = HKObjectType.quantityType(forIdentifier: .stepCount) else {
            fatalError("*** Unable to get the step count type ***")
        }
        
        var interval = DateComponents()
        interval.hour = 1
        
        let calendar = Calendar.current
        let anchorDate = calendar.date(bySettingHour: 0, minute: 55, second: 0, of: Date())
        
        let query = HKStatisticsCollectionQuery.init(quantityType: stepCountType,
                                                     quantitySamplePredicate: nil,
                                                     options: .cumulativeSum,
                                                     anchorDate: anchorDate!,
                                                     intervalComponents: interval)
        
        query.initialResultsHandler = { query, results, error in
            let startDate = calendar.date(byAdding: .hour,value: -24, to: Date())
            
            results?.enumerateStatistics(from: startDate!,to: Date(), with: { (result, stop) in
                print("Time: \(result.startDate) -\(result.endDate), \(result.sumQuantity()?.doubleValue(for: HKUnit.count()) ?? 0)")
            })
        }
        healthStore.execute(query)
    }