diff --git a/RCTAppleHealthKit/RCTAppleHealthKit+Queries.m b/RCTAppleHealthKit/RCTAppleHealthKit+Queries.m
index bdb19107f3c5518c557c5bc81e8024528e1f82c9..d849d0561d8d35a9c944577cd26c0cb4f84b6f4a 100644
--- a/RCTAppleHealthKit/RCTAppleHealthKit+Queries.m
+++ b/RCTAppleHealthKit/RCTAppleHealthKit+Queries.m
@@ -79,8 +79,8 @@
                     HKQuantity *quantity = sample.quantity;
                     double value = [quantity doubleValueForUnit:unit];
 
-                    NSString *startDateString = [RCTAppleHealthKit buildISO8601StringFromDate:sample.startDate];
-                    NSString *endDateString = [RCTAppleHealthKit buildISO8601StringFromDate:sample.endDate];
+                    int startDateTimestamp = [RCTAppleHealthKit buildTimestampFromDate:sample.startDate];
+                    int endDateTimestamp = [RCTAppleHealthKit buildTimestampFromDate:sample.endDate];
                     
                     NSString *deviceName = sample.device.name ? sample.device.name : @"";
                     NSString *deviceManufacturer = sample.device.manufacturer ? sample.device.manufacturer : @"";
@@ -98,8 +98,8 @@
                     
                     NSDictionary *elem = @{
                             @"value" : @(value),
-                            @"startDate" : startDateString,
-                            @"endDate" : endDateString,
+                            @"startDate" : @(startDateTimestamp),
+                            @"endDate" : @(endDateTimestamp),
                             @"deviceName" : deviceName,
                             @"deviceManufacturer" : deviceManufacturer,
                             @"deviceHardware" : deviceHardwareVer,
@@ -166,25 +166,10 @@
                     // HKCategoryType *catType = sample.categoryType;
                     NSInteger val = sample.value;
 
-                    // HKQuantity *quantity = sample.quantity;
-                    // double value = [quantity doubleValueForUnit:unit];
-
-                    NSString *startDateString = [RCTAppleHealthKit buildISO8601StringFromDate:sample.startDate];
-                    NSString *endDateString = [RCTAppleHealthKit buildISO8601StringFromDate:sample.endDate];
+                    int startDateTimestamp = [RCTAppleHealthKit buildTimestampFromDate:sample.startDate];
+                    int endDateTimestamp = [RCTAppleHealthKit buildTimestampFromDate:sample.endDate];
 
                     NSString *valueString = [NSString stringWithFormat:@"%d", val];
-
-//                    switch (val) {
-//                      case HKCategoryValueSleepAnalysisInBed:
-//                        valueString = @"INBED";
-//                      break;
-//                      case HKCategoryValueSleepAnalysisAsleep:
-//                        valueString = @"ASLEEP";
-//                      break;
-//                     default:
-//                        valueString = @"UNKNOWN";
-//                     break;
-//                  }
                     
                     NSString *deviceName = sample.device.name ? sample.device.name : @"";
                     NSString *deviceManufacturer = sample.device.manufacturer ? sample.device.manufacturer : @"";
@@ -202,8 +187,8 @@
 
                     NSDictionary *elem = @{
                             @"value" : valueString,
-                            @"startDate" : startDateString,
-                            @"endDate" : endDateString,
+                            @"startDate" : @(startDateTimestamp),
+                            @"endDate" : @(endDateTimestamp),
                             @"deviceName" : deviceName,
                             @"deviceManufacturer" : deviceManufacturer,
                             @"deviceHardware" : deviceHardwareVer,
@@ -222,22 +207,9 @@
         }
     };
 
-    // HKSampleQuery *query = [[HKSampleQuery alloc] initWithSampleType:quantityType
-    //                                                        predicate:predicate
-    //                                                            limit:lim
-    //                                                  sortDescriptors:@[timeSortDescriptor]
-    //                                                   resultsHandler:handlerBlock];
-
     HKCategoryType *categoryType =
     [HKObjectType categoryTypeForIdentifier:HKCategoryTypeIdentifierSleepAnalysis];
 
-    // HKCategorySample *categorySample =
-    // [HKCategorySample categorySampleWithType:categoryType
-    //                                    value:value
-    //                                startDate:startDate
-    //                                  endDate:endDate];
-
-
    HKSampleQuery *query = [[HKSampleQuery alloc] initWithSampleType:categoryType
                                                           predicate:predicate
                                                               limit:lim
@@ -249,17 +221,6 @@
 }
 
 
-
-
-
-
-
-
-
-
-
-
-
 - (void)fetchCorrelationSamplesOfType:(HKQuantityType *)quantityType
                                  unit:(HKUnit *)unit
                             predicate:(NSPredicate *)predicate
@@ -287,13 +248,13 @@
             dispatch_async(dispatch_get_main_queue(), ^{
 
                 for (HKCorrelation *sample in results) {
-                    NSString *startDateString = [RCTAppleHealthKit buildISO8601StringFromDate:sample.startDate];
-                    NSString *endDateString = [RCTAppleHealthKit buildISO8601StringFromDate:sample.endDate];
+                    int startDateTimestamp = [RCTAppleHealthKit buildTimestampFromDate:sample.startDate];
+                    int endDateTimestamp = [RCTAppleHealthKit buildTimestampFromDate:sample.endDate];
 
                     NSDictionary *elem = @{
                       @"correlation" : sample,
-                      @"startDate" : startDateString,
-                      @"endDate" : endDateString,
+                      @"startDate" : @(startDateTimestamp),
+                      @"endDate" : @(endDateTimestamp),
                     };
                     [data addObject:elem];
                 }