diff --git a/packages/@aws-cdk/aws-applicationautoscaling/lib/target-tracking-scaling-policy.ts b/packages/@aws-cdk/aws-applicationautoscaling/lib/target-tracking-scaling-policy.ts
index 053dca7f4f289..f2f2a5bed2dfe 100644
--- a/packages/@aws-cdk/aws-applicationautoscaling/lib/target-tracking-scaling-policy.ts
+++ b/packages/@aws-cdk/aws-applicationautoscaling/lib/target-tracking-scaling-policy.ts
@@ -35,14 +35,24 @@ export interface BaseTargetTrackingProps {
   /**
    * Period after a scale in activity completes before another scale in activity can start.
    *
-   * @default - No scale in cooldown.
+   * @default Duration.seconds(300) for the following scalable targets: ECS services,
+   * Spot Fleet requests, EMR clusters, AppStream 2.0 fleets, Aurora DB clusters,
+   * Amazon SageMaker endpoint variants, Custom resources. For all other scalable
+   * targets, the default value is Duration.seconds(0): DynamoDB tables, DynamoDB
+   * global secondary indexes, Amazon Comprehend document classification endpoints,
+   * Lambda provisioned concurrency
    */
   readonly scaleInCooldown?: cdk.Duration;
 
   /**
    * Period after a scale out activity completes before another scale out activity can start.
    *
-   * @default - No scale out cooldown.
+   * @default Duration.seconds(300) for the following scalable targets: ECS services,
+   * Spot Fleet requests, EMR clusters, AppStream 2.0 fleets, Aurora DB clusters,
+   * Amazon SageMaker endpoint variants, Custom resources. For all other scalable
+   * targets, the default value is Duration.seconds(0): DynamoDB tables, DynamoDB
+   * global secondary indexes, Amazon Comprehend document classification endpoints,
+   * Lambda provisioned concurrency
    */
   readonly scaleOutCooldown?: cdk.Duration;
 }