By default, health check observations are conducted at an interval of 30 seconds. You can optionally select a fast interval of 10 seconds between observations.
By checking three times more often, fast interval health checks enable Route 53 to confirm more quickly that an endpoint has failed, shortening the time required for DNS failover to redirect traffic in response to the endpoint’s failure.
Fast interval health checks also generate three times the number of requests to your endpoint, which may be a consideration if your endpoint has a limited capacity to serve web traffic. Visit the Route 53 pricing page for details on pricing for fast interval health checks and other optional health check features. For more details, see the Amazon Route 53 Developer Guide.