hi sir, sending data to cayenne at rapid rate (1 second) is not advisable as it can cause the device to disconnect or blocked. the inbuilt CAYENNE_OUT_DEFAULT() sends data at every 15 seconds interval. if you want you can millis() to send data at even faster rate but just keep in mind not to hit the rate limit of 60 messages each minute.
to know more have a look at this topic Sending MQTT messages within rate limits