Originally Posted by carleton

It depends on the head unit that receives the data.

You can send 64 readings per second to the head unit, but if the head unit only aggregates the data into 1 second blocks and records that average, then that's all you get to see in the file when you download it.

So, it depends on the head unit more than the sensor.

For example, the Garmin 500 and SRM PowerControl 7 are both ANT+ head units. Using the same speed and cadence sensors, I can send data to both the Garmin and SRM head units. Garmin will record the average of data recorded every second, the SRM every 0.5 seconds.