Network failover load

I would be hesitant using a link that avg. 50% busy for the HA heart beat. A link utilization of 50% means that you are running at 100% for half of the time. You can't transmit data at 500 Mbps on a 1Gbps link. When data is flowing over a link it is running at 100%. So if for a 5 minute interval you show 50% utilization, that means for a total of 2.5 minutes you were running at 100% and for a total of 2.5 minutes you were running at 0%.