Most of the time in America wrestling sessions end in conditioning and total exhaustion of the wrestlers. The training in Russia (drilling and wrestling) is very frequent but it is more like play. You come in, drill and wrestle live until you feel tired. Then you leave and come back as soon as you get some energy back, which is usually later in the day. Its basically called living in the wrestling room but here is the important part. Rather than getting in shape from doing conditioning so much, they get in shape UNCONSCIOUSLY by drilling and wrestling so frequently.

Also, there is something called efficiency vs conditioning. The more efficient you are with moves, the less conditioning you need to wrestle well.