Is white water rafting physically difficult?

[CuplACruzrs]

My DH and I would really like to go white water rafting while in Costa Rica but I have concerns. I had spinal fusion of 2 disks in my neck last May. The neurosurgeon says I am completely healed at this point but at "increased risk" due to my fusion. His concern is whiplash, compression, etc. I have never rafted before so I dont know if this is an issue or not. Sure if I get tossed out of the raft, hit my head on a rock, I would expect serious results. But are the general ups and downs of the current and rapids extremely taxing on your back or neck? Did you feel like your head was doing a dance on your neck? Do you need a lot of upper body stength for paddling?

 

Also, what about the ziplining? I know that you use your stomach muscles a lot but what about your neck muscles?

 

I really dont want to do the drive throughs but will if we have to.