I've heard SF training called a "torture course", but is it true you are actually tortured in the SERE phase?

I've heard that soldiers are conditioned to withstand torture like waterboarding and other things, so that they know what to expect and can overcome it in a real scenario. Does anyone know if this is true? I know in the British SAS and Russian Spetznas it is, but I've never heard anything about SF. Supposedly they are designed from experiences american POWs had in Iraq and Vietnam