I guess so. About 14 years ago, I ran CPU intensive software that pegged the CPU usage at 100% constantly for many hours. Didn't have any problem back then. That was a Pentium III CPU. I know newer CPUs generate a lot more heat than the old ones.
I'm currently using a Q6600 quad core at home. Never had any system lock-up or hardware failure due to overheating. I don't run any CPU intensive processes for hours anymore. Perhaps when I upgrade to i7, I will consider reapplying thermal paste after removing/reinstalling heat sink.
Back in PIII days, the cpu "could" have fried itself.. but not likely...the system would just crash/freeze. An AMD would have fried.
Nowadays, the CPU will just throttle.(running at 2.00GHz vs. 2.4 for ex. on your Q6600, and run 100% at that speed). This is a big problem with the K model Haswells; they need 1.3+ vcore to run at 4.6GHz+, but will just throttle.. leaving you with less power.