There have been some blogs written about this, most of them ill-informed. Research shows that collagen only begins to be broken down or "denature" at 150°C (1). That's 50°C above the boiling temperature of water! People drink coffee and other hot beverages at 70-85°C (90°C max.), so in practical everyday terms you don’t need to worry about heat affecting your collagen.
Referenced sources:
Bozec, L, Odlyha, M, et al (2001). Thermal denaturation studies of collagen by microthermal analysis and atomic force microscopy.