When vampires (& Chris) move at super speeds, their brain functions also have to accelerate to coordinate the body’s movement. To be able to move so fast as to leave a collapsing air bubble behind you when you disappear at one spot & stop at another would need at least an order of magnitude speed increase or more, with an associated increase in neuron firing speeds. The brain takes up 2-3% of our body weight, but uses about 20% of our body’s energy. Jack that up by an order of magnitude & the calorie requirements get surreal. Plus all that energy burn goes to heat output.
It doesn’t mean much if Tanya blurs across a room to get in someone’s face, but sustained combat would be something else entirely. Vampires normally run a bit cool, but in a sparring session between Tanya & Arkady, Arkady was sweating rivers trying to keep up with Tanya. Most of that sweat should be his body trying to keep his brain from frying. Yes the V2 will be repairing damage, but very high body temperatures inhibit & kill viruses, so a vampire (or Chris) would try & keep sustained combat to a minimum. Tanya would be heating up as well, but stronger vamps tolerate the heat buildup better. It might be the reason for vampires lower body temperature, the V2 providing a “temperature buffer” for emergencies. Looking at them in infra red, in combat their body temperature would be considerably higher & their heads would look like light bulbs. Their heart rates should be higher as well (able to be detected) to move blood around cooling the brain. Chris’s fight with the duelist should have had them both near the point of a heat stroke. This would affect weres to a lesser degree, since they don’t move as fast as older vamps. Perhaps in one of the Compendium 3 stories, Dr. Singh is addressing this subject in a side note during practice.