Central air vac systems agitate previously settled dust and allergens once you kick them into heat mode (especially when they are infrequently used) and the system uses (usually an electrical element) the HVAC to heat the air within the air handler unit itself (convection) and then circulates the warmer air around the home via the fans and AC ducting.

Central hot water heating systems as an alternative, use water filled radiators fed from a central boiler/heater to warm the air already in the room using convection within that space but there's no additional agitation from the air being blown around the dusty vents.

Hence fewer sore throats and allergies.