Is it true that an air conditioning unit dries the atmosphere and it is not hygiene?

During the heating mode, the out coming air from the indoor unit has a temperature of 40°C approximately. At this temperature the relative humidity becomes very low (35% to 40%). That is why the heated air should be directed long from the place that a human is sleeping or resting, so as to be given enough time to the heated air to be mixed with the room air and to reach the normal temperature and humidity. The small room air conditioning units do not have the capability of humidifying the air, as it happens with the central units.