Hair is compromised even by the elements (sun, wind, heat, cold, etc.). Your goal is to do your best to minimize damage by understanding what your hair needs. There is no need to blow dry hair everyday. You should be able to maintain a style without the need to re-dry it or re-wash it. Do you have the correct equipment?
Cold air doesn’t smooth the cuticle when you are drying the hair. Cold air sets the style, for example if you are blowing the hair and setting on rollers or pinning in place, a shot of cold air helps to set the shape.
Overuse of hot air can cause damage to the hair strand if the hot air stays in one place too long, keep the dryer and the brush moving and not directly close to the hair.
Hair dryers have improved and are equipped to minimize static, decrease drying time, eliminate frizz, add shine and so forth. Even with all the improvements you must respect the hair strands and the current condition of your hair.
There are many factors to determine hair loss or are you thinking of hair breakage? Hair loss is associated with damage done to the bulb which is located at the bottom of the hair follicle. Breakage is associated with splintering, split ends, pieces or halves that are noticed when you inspect the hair.