What should be avoided to prevent damaging hair during a blowout?

Using high heat without protection is essential to prevent damaging hair during a blowout because excessive heat can cause the hair cuticle to lift and lead to moisture loss, resulting in dryness, brittleness, and breakage. When hair is exposed to high temperatures without a protective barrier, like a heat protectant spray, the risk of damaging the hair increases significantly. Proper heat protection products can coat the hair shaft, minimizing damage and helping to maintain the hair's health and shine.

Understanding the context of the other options can enhance your knowledge. Blow drying wet hair can lead to damage, especially if the hair is not in the best condition, as it can make the hair more susceptible to damage. Using a round brush is a common technique to achieve a smooth finish and does not inherently damage hair if used correctly. Drying hair from the roots to the ends is generally a good practice; it helps to minimize stress on the hair and manage equipment effectiveness, as hair tends to style better when dried in a consistent direction. However, using high heat without protection remains the primary concern for hair health during the blowout process.