Water can dramatically change the way our hair looks and acts. The structure of wet hair feels and acts different than dry hair. When wet, hair appears to be longer, heavier and smoother. But what are the actual physical changes between wet and dry hair?
Hair is permeable, meaning it allows water to pass through it. This permeability allows hair to absorb large amounts of water. Healthy hair can absorb over 30 percent of its weight in water. Damaged hair can hold even more, allowing for up to 45 percent of its weight in water. This water absorption leads to swelling in the hair shaft. When wet, hair’s diament can swell 15 to 20 percent. The heaviness of wet hair is a result of the water absorbed by the hair.
Wet hair also allows for greater elasticity. When healthy hair is wet, it can stretch in length by up to 30 percent, while still being able to return to its original length after drying. This increase in elasticity is why your hair appears longer when wet. However, stretching your hair too much when wet can lead to damage and possibly breakage. When hair is stretched over 30 percent of its original length, permanent damage begins to occur. Hair stretched 80 percent of its length will fracture.
Due to its greater elasticity, wet hair is more sensitive than dry hair. Wet hair has a higher combing friction than dry hair, making it more susceptible to damage. Combing wet hair is more likely to stretch already brittle hair beyond its breaking point.
Different types of water have different effects on hair and hair structure. Prolonged exposure to saltwater can dry out hair, leaving your hair brittle and rough. Saltwater damage can cause the ends of hair to split and break. Water with chlorine can strip hair of its natural lubricant, leaving hair dry and porous. Hard water can also affect hair structure. Hard water contains a large amount of minerals, such as calcium and magnesium, which can build up on the hair and scalp. Prolonged use of hard water can leave hair feeling dry, brittle and weighed down.
When hair is wet, its structure and feel change. Water causes hair to be heavier, more elastic and more sensitive. Due to the increased sensitivity of wet hair, it is important to be gentle with your wet hair. Wet hair is at a greater risk for damage and breakage.