Weather / Environmental elements
Cold winds and low temperatures can dry out skin, depriving it of balanced levels of oils, and contributing to premature aging.
Prolonged exposure to the sun causes water to evaporate from skin.
Forced air heating also dries out skin: warm, dry air acts like a
sponge, soaking up moisture from everything it touches.
Lifestyle
The trend of low-fat or fat-free diets can deprive our bodies of
skin-friendly Essential Fatty Acids (EFAs) critical to all parts of a
healthy functioning body. They help protect against water loss within
cells and throughout skin, helping to prevent dryness, keeping skin
supple and hydrated. An EFA deficiency can result in chronic itching,
dryness, scaling, and thinning.
Smoking can have a drying effect on skin: it drains skin and body of
vitamins A and C and constricts blood vessels (which equates to less
blood flow) – meaning smoking is somewhat like suffocating skin from the
inside.
Excess intake of alcoholic beverages and certain medications (such as nasal decongestants) can also contribute to dry skin.
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Dermalogica