In an article published in TIME, experts detailed the detrimental effects of wearing makeup during exercise. Skin and pores play a critical role in evaporation, sweating, debris removal, and temperature regulation—especially during exercise, when the body’s heart rate and metabolism increase. When pores are blocked, these functions may be impaired. In a recent study published by Yoon et al in the Journal of Cosmetic Dermatology, researchers applied a generic cream foundation to the foreheads and undereye areas of 43 individuals. They then asked the participants to run on a treadmill for 20 minutes and then used a device to measure their skin’s moisture levels, oil amounts, and pore sizes. The researchers found that compared to the portions of the participants’ faces without makeup, the portions with makeup demonstrated higher levels of moisture, smaller pores, and greater sebum levels. These findings indicated that skin covered in makeup may exhibit poor evaporation, moisture regulation, oil and debris removal, and oil regulation; higher dirt and bacteria buildup; and a greater risk of acne. The researchers plan to extend their study to include other types of foundations and sunscreen to better understand how these products impact the skin during exercise.