Don’t count on a beach umbrella to protect you fully from the sun’s ultraviolet (UV) rays—you still need to use sunscreen and take other sun-protective steps. In a study in JAMA Dermatology, researchers had 81 people spend 3½ hours at a sunny Texas beach in August. Half sat under a beach umbrella (6½ feet diameter) but used no sunscreen, while the other half used a high-SPF sunscreen and stayed out in the sun.
Nearly 80 percent of people in the umbrella-only group had some degree of sunburn the next day, compared to 25 percent of the sunscreen users. Even though the umbrella material allowed no UV to penetrate and participants were monitored to ensure that they got no direct sun exposure, the umbrellas couldn’t protect against indirect UV rays diffused by atmospheric particles or reflected off the sand.
This highlights “the importance of using combinations of sun protection practices to optimize protection against UV rays,” the study concluded. That also includes wearing a hat, covering up with clothing, and limiting exposure time.
Also see SPF: Is Higher Always Better?