IMPORTANCE Sun-protective behavior affects skin cancer prevention. Shade works by physically shielding skin from direct harmful UV rays; however, skin may still remain exposed to reflected and indirect UV rays. There is no current standard metric to evaluate shade for its effectiveness in sun protection, and there is insufficient clinical evidence that a beach umbrella alone can provide adequate sun protection.OBJECTIVE To directly measure sunburn protection offered by a standard beach umbrella compared with that provided by sunscreen with a high sun protection factor under actual use conditions. DESIGN, SETTING, AND PARTICIPANTSA single-center, evaluator-blinded, randomized clinical study was conducted from August 13 to 15, 2014, in Lake Lewisville, Texas (elevation, 159 m above sea level), among 81 participants with Fitzpatrick skin types I (n = 1), II (n = 42), and III (n = 38). Participants were randomly assigned to 2 groups: 1 using only a beach umbrella, and the other using only sunscreen with a sun protection factor of 100. All participants remained at a sunny beach for 3½ hours at midday. Clinical sunburn evaluation of each individual for all exposed body sites was conducted 22 to 24 hours after sun exposure. INTERVENTIONSThe shade provided by a beach umbrella or protection provided by sunscreen with a sun protection factor of 100. MAIN OUTCOMES AND MEASURESSunburn on all exposed body sites 22 to 24 hours after sun exposure.RESULTS Among the 81 participants (25 male and 56 female; mean [SD] age, 41 [16] years) for all body sites evaluated (face, back of neck, upper chest, arms, and legs), the umbrella group showed a statistically significant increase in clinical sunburn scores compared with baseline and had higher postexposure global scores than the sunscreen group (0.75 vs 0.05; P < .001). There was a total of 142 sunburn incidences in the umbrella group vs 17 in the sunscreen group. Thirty-two of the 41 participants (78%) in the umbrella group showed erythema in 1 or more sites vs 10 of the 40 participants (25%) in the sunscreen group (P < .001). Neither umbrella nor sunscreen alone completely prevented sunburn. CONCLUSIONS AND RELEVANCEA beach umbrella alone may not provide sufficient protection for extended UV exposure. It is important to educate the public that combining multiple sun protection measures may be needed to achieve optimal protection.

OBJECTIVE: Sweating plays a critical role in maintaining thermal balance and keeping skin cool during exercise. People often wear sunscreens on hot summer days for sun protection. Most recreational sunscreens are designed to be water-and sweat-resistant, so that sweating will not remove or compromise the protection. The objective of this study was to determine whether wearing sweat-resistant sunscreen might impede natural sweating, potentially interfering with thermal regulation and resulting in the elevation of skin temperature. METHODS: We conducted a controlled, randomized, split-face and split-arm clinical study with 24 female subjects wearing an SPF 70 lotion sunscreen on half of the face and an SPF 70 spray sunscreen on one of the forearms at a dosage of 2 mg cm À2. Following sunscreen application, subjects participated in two sessions of indoor exercise to induce clearly visible sweating. RESULTS: We found that both skin temperatures and sweat evaporation rates were significantly elevated after each session, yet there were no significant differences in either skin temperatures or sweat rates between the treated and untreated control sites at any time point for any of the skin sites measured. CONCLUSION: We conclude that the application of tested sweatresistant sunscreen lotions and sprays does not have any measurable effects on skin cooling by natural sweating process. People should continue to use these sunscreens during recreational activities.R esum e OBJECTIF: La transpiration joue un rôle essentiel dans le maintien de l' equilibre thermique et pour garder la peau fraiche pendant l'exercice. Les gens portent souvent des ecrans solaires pendant les chaudes journ ees d' et e pour se prot eger du soleil. La plupart des ecrans solaires r ecr eatifs sont conc ßus pour r esister a l'eau et a la transpiration, de sorte que la transpiration n' elimine ni ne compromet la protection. L'objectif de cette etude etait de d eterminer si le port d'un ecran solaire r esistant a la transpiration pourrait entraver la transpiration naturelle, interf erant potentiellement avec la r egulation thermique et entraînant une el evation de la temp erature cutan ee. M ETHODES:Nous avons men e une etude clinique contrôl ee, randomis ee, h emi-visage et bras droit -bras gauche, avec 24 sujets f eminins portant un lotion solaire SPF 70 sur la moiti e du visage et un ecran solaire SPF 70 sur un des avant-bras a un dosage de 2 mg/cm2. Apr es l'application de la cr eme solaire, les sujets ont particip e a deux s eances d'exercices en salle pour induire une transpiration clairement visible. R ESULTATS: Nous avons constat e que les temp eratures cutan ees et les taux d' evaporation de la sueur etaient significativement elev es apr es chaque s eance, mais qu'il n'y avait pas de diff erences significatives de la temp erature cutan ee ou de la sudation entre les sites trait es et non trait es. CONCLUSION: Nous concluons que l'application de lotions antisolaires r esistants a la transpiration test es et des sprays n'a aucun effet m...

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