Outdoor First Aid

The Specialist: Don't Get Sunburned

A lifeguard's guide to using sunscreen

Only fools get fried at the beach. But in the mountains, the sun can sneak up on you. UV rays intensify at altitude and reflect off snow and water, and intermittent tree coverage leads some hikers to put their guard down. That’s a mistake, says Jim Howe. He should know: as Honolulu’s Lifeguard and Ocean Safety Chief, Howe reviews medical studies on sunscreens, tests products (he’s tried 300), and sees firsthand how brutal burns can wreck a vacation. He offers these tips to help you enjoy your summer trip.

Choose SPF 30 Studies indicate that there isn’t any measurable benefit beyond 30. A higher SPF won’t hurt, but you should still reapply as you would a 30: every three hours. If you’re fair-skinned, sweating profusely, or hiking in the desert or above treeline, smear on a layer every 2 hours.

Read the ingredients The best sunscreens are made with moisturizing agents like cocoa butter, aloe, or lanolin. Alcohol-based products cause dryness, which can strip your skin of melanin, a natural pigment that protects against UV rays.

Select waterproofing carefully The active ingredient in waterproof sunscreens is supposed to sit on your skin: That’s what makes it work. But if the base ingredient remains on the skin too, the lotion wipes off easily. Avoid paraffin-based products and use an aloe or lanolin waterproof lotion like Native Tan 45, Howe’s favorite.

Make it a habit Forgetting to apply sunblock is the most common reason people get burned, says Howe. Apply yours when you get up so it becomes part of your routine.

Get full coverage Don’t ignore your ears, neck, and, if you hike in sandals or take off your boots at breaks, the tops of your feet. Slather up even if you’re just headed out for a 2-hour dayhike. Above treeline in summer, you can burn in as little as 30 minutes.