They say to limit exposure to the sun when on MTX. I started MTX in late January, been cutting grass (2 1/2 hr job, riding mower) since April in shorts and short sleeve shirt. No problems, normal farmers tan. We decided to slip down to Panama City Beach this weekend. I remembered the warning so on Saturday stayed under the umbrella except for very brief excursions into the water to cool. Yes, sunscreen in use. Sunday, arms legs fine, upper back/shoulders very slight discomfort, chest and stomach like a lobster. The reflection of the sun off the Gulf onto the previously unexposed skin got me! Lesson learned, suggest y'all not repeat my mistake.