Situation: A 58-year-old man who has fished for a living since age 15 comes to the clinic because of a dark, irregular patch on the sole of his left foot. The nurse teaches sun protection to him and his co-workers. Which statement shows correct understanding?

Broad-spectrum sunscreen of sun protection factor 30 or higher is applied before going out and reapplied every 2 hours and after swimming or sweating, whatever its factor or water resistance. Shade reduces but does not remove exposure, because water and sand reflect ultraviolet rays.

Clinical context and priority nursing focus
A 58-year-old man with decades of occupational sun exposure presents with a suspicious pigmented lesion on the sole of the foot. While the lesion itself requires referral and diagnostic follow-up, the teaching point in this item is primary prevention for him and his co-workers. The nurse must correct common misconceptions about sunscreen use, because outdoor workers such as fishers accumulate high lifetime ultraviolet radiation exposure and face an increased risk of actinic keratoses and skin cancer ^[2]. The correct response is the one that reflects the American Academy of Dermatology recommendation for reapplication.

Why option 1 is correct
Broad-spectrum sunscreen with a sun protection factor of 30 or higher should be applied before going outdoors and reapplied every 2 hours and after swimming or sweating ^[1][3][4]. The statement “I will reapply sunscreen every 2 hours and after I get wet” matches this guideline exactly. Reapplication is required regardless of the SPF number or whether the product is labeled water-resistant, because sunscreen is removed by water, friction, and perspiration, and its protective film degrades over time ^[1][3]. For outdoor workers, adherence is often low, so reinforcing the reapplication schedule is a high-yield nursing intervention ^[2].

Why the other options are incorrect

Option	Misconception	Correct understanding
2. Under the boat’s canopy at noon, I can skip sunscreen.	Shade eliminates ultraviolet exposure.	Shade reduces but does not remove exposure; water and sand reflect ultraviolet rays, so reflected radiation still reaches the skin [1][4].
3. A factor 50 sunscreen put on once in the morning lasts all day.	Higher SPF extends duration of protection.	SPF indicates the degree of protection against UVB, not the duration; reapplication every 2 hours is still required [1][3][4].
4. Water-resistant sunscreen does not need reapplying after a swim.	Water-resistant means waterproof or permanent.	Water-resistant products still lose effectiveness with water exposure and toweling; reapply after swimming or heavy sweating [1][3].

Pathophysiology and occupational risk
Solar ultraviolet radiation is a major environmental carcinogen. Chronic exposure causes DNA damage in keratinocytes and melanocytes, leading to actinic keratoses and skin cancers, including melanoma ^[2]. Fishermen and other outdoor workers begin exposure early in life and continue daily, so their cumulative dose is far higher than that of recreational sun exposure. This makes consistent sunscreen use and reapplication a critical occupational health behavior, not a cosmetic choice ^[2]. The lesion on the sole is also a reminder that melanoma can occur in sun-protected sites, especially acral lentiginous melanoma, so teaching sun protection does not replace the need for biopsy or referral.

Key point! Sunscreen reapplication every 2 hours and after water exposure or sweating applies to all sunscreens, including high-SPF and water-resistant products ^[1][3][4].
Watch out! Shade under a canopy or umbrella does not block reflected UV rays from water, sand, or boat surfaces ^[1][4].