Sun exposure and heat stroke

All travelers should protect themselves from excessive sun exposure. Adverse effects include sunburn, sunstroke, damage to the eyes, and skin cancer. Those at greatest risk include babies and children, fair-skinned individuals, tanning enthusiasts, sportsmen, and outdoor workers. Especially in the tropics, travelers should stay out of the midday sun, wear sunglasses and a wide-brimmed sun hat, and apply sunscreen with SPF 15 or higher, with both ultraviolet A (UVA; wavelength 315-400 nm) and ultraviolet B (UVB; wavelength 280-315 nm) protection. Sunscreen should be generously applied to all exposed parts of the body approximately 30 minutes before sun exposure and should be reapplied after swimming or vigorous activity. Surfaces such as water, snow, and sand may reflect ultraviolet light and increase its effect.

Heat stroke may occur in those who are exposed to excessively high temperatures for a number of days. The elderly are at greatest risk, especially those with chronic medical problems. Heat stroke often occurs during physical exertion but, particularly in the elderly, may also occur at rest. The first sign may be an abrupt collapse, but there may be early, subtle findings, including dizziness, weakness, nausea, headache, confusion, drowsiness, and unreasonable behavior. If early symptoms of heat illness are observed, remove the victim from direct sunlight, loosen clothing, give cold fluids, and make sure the victim rests for at least 24 hours. In the event of heat stroke, the victim should be brought immediately to the nearest medical facility. To prevent heat stroke, drink plenty of fluids, eat salty foods, protect yourself from sun exposure, and avoid alcohol and strenuous exercise when the temperature is high.

From the Centers for Disease Control

Sunscreen: How To Select, Apply, and Use It Correctly

From "International Travel and Health" (WHO)

Environmental health risks

From the National Travel Health Network and Centre (U.K.)

Sun Protection

From "Health Information for Overseas Travel" (U.K.)

Environmental hazards: heat, cold and altitude