Hawaii is known not only as the Aloha State, but also as the Health State. The life expectancy here is 82.4 years, the longest in the nation. Balmy weather makes it easy to remain active year-round, and the low-stress attitude seems to contribute to the general well-being. When visiting the Islands, however, there are a few health issues to keep in mind.
The Hawaii State Department of Health recommends that you drink 16 ounces of water per hour to avoid dehydration when hiking or spending time in the sun. Use sunblock, wear UV–reflective sunglasses, and protect your head with a visor or hat. If you're not acclimated to warm, humid weather, you should allow plenty of time for rest stops and refreshments. When visiting freshwater streams, be aware of the tropical disease leptospirosis, spread by animal urine and carried into streams and mud. Symptoms include fever, headache, nausea, and red eyes. If left untreated it can cause liver and kidney damage, respiratory failure, internal bleeding, and even death. To avoid this, don't swim or wade in freshwater streams or ponds if you have open sores and don't drink from any freshwater streams or ponds.
On the Islands, fog is a rare occurrence, but there can often be "vog," an airborne haze of gases released from volcanic vents on the Big Island. During certain weather conditions, such as "Kona Winds," the vog can settle over the Islands and wreak havoc with respiratory and other health conditions, especially asthma or emphysema. If susceptible, stay indoors and get emergency assistance if needed.
The Islands have their share of insects. Most are harmless but annoying, but Dengue fever, a mosquito-borne disease, has been reported in Oahu. When planning to spend time outdoors in hiking areas, wear long-sleeve clothing and pants, and use mosquito repellent containing DEET. In damp places you may encounter the dreaded local centipedes, which are brown and blue and measure up to eight inches long. Their painful sting is similar to those of bees and wasps. When camping, shake out your sleeping bag and check your shoes, as the centipedes like cozy places. When hiking in remote areas, always carry a first-aid kit.