Good health at Pennsic can best be assured by good sense! The War Chirurgeon has published an extensive list of things to do, and not do, but in general:

Be sensible about climate and weather. During the hot part of the day, stay out of the sun as much as possible. SPF-99 sunscreen is not as good at protecting you as a good-sized tree or a dining fly. Wear a hat when you go out! During the evening, especially if it is rainy, you can lose a lot of body heat. Hypothermia is one of the most common illnesses treated by the Chirurgeons. Wear warm clothing and good footgear, and avoid excessive consumption of alcohol. If you do feel numbness or other hypothermia symptoms, get out of the cold and see a Chirurgeon before the problem gets worse.

Hydrate, hydrate, and then hydrate some more! Drink as much water during the day as you can. Your body needs it to get rid of heat and to flush out toxins that occur naturally in your blood. Alcohol does not count, and can actually make matters worse. Gatorade™ (and similar products) are hypotonic, which means that their concentration of sugar and salt is high enough to actually remove water from the blood into the stomach and intestines. Drink plain water, or Gatorade cut fifty-fifty with plain water. If you plan on fighting or doing other heavy physical activity, start hydrating yourself at least an hour before the physical activity begins, then continue throughout.

It sounds unpleasant, but a good way to monitor your hydration level is to pay attention to your frequency and volume of urination. If you are not urinating regularly, or are urinating only small quantities, then you are not drinking enough water.

Practice good camp sanitation and personal hygiene. Those flies flitting about your uncovered dinner leftovers may have just been flitting about the porta-castle a moment ago. Doesn't that make you want to do your dishes promptly? Use a mixture of 100 parts water and 1 part chlorine bleach to sanitize your dishes, cookware, and eating table after every meal. Your personal cleanliness is more than just courtesy to campmates: in hot August weather, some truly unpleasant skin rashes can result from not showering often enough. Also, make sure that you wear shoes when using the port-johns. Enough said!

Follow camp safety rules and use common sense. It is with good reason that the Fire Marshall forbids open flames in tents. A canvas or nylon tent burns fast, burns hot, and has only one exit! If your tent catches fire, you will certainly lose most or all of your gear and may be badly injured or killed. A tent can burn to cinders in seconds under the right conditions, and one tent fire may spread to nearby tents with surprising speed. Keep flames away from tents, do not leave fires unattended, and keep the required number of fire buckets and extinguishers within easy reach. The first year the authors of this document camped together at Pennsic, a defective tiki torch broke open and spilled burning fuel on the ground five feet from the tent. Fortunately, a fire extinguisher was at hand and what could have been a tragedy was only a frightening incident and the cost of a new torch. Be careful with sharp objects, and follow standard SCA safety practices with live steel weaponry.

Don't be a hero(ine)! At Chirurgeon's Point, the expression "testosterone poisoning" is used for the idiots (male or female) who lack the good sense to know when enough is too much. You are not helping your fighting comrades if you go into battle when you are sick or have a sprained ankle, and you may wind up missing the rest of the war because you hurt yourself so badly that you are hospitalized. "Carrying on nobly" in battle in spite of heat exhaustion is equally stupid, and if your brain is messed up with the heat you could end up being hurt badly or hurting someone else. In any case, you won't be much help to your colleagues in that condition, so take a break until you feel better. For minor wounds, see a Chirurgeon to get the wound properly cleaned and prevent an infection that could end your War prematurely. Finally, in emergency situations such as fires or accidents, your first duty is to send someone for help. Once that is done, then and only then should you respond to the emergency according to your level of training and the available resources.