Summertime, and -- without being too bleak about it -- the living's not necessarily easy. That is, if you consider all the emergencies that can arise in the pursuit of play.

Courses in first aid -- the aid first given to a victim of illness or accident before professional help arrives are available for children from fourth grade up, as well as for adults.

The American Red Cross, which has become virtually synonymous with first aid and safety instructions, offers a wide range of courses. While no longer free, they are inexpensive, with fees covering only the cost of materials; instructors are volunteers.

All branches offer first-aid courses at various levels, and both the Red Cross and the American Heart Association offer separate classes in cardiopulmonary resuscitation (CPR), a skill designed to save a life -- with the sole equipment of breath and hands -- at the moment of cardiac arrest. Most branches of the Red Cross also swimming and lifesaving instruction, and many offer courses in small-craft (boating) safety.

Some chapters will bring the first-aid course to you for groups of six or more.

A sampling of courses offered in the area:

Standard First Aid -- Prepares people to care for injuries and handle emergencies while professional medical assistance is on the way. Two packages: traditional 21-hour course offered in 3-hour doses, and the more popular 8-hour "multimedia" course which can be taken in one, 8-hour session or two, 4-hour sessions.

The 21-hour course ($8 per person) is taught with lectures, discussion, demonstrations and practice sessions. The 8-hour course ($8) makes use of filmed demonstrations, practice sessions and a programmed workbook. It is a condensed version of a 21-hour course designed by educationalists at the Bell Telephone System to meet training standards under the Occupational Safety and Health Act. You must be at least 13, or have graduated from the seventh grade, to take either course.

Advanced First Aid -- Designed for people responsible for giving emergency care to the sick and injured. For ages 15 and up, approximately 33 hours, $8. Covers basic material, plus more advanced skills such as auto extrication.

Basic First Aid -- To acquaint school children, fourth grade and up, with basic safety and first-aid measures, 9 hours, $5.25.

Cardiopulmonary Resuscitation (CPR) -- Techniques include mouth-to-mouth resuscitation plus external compression of the heart to restore breathing and heartbeat in victims of cardiac arrest (heart attack), and removal of foreign bodies in the airways of adults, children and infants.

Classes taught by both the Red Cross and the American Heart Association, 337-6400.

There are chapters of the American Red Cross in most county seats. If you have trouble locating one near you, call the district office for information (857-3642); in areas north and east of Northern Virginia, the Baltimore office, (301) 467-9905. Ask for Safety Services.

Among basic Red Cross handbooks you might have on hand:

Standard First Aid and Personal Safety (Doubleday, 269 pages, $2.50); Advanced First Aid and Emergency Care (Doubleday, 318 pages, $3); Basic First Aid, a set of four workbooks for children (Doubleday, $5.50 for the set).

Other resources:

* The American Outdoor Safety League's bright orange pocket-sized first-aid guide, Emergency/Survival Handbook ($2.95), the centerfold of which is a bright piece of foil that can be used as a distress signal to aircraft or search parties. Available at some outdoors outfitters, or by sending a check for $2.95 to The Mountaineers, 719 Pike St., Seattle, Wash. 98101.

* The Washington Hospital Center's handy Emergency First-Aid Chart that gives one-paragraph instructions about what to do for bites and stings, bleeding, burns, choking, electric shock, fractures and other emergencies and explains briefly how to administer rescue breathing. For a free copy, write to the Public Affairs Department, Washington Hospital Center, 110 Irving St. NW, Washington, D.C. 20010, and enclose a 20-cent stamp.

For groups of 25 or more, emergency-room nurses from the hospital will present a 15-minute slide show on "What to Do Until the Ambulance Comes," followed by a question-and-answer period.