AEROBICS--The most beneficial forms of exercise are aerobic exercises. Some activities to consider:

• Walking--Walk briskly, arms swinging vigorously. Walking is inexpensive and requires no special equipment (except for a pair of comfortable shoes).
  
• Jogging/running--Wear properly fitted shoes designed for running; whenever possible, run on resilient surfaces such as blacktop or turf, rather than concrete.
  
• Bicycling--Wear a helmet and follow the rules of the road.
  
• Aerobic dancing--Lively music encourages vigorous group participation, but each person should work in his or her own target heart range. Low-impact aerobics is a particularly good way for beginners and overweight people to start. In fact, many people continue to do only low-impact exercises because they find them more comfortable and because the possibility of injury is reduced.
  
• Swimming--Swimming is easy on body joints. Variety comes from using different strokes.
  
• Cross-country skiing--An almost total workout for the major limbs of the body, the activity tightens the torso muscles, helps promote lung capacity, and provides excellent aerobic conditioning.
  
• Fitness equipment--Most aerobic activities can be done indoors on exercise equipment at home.

WHEN TO EXERCISE--The hour just before the evening meal is a popular time for exercise. The late afternoon workout provides a welcome change of pace at the end of the day and helps dissolve the day's worries and tensions. Another popular time of day to work out is early morning, before the day's main activities begin. Advocates of the early start say it makes them more alert and energetic during the day. Beware--morning stiffness is universal in seniors and can increase the likelihood of injury. If you exercise in the morning, wait a half hour after getting out of bed and, in addition, spend more time in warm-up activity.

Among the factors you should consider in developing your workout schedule are personal preferences, your plans for the day, availability of exercise facilities, and weather.

You should not exercise strenuously during extremely hot, humid weather or within two hours after eating. Heat and/or digestion both make heavy demands on the circulatory system, and in combination with exercise can be an overtaxing double load.

CLOTHING--All exercise clothing should be loose-fitting to permit freedom of movement, and should make you feel comfortable and self-assured. As a general rule, you should wear lighter clothes than temperatures might indicate. Exercise generates great amounts of body heat. Light-colored clothing that reflects the sun's rays is cooler in the summer, and dark clothes are warmer in the winter. When the weather is very cold, it's better to wear several layers of light clothing than one or two heavy layers. The extra layers help trap heat, and it's easier to shed one of them if you become too warm.

In cold weather, and in hot, sunny weather, it's a good idea to wear something on your head. Wool ski caps are recommended for winter wear, and some form of tennis or summer hat that provides shade and can be soaked in water is good for summer. Never wear rubberized or plastic clothing. Such garments interfere with the evaporation of perspiration and can cause body temperature to rise to dangerous levels.