Strength training is recommended for everyone, two to three times per week.
Beginners should start with light weights or low settings on weight machines. One set of 5 to 15 repetitions of each exercise can improve muscle strength and endurance nearly as much as the traditional three sets, at least for beginners.

Stretching should be done for 10 to 20 minutes at least two to three times per week.

Benefits of Exercise

Stay Young
A sedentary lifestyle accelerates nearly every unwanted aspect of aging.  On the other hand, physical activity slows the decline of muscle strength, maintains better cardiovascular and respiratory function, limits the risk of developing diabetes, and increases bone mass, which helps prevent osteoporosis.

Exercise also aids in digestion, promotes efficient bowl function, reduces insomnia, and prevents depression.

To be effective, your exercise routine should include the two major components of fitness--- endurance training and strength training.

Types of Exercise

Endurance Training
Endurance training is frequently referred to as cardiovascular or aerobic exercise because it increases the demand placed on the cardiovascular and respiratory systems. The most popular are walking, jogging, and cycling. However, any total body activity that increases your heart rate would be considered to be endurance training.

Strength Training
This is highly individualized and is somewhat of a trial-and-error process in the beginning. Use light weights (between 1 and 12 pounds) to work the major muscle groups. You should be able to complete 10 to 12 repetitions of three sets each. If you cannot do 12 repetitions, the weight is too heavy. Two to three strength training sessions a week are ideal.

Estimating Daily Caloric Needs

National Research Council
A rough estimate is offered by the National Research Council for estimating your caloric needs based on age and activity level. The chart below is for individuals 19 to 50 years of age. For those over age 50, the numbers are 15 to 20% lower.

National Research Council
The chart below is for individuals over 50 years of age. As people age, their metabolism slows. So, their energy needs drop by approximately 15 to 20%. The table below gives you the average of this and shows calories needed at 17.5% less than individuals in the 19 to 50 year old age range.

•    Sedentary means seated and standing activities, such as driving or typing.
  
•    Light refers to activities such as leisurely walking, house cleaning, and golf.
  
•    Moderate includes brisk walking, cycling, tennis, dancing, and weeding.
  
•    Heavy means running, basketball, soccer, and heavy manual labor.