BECAUSE the health status of the candidates is an important issue for voters, U.S. News & World Report asked the private physicians of the major contenders for their complete medical reports. In general, the examinations show that the candidates are in good health for men of their ages. Jimmy Carter:

Born Oct. 1, 1924; height, 5 feet 9 1/2 inches; weight, 150 pounds. The White House physician, Dr. William Lukash, reports that the president "has maintained good health."

At Carter's most recent medical examination in July, all tests were normal His blood pressure was normal at 114 over 80, with a resting pulse of 50. He had a cholesterol level of 229, also within the normal range. No abnormalities were found in his heart or lungs.

Carter's chronic hemorrhoids have been inactive in recent months. His problem with skin keratoses -- irritating blemishes on his skin due to sun damages -- have responded well to treatments with a pencil-like device that freezes off the lesions.

To keep fit, Carter jogs between 3 and 4 miles a day. Since becoming president in 1976, he has lost about 10 pounds. He also does daily stretching exercises, swims five or six laps after jogging and plays tennis once or twice a week with his wife Rosalynn.

Every few weeks Carter goes trout fishing near Camp David, and in recent months he has taken up tying fishing flies for relaxation.

The president will drink a martini now and then but never drinks beer, because he is allergic to hops. He also is allergic to lima beans and Swiss cheese.

Carter reads three or four "light" books weekly and sees one or two movies on weekends. He sleeps only about six hours a night and is back at work in his office by 5:30 in the morning. "He has very positive health habits," says Dr. Lukash. Ronald Reagan:

Born Feb. 6, 1911; height, 6 feet 2 inches; weight, 194 pounds. The biggest concern about the Republican challenger is his age. If Reagan wins in November, he would be a month short of 70 at the time of his inauguration.

Doctors who have examined the GOP nominee insist, however, that there is no medical reason why he could not take on the duties of president and add that he actually appears physiologically younger than his chronological age.

Reagan has a statistical probability of living to the age of 80, reports the National Center for Health Statistics.

At his last physical examination in October 1979, by Los Angeles physician John Reynolds, Reagan's blood pressure was normal for a man his age at 130 over 80, with a resting pulse of 80.

On the treadmill stress test, he achieved 100 percent of the maximum heart rate predicted for his age. There was no evidence of heart disease.

In 1967, Reagan underwent a successful prostate operation. In 1979, he felt a numbness in a thumb, a symptom that doctors determined was caused by osteoarthritis, a degenerative disease of the joints.

Reagan suffers from chronic hay fever and since 1971 has been receiving desensitizing injections to control allergic symptoms. He also has a slight hearing loss in both ears but does not need a hearing aid.

To keep fit, Reagan rides horseback, chops wood and swims. He also uses a roller device for daily exercises to keep his stomach flat.

Reagan loves desserts, especially chocolate brownies, but watches what he eats to keep his weight down. When he quit smoking several years ago, he began eating jellybeans and still keeps a jar full of them on his desk. He drinks in moderation, with a preference for an occasional vodka and orange juice or a glass of wine. Reagan sleeps about eight hours a night, and his daily schedule usually starts at 10 a.m. John Anderson:

Born Feb. 15, 1922; height, 5 feet 10 1/2 inches; weight, 148 pounds. After a medical examination last January, congressional staff physician Lee Mandel reported jto Anderson: "I found you to be in excellent health. There is nothing to contraindicate your vigorous pursuit of office."

Anderson's blood pressure was normal, measured at 120 over 68, with a resting pulse of 58.

He has a common heart-valve condition known as systolic-click-murmur syndrome but experiences no dizziness or chest pains. He takes no medication but is advised to take antibiotics before any dental procedures, which often involve bleeding in the mouth, to prevent bacteria from entering the blood stream and possibly causing infection in his heart.

Anderson also has varicose veins but does not experience any pain or swelling in his lower extremities and is able to stand for long periods.

The independent candidate has had two fractures: the left forearm in 1969 and the right lower leg in 1972. He dislocated his right shoulder in 1977. In 1975, a biopsy of the right breast was negative.

Anderson's major form of exercise is swimming an hour a day. He also likes to go fishing with his family, and he took up skiing in 1970.

In March 1979, Anderson quit smoking after being an intermittent pack-a-day smoker for 30 years. He limits his drinking to 2 ounces of alcohol a day, with a preference for beer or hard liquor. He does not care for wine. He sleeps 7 hours a night, reads history for relaxation.