VOTERS WILL GO to the polls Tuesday with insufficient information on the health status of the candidates. What medical data has been released is incomplete and raises unanswered questions. Ronald Reagan, the oldest incumbent president in our nation's history, has dismissed the age issue with a joke. Walter F. Mondale's physician is no longer granting interviews to the press. Such cavalier attitudes ought not be taken lightly by the electorate.

History offers many examples of political leaders' serious illnesses that were deliberately hidden from the public.

After Winston Churchill died, his physician, Lord Moran, released details of Churchill's health and personal habits while he was prime minister that were shocking in retrospect.

Presidents Cleveland and Wilson suffered serious illnesses while in the White House, but the public was not fully informed about them.

Franklin Roosevelt developed progressive health problems during his presidency far more serious than the paralysis that antedated his election.

John Kennedy's Addison's disease was described publicly only as a "mild adrenal insufficiency."

In an era of black boxes and red telephones, the availability and alertness of the president should be of paramount interest to all the voters. The candidates' health status should be as well known to the electorate as their postition on school prayer or nuclear disarmament.

Reagan is said to be in excellent health except for decreased hearing and unspecified allergies for which he takes shots. The released measurements of weight, blood pressure and cholesterol and the results of an electrocardiogram are clearly within acceptable limits. But Reagan appeared to tire at the end of the first 90-minute debate. He seemed to lose command of his material. He also wandered badly in the telling of two anecdotes, failing to make his point in the alloted time at the end of the second debate.

Stamina and powers of concentration are not usually measured during routine physical examinations. Instead, personal observation of an individual's performance over a period of time is often taken as indirect evidence that all is well. Repeated testing of reasoning by verbal IQ tests and of motor functions, for example by analysis of handwriting samples, would be more meaningful than a statement released through the White House that typically uses inexact phrases such as " . . . mentally alert . . . robust . . . appears younger than his stated age." These are the hackneyed phrases in the report of a physical examination worthy of a third-year medical student, not an assessor of presidential health.

Testing specific functions over time is more useful to detect change. No serious conclusions can be drawn from incomplete medical data and expert opinions rendered by spokesmen whose objectivety is open to question.

The voters can only be slightly more satisfied with what is known about Mondale's health. The same sorts of medical test results and measurements have been released by his personal physician of 20 years. We know that Mondale has moderately high blood pressure controlled by three medications and takes a potassium supplement required to correct a common side effect of his antihypertensive medications. He has mild enlargement of the prostate gland and suffers from a "tennis elbow." His physician described him as "bouncy" and said, "He looks great" in a published interview. Not all would agree with that last statement. The press has duly reported the controversies over the candidate's recent debate appearance.

Requests for an interview with Mondale's physician, Milton Hurwitz, in connection with this article were refused by Mondale's staff. The most current detailed information supplied by his physician was released in November, 1983.

It is somewhat comforting to note that the observations and tests of Mondale's health status have been made by the same physician over a 20-year period. Health data was also released by Mondale during his successful 1976 campaign for vice president. At that time his blood pressure was controlled by two medications. His untreated blood pressure of 150/102 was clearly abnormal but was reduced to 134/84 by medication and compares favorably to the 138/80 readings recently published.

The addition of a third antihypertensive medication during the ensuing eight years is not unusual but does add the potential for increased side effects. One of the common side effects noted by his physician is a kind of depression. Mondale's style and delivery are known to be flat or subdued on occasion. His physician withdrew the antihypertensive drugs to see if they were affecting the candidate's campaign performances. Because Mondale's blood pressure began to rise, the medications were restarted. The other medical measurements released by Democratic sources are open to the same criticisms as Reagan's.

Although it is comforting on the one hand to have 20 years of continuous observations by one physician in Mondale's behalf, it must also be noted that a friendly physician may not be an objective observer. Rep. William Fitts Ryan of New York was locked in a close and bitter Democratic primary campaign with Rep. Bella Abzug in 1972. Questions were raised concerning his health status. During the campaign four physicians who personally knew and had worked with Ryan but apparently had not examined him attested to his "undiminished vigor" in a letter to The New York Times. Shortly after his primary victory, Ryan died of advanced cancer. It is reprehensible that four friendly physicians provided expert opinions on such flimsy evidence.

Illness in leaders can affect their function. At the height of his official responsibilities, Churchill could not concentrate very long on one topic and required briefing memos limited to one short paragraph. Woodrow Wilson, our 28th president, had a long and puzzling history of neurologic complaints and findings that predated his election. They continued to develop in his first term. That he was incapacitated by a stroke during his stressful campaign to gain ratification of the League of Nations should surprise no one. He finished his second term, a shell of his former self while his executive functions were largely performed by his wife and secretary, neither of whom was elected to do so.

That serious health problems have been hidden from the electorate is a matter of historical record. The existence and severity of John F. Kennedy's Addison's disease was not acknowledged during his presidential campaign and yet his case was of such interest to the scientific community that it was reported in the medical literature as an example of a severe disorder. In Addison's disease the adrenal gland is unable to produce various steroid hormones that act as controllers of a wide variety of the body's physiologic systems. Mental alertness and stamina are among the functions that can be influenced adversely by shifts in the availability of adrenal hormones. President Kennedy was on large doses of steroid replacement therapy. His decision-making in the Cuban missile crsis has been lauded but during the Bay of Pigs it has been questioned. It is conceivable that his good and bad days were medically related. The voters elected Kennedy on the basis of incomplete data.

Even if a physician makes a complete and candid assessment of a candidate's health, nothing guarantees that the candidate or his or her staff will accurately and completely communicate the findings.

Early in the 1976 Democratic primaries, there were 11 candidates including Sen. Birch Bayh of Indiana. Brief health sketches on each were published in national magazines. Bayh's spokesman reported that he had multiple lung abnormalities attributed to the same condition, a benign inactive fungal infection. The implication was that the abnormalities were identical.

In fact, all the lung abnormalities were not alike. After Bayh withdrew from the race he entered Georgetown University Hospital for the removal and further study of one of the nodules. If that nodule had been identical to the others there would have been no grounds for excision. That it, too, was benign was a happy outcome. That the physician's just concerns were not fully reported by the candidate's staff is an example of the complexity of any attempt to provide the electorate with meaningful, useful and complete health data on seekers of high office.

Former President Gerald Ford has done much to establish precedents in the manner by which medical data can be made available. Because Ford was appointed to the office of vice president under President Richard Nixon and in fact became president without ever having gone through a presidential campaign, he voluntarily released to congressional committees much of his past medical history and test results. In 1975, Ford authorized the attending physican of the Congress to make available to the House Judiciary Committee all of the medical records in the physician's possession.

If the electorate is to have adequate medical information as one basis for decision-making in presidential elections, we need to have a medical history and the results of thorough physical examinations conducted over a period of years by competent, independent medical personnel. Tests of body fluids that reflect the function of vital organs such as the brain, lung, heart, liver and kidneys should be included. Physiologic tests should be measured at rest and with activity as appropriate. The disclosure should include a listing of th candidates' hospitalizations and surgical procedures in the past 10 years, the number, reasons for and outcomes of consultations with medical practitioners in the last five years, a list of medications and dosage levels used in the last two years and statements regarding personal health habits such as the use of alcohol, tobacco, diet and exercise levels.

Such an examination should be undertaken and released voluntarily, documented and certified by accepted laboratories outside the direct control of the candidate. If there is to be debate on the interpretations of the findings, so be it. Campaigns are based on advocacy and adversial confrontation. No physician should attempt to interpose himself to block a candidate from running for medical reasons.

Expanded medical data of the type noted above should be added to the list of variables voters now use in the election process. The potential of a Franklin Delano Roosevelt should not be restrained from running for president simply because of partial paralsis. But by the end of his third term Roosevelt was a very sick man. He had sustained high blood pressure at a time when available treatment of hypertension was inadequate. Lingering doubts about the true cause of Roosevelt's death persist. It has been speculated that a malignant melanoma ("black mole" disease) had spread to his brain. Photographs taken before 1943 clearly show a large pigmented mole over his left eyebrow that is absent in later pictures. It is likely that it was surgically removed.

In the future we may not be as fortunate as the nation was when President Grover Cleveland secretly underwent removal of a portion of his lower jaw on a yacht anchored off Manhattan. That he was able to address a special session of the Congress three weeks later during debate over a domestic money crisis was not so much a tribute to his recuperative powers and the expertise of his surgeons as it was an expression of the slow pace at which even crises moved in the late 19th century.

It was once believed that the rigors of campaigning served as a test of the candidate's stamina and staying power. We have lost that advantage. Modern communications technology and techniques have changed the campaign trail enormously. Now media consultants blanket the airwaves with repeated cameo spots of their candidate. Ironically enough, high tech communications are a two-edged sword -- protecting seekers of high office from close scrutiny while running but also increasing the stress on them once elected by putting them constantly on call.

In today's era of instant replay and rapid communications systems, the presidency should be filled by one who is likely to be alert and available at all times. Our confidence that we are electing such a candidate is less than it should be.