There is no clear relationship between a president’s performance and his well-being. For instance, Dwight D. Eisenhower had a series of medical issues while in office, including a heart attack, a bowel obstruction and a stroke. But historians have written approvingly of his presidency and his ability to achieve consensus. In a 2015 ranking of the presidents from a survey of political scientists, he came in seventh. Perhaps one of the sickest presidents in the country’s history was John F. Kennedy, who suffered not only from a failure of the adrenal glands, known as Addison’s disease, but also from debilitating back pain. A physician, Janet Travell, treated Kennedy with narcotics, stimulants and various hormones. Most worrisome, Kennedy retained the services of a shady physician named Max Jacobson, who injected him with amphetamines. Yet while some of Kennedy’s decisions, such as the ill-fated Bay of Pigs invasion, involved poor judgment, Kennedy biographer Robert Dallek found no definitive evidence that the illnesses or medications were the cause. And historians have praised many aspects of Kennedy’s tenure.