In the early hours of the next morning, Shackleton summoned the expedition's physician, Alexander Macklin, to his cabin, complaining of back pains and other discomfort. According to Macklin's own account, Macklin told him he had been overdoing things and should try to "lead a more regular life", to which Shackleton answered: "You are always wanting me to give up things, what is it I ought to give up?" "Chiefly alcohol, Boss," replied Macklin. A few moments later, at 2:50 a.m. on 5 January 1922, Shackleton suffered a fatal heart attack.