John Desmond Sinclair (14 March 1927 – 11 February 2018) was a New Zealand neurophysiologist and middle-distance athlete who represented his country at the 1950 British Empire Games.
[4][5] Jack Sinclair was educated at Mount Albert Grammar School, and went on to study at the University of Otago, from where he graduated Bachelor of Medical Sciences in 1948[6] and MB ChB.
[19] On 2 January 1950, at the national athletic championships held in Napier, Sinclair won what was at the time described as "the greatest mile ever run in New Zealand".
His time of 4:13.5 in beating Maurice Marshall and Neil Bates in a closely contested race was a New Zealand resident record, narrowly eclipsing the 4:13.6 set by Randolph Rose in 1926 at Masterton.
[23] Sinclair's early research, as part of his Bachelor of Medical Science studies, was conducted in the laboratory of John Eccles—at that time a professor at the University of Otago and later a Nobel laureate—and was published in the Journal of Neurophysiology in 1949.
He then undertook overseas postgraduate training in respiratory medicine, first at the Royal Brompton and Hammersmith Hospitals in London, and then at the Mayo Clinic in the United States, returning to New Zealand in 1960.
[3][24] Sinclair was appointed the head of the Department of Clinical Physiology at Green Lane Hospital in 1960, contributing to ground-breaking work there in cardiothoracic surgery and medicine.