BSc Lond 1926, MB BS 1932, MD 1935; MRCP Lond 1934.
Sykes gained his medical education at Manchester and held junior appointments at MRI and Ancoats Hospital. He then held resident appointments at the Brompton Hospital for Consumption and Diseases of the Chest, Withington Hospital and MRI. Sykes was a major in the RAMC from 1942 to 1946, serving in England, North-West Europe, and Africa, where he gained experience of tropical diseases. After demobilisation, Sykes returned to Manchester and was honorary physician to Manchester Northern Hospital and Oldham Royal Infirmary. He was later appointed consultant physician to Stockport Infirmary and Stepping Hill Hospital. Sykes was a member of Manchester Medical Society and of the Thoracic Society.