David Minard, 92, an occupational physiologist who developed a reliable way to measure the effect of extreme heat on humans, died after a stroke Oct. 9 at the Chesapeake Woods Center in Cambridge, Md. He was a Cambridge resident.

Dr. Minard, with Constantin Yaglou, created the wet bulb globe temperature index in 1957 for Marines training at Parris Island, S.C. It is still commonly used as a heat-stress index in the military, steel mills, marathon races and industrial environments. Dr. Minard also put it to use in evaluating the original seven Mercury astronauts in his lab at the Naval Medical Research Institute in Bethesda in 1960.

The index calculates the impact of heat by combining the effects of air temperature, radiant heat from objects in the area, wind and humidity.

Dr. Minard worked at the Naval Medical Research Institute from 1946 to 1963, serving as head of its physiology department, then moved in 1963 to the University of Pittsburgh School of Public Health. He was named professor emeritus in 1974.

Rather than retiring, Dr. Minard entered clinical practice at U.S. Steel in Pittsburgh and at Easton Memorial Hospital until finally retiring in 1980. He wrote numerous journal articles on thermal stress and was a consultant to the National Institutes of Health, the military and various government task forces.

Dr. Minard, who was born in Fargo, N.D., graduated from the University of Chicago and received a doctoral degree in physiology in 1937 and a medical degree in 1943 from the school. He received a master's degree in public health from Harvard University in 1954.

During World War II, Dr. Minard served in the Navy with amphibious forces in the Atlantic and the Pacific fleets. Later in his Navy career, he rose to the rank of captain.

He served as a member of the American College of Preventive Medicine and the New York Academy of Sciences, which recognized his 50 years of service with an award in 1998.

Dr. Minard received the 1960 Gorgas Medal from the Association of Military Surgeons of the United States, as well as the Outstanding Civilian Service Medal from the Department of the Army in 1973 for his service as director of the Commission on Environmental Health of the Armed Services Epidemiological Board.

He also was an accomplished photographer and sailor.

His marriage to Sally Zimmermann ended in divorce. A son, Nicholas Minard, died in 1975.

Survivors include his wife, Dorotha Rittenhause Minard of Cambridge; three children from his first marriage, David Minard of Needham, Mass., Michael Minard of Katonah, N.Y., and Rebecca Minard of Providence, R.I.; a stepson, Michael Fallon of Annapolis; a stepdaughter, Michelle Sposato of Columbus, Ohio; eight grandchildren; and one great-grandson.