[5] While working under mentor and department chair Warfield Theobald Longcope, she studied neurogenic models of hypertension and the effects sympathectomy has on blood pressure.

[6] Thomas simultaneously served as a physician at the Bryn Mawr School, a civilian consultant to the Army Surgeon General, and operated a private practice.

"[6] Between the years of 1948 and 1964, Thomas conducted studies on 1,337 Johns Hopkins students and graduates, mostly made up of young, white males, in order to limit confounding factors.

The original aim of the study was to determine precursors of heart disease by subjecting each participant to a series of physical exams and an 11-page questionnaire about eating and lifestyle habits, family history, and psychosocial characteristics.

[7] The results of her research found that of the males studied, those who developed coronary artery disease also had high cholesterol but not vice versa.

She also found that graduates who suffered anxiety or depression as students were more likely to be fatigued and achieve lower academic standings.