Background: Physical exercise alters many biochemical parameters of human body. For that reason, it is recommended as a cure for many diseases of modern life like obesity and diabetics. This study investigates the biochemical and hormonal changes in diabetic, hypertensive and obese individuals after Bruce treadmill tests of different durations and intensities. Method: Our sample consisted of 59 individuals, divided into four groups: A: 12 normal body-weight diabetics, B: 11 overweight diabetics, C: 14 normal body-weight non-diabetics and D: 22 overweight non-diabetics. 66.1% of them were men. The comparisons were done between: 1) Diabetics versus non-diabetics; 2) Over-weight versus normal body-weight persons; 3) Over-weight diabetics versus normal weight diabetics; 4) Over-weight non-diabetics versus normal body-weight non-diabetics of 5) Hypertensives versus non-hypertensives. All individuals performed an intense, short duration treadmill exercise test, independently of the presence or not of DM2, hypertension and obesity. Results: The participants with DM2 (obese and non-obese) had decreased levels of glucose, triglycerides and TSH (P < 0.01) and increased levels of HDL-cholesterol, CK, CK-MB, LDH, renin, aldosterone (P < 0.01) after Bruce test. The nondiabetics participants (obese and non-obese) had decreased levels of glucose, urea, triglycerides, CK, CK-MB, LDH (P < 0.01) and decreased levels of hematocrit, HDL-cholesterol (P < 0.01) after Bruce test. All the other alterations have no statistical importance. Conclusion: Our results proved that the physical exercise, even if it has short duration like that of the Bruce test, has beneficial results in persons with DM2, obesity and arterial hypertension, as well as in normal persons.