The Oral Glucose Tolerance Test is a commonly used test for diagnosis of Impaired Glucose Tolerance and Type 2 Diabetes Mellitus. In practice, there are two standard sample time intervals: deltat=60 min and deltat=30 min and two standard test time durations: 120 and 180 min. However, for an accurate description of blood glucose concentration dynamics, this number of samples is not enough. In the present work, test duration is considered beyond 180 min and a shorter time interval of deltat=10 min is proposed. Two main hypotheses are discussed: (a). Blood glucose concentration dynamics can be viewed as the impulse response of a "black box" system where the output is conformed by the algebraic sum of a set of exponentially damped sinusoidal functions and (b). There exists at least one endogenous excitation that acts as a counterregulatory mechanism against hypoglycemic tendencies.