This paper examines how speech rate increase acts to change speech rhythm at the articulatory level. Main results show that speech rate increase worked to change articulatory parameters in the following way: a) decrease of acceleration duration; b) decrease of y-extremum; c) decrease of constriction displacement; d) decrease in modulus of peak and/or valley velocity; e) decrease of gestural duration; and f) constant proportional time-to-peak (or valley) velocity. Besides, results have shown that speech rate tends to affect all gestures in an utterance independently of their phrasal position. Nevertheless, there was evidence that some articulatory parameters could, if properly manipulated, provide cues for rhythmic restructurings in speech. Finally, results show that the dynamical speech rhythm model (Barbosa, 2007) is more appropriate to deal with Brazilian Portuguese acoustical data than the pi-gesture model (Byrd &Saltzman, 2003), and that both models could explain articulatory reorganizations due to speech rate increase.