Physical activity leads to a respiratory behaviour that is very different to a resting state and that influences speech production. How speech parameters are exactly affected by physical activity remains largely unknown. Hence, we investigated how several prosodic parameters change under influence of physical activity and focused on temporal and breathing characteristics which have not been addressed in detail before. Speech from subjects reading aloud a text before and after a treadmill running exercise was analysed for prosodic differences between before and after running. The most important findings include a higher articulation rate, longer averaged pause and breath durations, a higher in-breath intensity, a higher out-breath rate, and a higher mean F0 for speech recorded immediately after vigorous treadmill running. These findings provide fundamental insights into how speech characteristics are affected by physical effort, and may help advance automatic classification of physical stress in speech.