Interactive picture of acute responses to exercise in the cardiovascular, respiratory and muscular systems, driven by one exercise intensity control

Stroke volume stops rising halfway, but cardiac output keeps climbing

Exercise does not wait for a warm-up. In the first seconds the lungs, the heart and the working muscle all shift together, and they keep shifting as the effort grows. Raise the intensity and watch the lungs breathe faster and deeper, the heart beat faster and harder, and the muscle warm as it draws a growing share of the blood.

Lungs → heart → working muscle Resting
Raise the intensity. Watch the heart, lungs and muscle respond.
Resting · lactate 1.0 mmol/L
Exercise intensity0%
Rest Moderate Maximal
Heart rate (bpm)
72
Stroke volume (mL)
70
Cardiac output (L/min)
5.0
Ventilation (L/min)
6
Muscle temperature
37.0 °C
Blood to muscle
20%
Which system?

Know This

Within seconds of starting, heart rate, stroke volume lift cardiac output, breathing rate and depth lift ventilation, and muscle temperature, blood flow rise, then all of them return to baseline once you stop.