Total peripheral resistance goes down during exercise as the arterioles supplying muscle and skin dilate.

Exercise physiology (UWorld)

Increase muscle activity causes:

• Venous constriction --> increase preload
• Increase cardiac contractility and HR

Both --> increase cardiac output

• Resting muscle and splanchnic vasoconstriction
• Arteriolar dilation within muscles (lowers total systemic vascular resistance)

Both --> increase blood supply to active muscles