The talk test
is a way to measure relative intensity of an activity, and it relies on understanding how physical activity affects heart rate and breathing, according to the US Centers for Disease Control and Prevention.
Generally, being able to talk but not sing during an activity would make it moderate intensity, the CDC says. Your voice might be labored, said physical therapist Nicholas Rolnick, but you can carry on a conversation. “It’s (your) heart rate elevated, but not interfering with a workout,” said Rolnick, who’s based in New York City.