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.
It's an easy method of scaling intensity without any complicated fitness technology or software, Rolnick said. The talk test can help you "make sure that you're hitting the intensity of exercise that you want to hit in order to meet physical activity-recommended guidelines."
This activity could look like walking briskly, or 3 miles per hour or faster, but not speed-walking. Water aerobics, biking slower than 10 miles per hour on flat or level ground, tennis and ballroom dancing might also fit into this intensity level, according to the CDC.
During the most intense workout, carrying on a conversation would be impossible, Rolnick said. You wouldn't be able to say more than a few words without having to pause for a breath, the CDC says.
Exercises done to that intensity can include running, swimming laps, singles tennis, aerobic dancing, bicycling faster than 10 miles per hour or on inclines, jumping rope or hiking uphill or while carrying a heavy load.
Pregnant people should do at least 150 minutes of moderate aerobic and strengthening exercises per week, the WHO recommendations say. And children under 18 need at least 60 minutes of moderate-to-vigorous exercise (mostly aerobic activities) daily.