Brisk is not one speed for everyone
You head out for a walk and hear that it should be “brisk.” How brisk? Keeping up with someone else tells you their pace, but not how hard you are working.
The CDC distinguishes absolute intensity, based on the energy an activity uses, from relative intensity, based on the effort it takes for you. The same activity can feel moderate to one person and vigorous to another. [1] A pace on a screen leaves out that difference.
Listen to the conversation
For aerobic activity, the CDC offers a simple rule of thumb: at moderate intensity you can talk, but singing is difficult. At vigorous intensity you need a breath after just a few words. [1] This is the talk test. It gives you a rough guide without a heart-rate monitor.
On a familiar, safe stretch of your next walk, notice whether you can speak a normal sentence while moving. There is no need to sing in the street or turn the outing into an exam. If your aim is a moderate walk and conversation is breaking into a few words at a time, ease the pace and check again. This is a practical use of the guideline, not a personalized training prescription.
The person beside you may be working harder
The NIH explains that intensity depends on the effort an activity takes: people with lower fitness generally have to work harder to do the same activity. [2] Walking together does not guarantee that you are training at the same relative intensity.
If one of you can chat easily and the other can barely answer, agree on the effort you want to share rather than defending a speed. “I want to keep talking on this stretch” is a clearer request than “walk at my normal pace.”
What the test cannot tell you
The talk test describes aerobic effort. It does not measure calories, diagnose fitness, or tell you how many good push-ups are left in a set. The NIH distinguishes aerobic activity from muscle-strengthening activity, while noting that some activities can involve both. [2] Do not turn one breathing cue into a score for your whole workout.
Nor is difficult breathing a target you must reach for a walk to matter. Start with one observation: what happened to your conversation at the pace you chose? If breathlessness is unusual or worrying, stop and seek medical advice instead of using this test to explain it away.