Not every workout needs to leave you breathless, and for a growing number of people prioritizing long-term health, the opposite is proving to be true. Zone 2 training, a conversational, low-intensity form of cardio, has become one of the most talked-about tools in longevity research.

Zone 2 refers to a heart rate zone, roughly 60 to 70 percent of your maximum heart rate, where the body relies primarily on fat for fuel rather than stored carbohydrates. Training consistently in this zone improves the efficiency of the mitochondria, the energy-producing structures inside cells, which has downstream effects on everything from metabolic health to cardiovascular endurance. It’s a kind of training elite endurance athletes have used for decades to build an aerobic base, now being adopted by everyday people for its long-term health benefits rather than performance alone.

The easiest way to find the right pace doesn’t require a heart rate monitor at all. The talk test is the simplest gauge: if you can hold a full conversation without gasping for air, but singing would feel difficult, you’re likely in the right zone. If you can easily sing along to a song, the intensity is probably too low to count. If finishing a sentence feels hard, it’s time to slow down.

Most research points to somewhere around 150 minutes of Zone 2 training per week for meaningful benefit, which can be broken into three to five sessions depending on schedule. That might look like a 30 to 45 minute brisk walk, an easy bike ride, or a light jog, whatever keeps the heart rate in that steady, conversational range without creeping higher.

Fitting Zone 2 around strength days is simpler than it might seem. Many people pair a Zone 2 session on the same day as a lighter strength workout, since neither type of training significantly interferes with the other’s recovery demand. Others prefer separating them entirely, saving Zone 2 for rest days between heavier lifting sessions as a form of active recovery rather than additional stress.

The appeal of Zone 2 isn’t speed or intensity, but sustainability. It’s a pace nearly anyone can maintain several times a week without burnout, which is exactly why it’s become one of the more trusted long-term strategies for a healthier cardiovascular system.