CARDIO BY NUMBERS

If your stamina sessions have become weighed down by distracting data from your smart watch, don’t sweat it. Our exertion scale is the only tracker you need because – as science confirms – if it feels like hard work, it is.

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Warm-up Skip static stretching: studies show it can hamper endurance. Instead, get your joints moving by running your first mile at a gentle pace. Conversations about last night’s GOT should feel like a breeze.

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Steady effort Conversation may come in gasps, but this is where the runner’s high lives. By slogging at this pace three times a week, you’ll also outpace mental decline, the University of Pittsburgh found.

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Hard push The real work starts here. Hitting the lactic threshold will have you breathing in short, sharp breaths. You’ll force the body to adapt, boosting both anaerobic fitness and muscle strength to help you stay strong.

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All- out Burning lungs define the dash to the finish. But think of your abs: according to the Uni of Arkansas, this is prime territory for searing abdominal fat. Plus, sprints do wonders for your VO2 max.