Cardio

Grade, not habit, should decide when you run a climb and when you hike it — here’s the heart-rate and gait math behind that call.

Couch to 5K’s graded weekly intervals raise VO2max the same way comparable six-to-nine-week aerobic trials do, before blood pressure follows.

Compare calorie burn, heart load, bone gain, knee pain, and recovery to build your weekly cardio mix.

Set 1% for fast runs and 4-12% hills to lift heart rate and match outdoor effort on any treadmill.

Compare heart-rate accuracy, VO2 max tools, training scores and battery to pick your running watch.

Learn how to start, build base miles safely, and choose a training timeline that fits your fitness.

Garmin Training Readiness rolls six inputs, from last night’s sleep to HRV status and acute load, into one 1-100 score. Here is what Garmin says each input is, what the bands mean, and when your body should overrule the number.

See why new runners gain heart and leg fitness fast, and how to raise mileage without injury.

Learn how to adjust pace, pair effort with heart rate, and keep hot-day runs safe and productive.

Learn how much VO2 max adults over 60 gained, why aging caps it, and how to train for it safely.