When it comes to exercising, your heart rate is the gold-standard metric to uncover how hard you're pushing. It tells you whether you're working aerobically or anaerobically, how your body is ...

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After spending 187 hours testing them, these are our top picks. Medically reviewed by Amy Kwan, PT Fact checked by Richard Scherr Medically reviewed by Amy Kwan, PT Fact checked by Richard Scherr ...

Want more tried and tested recommendations from the RW editors? Sign up to our new weekly newsletter Kit Bag. Click here to subscribe. Training smart means mixing up the intensity of your runs ...