Wearables

Your watch counted the walk. It missed the workout.

Ten minutes of walking to the gym: logged. Ninety minutes under a bar: 'Were you exercising?'

Wrist sensors read arm swing

Accelerometers love rhythm — steps, strides, pedal strokes. A heavy set of five reads as twelve seconds of stillness with a scared heart.

Heart rate is not effort

Lifting spikes and recovers in waves the calorie model was never built for. The number it prints for your session is a shrug with decimals.

So the hardest work scores lowest

The stimulus that actually changes your body — progressive overload — is the one your wrist is worst at seeing. Easy cardio wins the rings; hard training builds the body.

Score the output, not the wave

Your logbook knows the work. Your body shows the result. Between them, the watch's guess about Tuesday is the least useful number you own.