Resting heart rate

Resting heart rate is your heart rate fully at rest; it usually falls as your fitness improves and rises with fatigue, illness or stress.

• Usual range: 60 to 100 bpm in adults, often 40 to 60 bpm in trained runners; the figure itself matters less than your own trend.
• Measure it on waking, lying still, before coffee, or let the Apple Watch estimate it through the day.
• A rise of 5 bpm or more above your usual for 2 or 3 mornings signals fatigue, a coming illness or poor sleep: keep sessions easy.
• Heat, alcohol, a late meal, caffeine and short sleep raise it too.

See a doctor if it stays unusually high or low with dizziness, fainting, palpitations or chest pain.