Sleep, recovery and strain explained: how to read your scores

Wearables give you many numbers. These are the ones that matter for training and how to read them without panic.

Resting heart rate

Your heart rate when you are calm and still, usually lowest during sleep. A resting heart rate that is several beats above your usual often means stress, illness, poor sleep or too much training. Compare it with your own average, not with other people's.

Heart rate variability (HRV)

HRV measures the small differences in time between heartbeats. For most people a higher HRV than usual means the body is relaxed and recovered, and a much lower one means it is under strain. Individual values vary a lot, so only your own trend matters.

Sleep

• Duration. Most adults need about 7 to 9 hours.
• Deep sleep is the physically restoring stage.
• REM is linked to memory and mood.
• Regular wake-up time helps your body clock. A steady schedule can improve sleep quality more than a single long night.

Recovery score

A recovery score combines your resting heart rate, HRV and sleep and compares them with your own recent normal. A high score says you are ready to push. A low score says to keep it easy. Lift Log shows recovery as green, yellow or red.

Strain score

Strain estimates how hard the day was on your heart, based on how much of your heart rate range you spent time in. Lift Log shows it out of 21 and gives you a target range based on how recovered you are.

Using it day to day

To get these numbers from a band, see Fitbit Air and Health Connect.

Wearable scores are estimates and are not a medical device. If a number worries you, or you feel unwell, speak to a doctor.

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