Key points
- Wearables track useful health data but their readings are estimates, not medical-grade truth.
- Heart rate and other metrics can be inaccurate during high-intensity exercise.
- “Recovery” and “strain” scores are algorithms and should be weighed against how you feel.
- Best use is tracking long-term trends, not obsessing over daily numbers.
By Dr Neil Chapman
Many people these days are sporting smartwatches and fitness bands that count their steps, track their heart rate, monitor their sleep and tell them to push harder or take it easy.
Some people check their watch more often than they check in with their own bodies.
As a self-confessed geek I love my wearable health tech but as an exercise physiologist, I advise against taking their numbers as absolute truth.
Heart rate and other metrics
Heart rate is a good example.
Most watches measure heart rate accurately when you are sitting, walking or doing light exercise, but the harder you work, the less reliable they become.
During high-intensity workouts they can over-estimate or underestimate how hard your heart is working. This doesn’t make them useless, but it does mean you shouldn’t panic or make big health decisions based on a single reading.
Your watch is not an ECG and it does not replace a visit to your GP or a health professional.
Think of it as an early warning system – if something looks unusual or doesn’t match how you feel, that’s your cue to get it checked properly, not to ignore it.
Many devices now show something called “strain”, “stress” or “readiness” – essentially an estimate of how hard your body has worked during the day and how well you have recovered overnight.
These scores are based on algorithms using heart rate and movement data to generate a best guess of how full your internal battery is – useful, but still just a guess.
If your watch says you’re fully charged but you feel exhausted, sore or unwell, listen to your body.
If your watch says you are flat but you feel great, that matters too. The most important data point is still how you feel when you wake up and how you respond when you start moving.
Use trends, not single readings
Where wearables can really help is with habits.
They remind people to move more, sit less and notice patterns over time.
If you see that you sleep badly after late nights or that your heart rate is higher on stressful workdays, that’s valuable data that can spark concrete action.
The danger is becoming obsessed with chasing numbers.
Trying to beat yesterday’s step count or push your strain score higher every day can lead to overtraining and burnout.
Habits over hype
Exercise works because of balance – you stress the body, then you let it recover.
Recovery is not laziness, it’s when your body adapts and gets stronger.
A good rule is to use your wearable to guide decisions, not dictate them.
If your recovery score is low, maybe today is a walk or a swim instead of a hard gym session.
An unusual heart rate could be a prompt to talk to your GP or exercise professional.
You don’t need the latest device to be healthy; people exercised well long before watches buzzed on their wrists.
But if you already own one, use it wisely.
Look for trends, not single numbers, and combine what the watch tells you with what your body tells you.
Listen to your body first
Technology can support your health, but it can’t replace common sense.
Your watch doesn’t know how stressful your week has been, how sore your muscles feel or whether you’re fighting off a cold – you do.
In the end, the best wearable is still your own awareness.
The screen on your wrist is just a tool.
You are the expert on your own body.
* Dr Neil Chapman is an exercise physiologist and Associate Dean of Clinical Services at Bond University.