Sleep tracking: use and limits

It's Tuesday morning and your watch tells you that you got a "low sleep score" last night. Maybe you feel fine anyway. Maybe you feel wrecked. Either way, it's worth understanding what these devices can and can't tell you.

What it is

Sleep tracking uses a wearable device, a phone app, or a mattress sensor to estimate how long you slept, how restless you were, and roughly what sleep stage you were in. Most consumer devices use movement and heart rate to make educated guesses. They can be genuinely useful for spotting broad trends over weeks - for example, a habit of going to bed later on weekends, or waking often in the small hours.

Signs to notice

• You check your sleep score first thing and it sets your mood for the whole day.
• You feel anxious or annoyed when the app says you slept "badly", even though you feel okay.
• You keep changing your routine to chase a higher number.
• You treat the stage breakdown (light, deep, REM) as a precise clinical result.
• You lie awake worrying about your sleep instead of resting.

What helps

• Use tracking data as a rough trend line, not a daily verdict. Patterns over two to four weeks tell you more than any single night.
• Trust how you feel during the day - your energy, mood and concentration - as much as any score.
• Remember that consumer trackers estimate sleep stages from movement and heart rate, not brain activity, so stage data is only an approximation.
• If a tracker is making you more anxious about sleep, take a break from checking it, or hide the score and just glance at the data weekly.
• Use trends to inform simple, practical changes, like a more consistent bedtime, rather than chasing a perfect score every night.
• Some workplaces and wellness programmes use sleep data to encourage healthy habits - if yours does, remember the number is a nudge, not a judgement of your worth or discipline.

When to reach out for help

If you regularly feel exhausted despite what looks like enough sleep, if you snore loudly or gasp for air at night, or if worry about sleep is affecting your mood, work or relationships, it's worth talking to a professional. A doctor or sleep specialist can assess for conditions a tracker cannot detect, such as sleep apnoea.

Getting help in South Africa

Speak to your GP about persistent sleep concerns, or reach out to your Cleared Mind EAP counsellor for support with anxiety around sleep or general wellbeing. SADAG's Mental Health Line (011 234 4837) can also help if sleep difficulties are tied to stress or low mood.