Sleep studies
Actigraphy explained
A wrist-worn movement sensor worn for one to two weeks that maps your real-world sleep patterns.
Key facts
At a glance
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What it is: a watch-like device recording movement and light continuously for 7-14 days, paired with a simple sleep diary.
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Best for: suspected body-clock disorders, irregular schedules, insomnia assessment and checking sleep duration claims objectively.
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What it is not: a breathing test - it cannot diagnose sleep apnoea.
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Results: analysed after the wear period, with a report typically within a week of returning the device.
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Follow-up: a sleep specialist reads the rhythm - delayed sleep phase, shift-work patterns or fragmented sleep - and tailors treatment accordingly.
The full picture
What this test involves, and how to get it
Actigraphy answers a question single-night studies cannot: what does your sleep actually look like across weeks of ordinary life? A wrist-worn accelerometer, usually with a light sensor, records continuously for one to two weeks while you keep a brief diary. The analysis maps when you genuinely sleep and wake, how regular the pattern is, and how fragmented the nights are. This makes it the test of choice for circadian rhythm disorders - the night-owl physiology of delayed sleep phase, advanced phase in older adults, shift-work disruption - and a valuable objective check in insomnia, where perceived and actual sleep often diverge, a mismatch that itself guides therapy.
Consumer wearables estimate similar things, but clinical actigraphy uses validated devices and standardised scoring that sleep physicians can act on, including for decisions about melatonin timing and light therapy scheduling, where the intervention only works if aimed at the right point of your body clock. Actigraphy cannot detect breathing problems, so it complements rather than replaces apnoea testing. NHS access runs through sleep and circadian clinics, which are few; private sleep services can issue a device within days, with a consultant interpretation after the wear period and a concrete plan - timed light, scheduled melatonin, behavioural restructuring - built on two weeks of your actual life rather than one strange night.
A quiet reminder
This guide is for information, not medical advice.
Your own clinician knows your history and can tell you which parts apply to you. Next review of this page: 2027-09-27.
Frequently asked
Common questions about Actigraphy explained.
Quick, plain-English answers to what people ask us most.
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What is Actigraphy explained and what does it record?
Actigraphy explained is a monitoring test that records a specific body signal continuously or intermittently over an extended period, rather than at a single moment in time. This gives doctors a much fuller picture than a brief in-clinic reading can, particularly for symptoms that come and go. The exact duration and what's recorded depends on what your doctor is trying to capture.
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Why would a doctor request this kind of monitoring?
It's typically used when symptoms are intermittent or unpredictable, making them hard to catch during a single short appointment. It helps doctors correlate what you're feeling with what's actually happening physiologically at the time. Your doctor will explain what specific pattern or event they're hoping to capture.
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Do I need to do anything to prepare?
Preparation is usually minimal — you'll typically be shown how to wear or use the monitor and given instructions on what to do (or avoid) during the monitoring period. You may be asked to keep a diary of symptoms or activities alongside the recording. Following the specific instructions given helps ensure the results are as useful as possible.
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What happens while I'm wearing or using the monitor?
You'll generally be able to continue with most normal daily activities while the device records in the background. You may be asked to avoid certain things, such as bathing with the device on, depending on the type used. Staff will give you clear instructions on what's allowed and what to note down.
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Is it uncomfortable or does it carry any risk?
Most monitoring devices are lightweight, non-invasive and designed to be worn comfortably for the required period, with only mild skin irritation being a possible minor issue for some people. Serious risks are very rare with this type of monitoring. Let the clinic know if you experience any discomfort so they can adjust the device if needed.
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How long until I get my results?
Once the monitoring period ends and the device is returned or downloaded, the data usually takes a few working days to be analysed and reported by a specialist. More complex or lengthy recordings may take slightly longer to fully interpret. The clinic will confirm the expected timeframe when you're set up with the monitor.
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What happens if the monitor picks up something abnormal?
A specialist will review the recording and explain any findings in the context of your symptoms and history. Not every abnormal reading requires treatment — some are common and harmless, while others may need further investigation or follow-up. You'll be talked through what, if anything, needs to happen next.
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Is this available on the NHS?
This type of monitoring is generally available on the NHS, though there can be a wait for referral, the monitoring period itself, and result review. Private providers can typically arrange monitoring within days and often provide quicker specialist review of the results. Cost for private monitoring varies by provider.
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How reliable is this kind of monitoring?
This is a well-established and clinically reliable way of capturing patterns that a single snapshot reading would miss. Accuracy depends partly on the monitor being worn correctly and consistently for the recommended period. Your clinic will explain how to get the most useful recording from your monitoring period.
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How do I arrange this kind of monitoring privately?
You can typically arrange this directly with a private clinic, often without needing a GP referral, with fitting appointments usually available within days. The clinic will explain how the device works, how long you'll wear it, and when to expect your results. Contact the clinic to check current availability.