HRV, pacing and why Coji hasn't added it yet
What a heartbeat measurement can tell you, and the questions Coji needs to answer before using it.
When your energy changes from day to day, a number that might help explain it can be appealing. Heart rate variability, or HRV, is one measurement you may have seen on a watch or in a recovery app. Coji has deferred HRV integration. Its energy forecasts currently exclude wearable health inputs, and your own energy check-in takes priority over an estimate. Here is the thinking behind that approach.
What is going on
What HRV measures
The gaps between heartbeats vary.
Heart rate counts beats per minute. HRV describes variation in the time between successive beats. Shaffer and Ginsberg's research overview explains why interpretation depends on context: breathing, posture, recording length and measurement method can affect the result. Different HRV measures describe different aspects of that variation. A value recorded one way cannot simply be swapped for a value recorded another way.
→A single HRV number is not a direct measurement of how much everyday activity you can manage.
Where pacing fits
Start with the energy and symptoms you actually experience.
For people with ME/CFS, pacing means managing activity within personal limits to reduce post-exertional malaise, often shortened to PEM. PEM is a worsening of symptoms after physical or mental effort; it can arrive later rather than during the activity itself. The CDC describes activity and symptom diaries as one way to identify personal limits. NICE advises against programmes that impose fixed increases in activity or exercise for ME/CFS. This is different from a fitness plan that raises a target each week.
→HRV and heart-rate monitoring are different measurements. Neither should be treated here as a personalised activity limit or permission to push through symptoms.
Why Coji has deferred it
Adding another input needs to earn its place.
Coji is first evaluating forecasts against the energy people report themselves. Before HRV could be useful inside that system, it would need a reliable way to arrive from a device, a clear record of how it was measured, and evidence that it improves the forecast for the person using it. General research on HRV does not establish that a Coji feature would help someone pace. That is a separate question to test. Current development keeps those wearable inputs out while that work remains undone.
→Your reported capacity stays authoritative. A physiological measurement would not override it.
What would need to change
Evidence and control come before an integration.
Any future wearable connection would need its own optional permission, a clear explanation of its purpose, and a way to disconnect it and remove its data. It would also need testing that distinguishes an accurate forecast from a forecast someone actually finds helpful. These are requirements for future consideration, rather than an announced feature or a release date. For now, Coji works without an HRV device.
→A useful feature should give you more understanding and control over the information you share.
What this could mean in practice
Keep your own experience in the picture
A number needs context.
If you already use a wearable, an HRV reading can be something to discuss alongside your symptoms and activity history with a clinician familiar with your condition. This article offers general information, rather than an individual pacing plan. Coji does not provide medical activity thresholds or establish that an activity is safe for you.
How does this information fit with my symptoms and the support I already use?
Your energy check-in remains your account of how you feel today.
Have experience of pacing or wearable tracking? You can share what has been useful, confusing or tiring in the Coji Reddit community. Share only what you are comfortable making public.