Pacing apps for smart watches – part 1

Pacing apps for smart watches – part 1

For people suffering from Post-excertional Malaise (PEM) as a result of Long COVID or ME/CFS, pacing is key to avoiding crashes. A pacing app for smart watches can help people to better recognize their own limits.

Pacing is at the heart of the treatment of many post-viral diseases, such as Long COVID, and other diseases associated with fatigue and/or exercise intolerance (PEM, Post-excertional Malaise), for example Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS).

For people suffering from fatigue, pacing can help to better manage their available energy resources and to tackle everyday activities and tasks by incorporating rest periods and breaks into their daily schedule.

If you have PEM, pacing is essential to avoid crashes. To this end, it is crucial to always respect individual limits and never exceed them. A good balance between physical, cognitive, or emotional efforts and resting time must be established.

It is important to note that fatigue and PEM can occur simultaneously, but both symptoms can also appear individually.

  • People with Fatigue feel permanent tiredness and exhaustion, which does not improve through rest and sleep. For some, this exhaustion is constant. If PEM is also present, exertion leads to a severe worsening of symptoms, a crash.
  • People with PEM experience crashes after certain exertions without necessarily suffering from general exhaustion/fatigue. The type of exertion that leads to the crash can also vary. Some people react particularly strongly to cognitive exertion, while others only experience a crash after physical exertion.


Monitoring your heart rate can help with pacing and assessing your own limits. As soon as a certain heart rate is exceeded during an activity, a break should be taken.

These breaks can vary greatly depending on the condition of the person affected. For people who only have mild symptoms during physical exertion and are even able to exercise, a break can mean sitting down briefly whenever the self-defined maximum heart rate is exceeded.

For people whose crashes are mainly triggered by cognitive exertion, a break can mean sitting down in silence for a few minutes with your eyes closed after reading.

For particularly severely affected people, sitting upright for even a short time can cause overexertion and drive up the pulse. In this case a resting phase lying down with as few environmental influences as possible (no noises, no light, optimum temperature, etc.) might be necessary.

It is particularly difficult to find the cause of crashes, as they often occur hours later.

Healthy people usually notice exhaustion immediately after a demanding activity. This makes it easy to recover quickly from exhaustion or to avoid that kind of activities, as the effects are felt immediately.

In people who suffer from PEM, a crash often occurs a few hours or even days after the exertion. This makes it very difficult to understand afterwards which activity actually caused the crash.

An energy and activity diary can help to identify activities that drain a lot of energy. However, keeping such a diary can also lead to overexertion. Moreover, even with a detailed diary, it is often not obvious which of the activities led to the crash.

Heart rate monitoring can help to better determine activities and their energy requirements. Additionally, in the event of a crash, it can help to better assess what caused the crash. If the recordings show that an activity has increased the heart rate particularly strongly, it is very likely that this activity triggered the crash.

In Switzerland, 2 apps for smartwatches are being developed that can help with heart rate monitoring.

Fitness trackers or smartwatches that continuously measure and record the pulse on your wrist can help with heart rate monitoring. There are currently two apps in Switzerland that are addressing this.


The MindfulPacer from the University of Zurich

Two researchers from Zurich, André Meyer-Baron and Carlo Cervia-Hasler, are working on the development of a pacing app in conjunction with a smartwatch application. The app is still in the pilot phase and feedback from representatives of the patient organization Long COVID Switzerland, who have tested the application in a test phase, is currently being implemented.

The MindfulPacer combines an energy and activity diary with continuous heart rate monitoring. In the app, patients can keep a diary of their daily activities, assign a corresponding energy level to each activity, and indicate how they felt when carrying out that activity. At the same time, the heart rate is recorded by the smartwatch application and assigned to the respective activity.

This means that users can later see in the statistics which activity consumed how much energy at what time of day and how their heart rate was affected by that. The tracking makes it easier to find out which activities are particularly energy-consuming and when breaks are necessary.



Screenshots of the MindfulPacer application.


It can often be difficult to estimate how much energy is being used, especially for activities that bring a positive feeling. The subjective perception of energy consumption can be lower than the actual energy consumption.

Particularly in these cases, it can help to monitor the impact of the activity on the heart rate in order to determine the actual energy consumption more accurately and avoid crashes.

For better control of the heart rate, personal alarms can be set that give a signal, e.g., by vibration or color display on the smartwatch, when a certain frequency is exceeded. Each patient must determine a suitable limit individually.

The first version of the app will be available for Android systems, but a transfer for Apple devices and other smartwatch providers is in progress. The app is not yet freely available but will be released as soon as the test phase is complete.


We will be discussing another app developed in Switzerland and applications that are available internationally in Part 2 of this blog.