Crash / PEM tracking

Post-exertional malaise (PEM) is a worsening of symptoms after physical or mental exertion. Crash/PEM tracking helps you log these episodes and see how they relate to your activity levels.

Enabling PEM tracking

During onboarding, Crash / PEM Tracking starts on for ME/CFS, Long COVID, Fibromyalgia and POTS. You can turn it off in Customise your journal or change it later in More > Tracking. Going Back or changing starter items keeps your choice; changing conditions updates these defaults.

Logging a crash

In the entry editor, toggle “Crash / PEM” to mark a crash day. Crash days are automatically treated as flare days regardless of your day rating.

How PEM affects your data

PEM/crash days are always counted as flare days in correlations and patterns. A day rated 4 with a PEM crash is still a flare day — this ensures your pattern analysis accounts for crashes even on days that otherwise felt manageable.

Your personal PEM delay

After you log 3 or more crashes and record an earlier exertion date you suspect may be relevant, Tended summarises the time between those records. You’ll see the median interval, range, a distribution chart, and breakdowns by the context you recorded. Find it on the Insights tab under “Post-exertional crashes.”

PEM suggestion prompt

When you create an entry with a low rating or low energy after a busy day, Tended may ask whether you want to record the day as post-exertional. Tapping “Yes” marks the entry as a PEM crash and pre-fills the earlier exertion date for you to check. The prompt records your judgement; it does not diagnose PEM or establish a cause.

Record a PEM crash

Record a crash or PEM experience in your own words.

If a field you want is hidden, enable it in More > Tracking. Only turn on what you want to use.

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Record a PEM crash: steps

1. Check the date The guide opens a new journal entry. Check its date and time before adding details. You can also use this guide while editing an existing entry.
2. Open Crash / PEM Find Crash / PEM and mark the entry only if it describes the experience you want to record.
3. Keep cause optional Review any suspected activity or date and add context if useful. A suspected link is not a confirmed cause.
4. Save your entry Return to the entry and tap Save. Wait for it to close. The guide completes only after the relevant new or changed detail is saved.

Record a PEM crash: troubleshooting

If the guide has not finished, check that you changed the relevant field and saved the entry. Simply reopening an existing value does not count. If Save fails, keep the draft open and use Try Again.