# Sick days, holidays and unusual periods

Only you mark a sick day; VT never does from your readings. An unusual period explains without changing your baseline.

Type: practice · Domain: Stress, Rest & Recovery · Accuracy: Self-reported · Importance: Core

Also called: sick day, illness episode, unwell, holiday, travel, jet lag, unusual period, annotation, mark a day

## In one sentence

Three ways to tell VT that a day was not your normal, so that your baselines stay honest and your results stay explainable: a sick day, an illness episode, and an unusual period.

## Why this matters more than it looks

Every engine in VT compares you with your own history. A week of being unwell that is not marked becomes part of your normal: your resting heart rate baseline drifts up, your Symptom Radar gets quieter just when it should not, your energy engine reads a few days of eating nothing as a change in what you burn, and your Vitality Score carries forward glucose readings taken with a fever. Marking the days is the single most useful piece of context you can give, and it is also the one VT will never supply for you: only you mark a day as a sick day. However unusual your readings, VT never does it from them.

## The three marks

A **sick day** is a yes or no on the day, with an optional description, for days you were unwell. An **illness episode** is the same thing with a beginning and an end: an onset date, a recovery date, the main symptom (a sore throat, a headache, a stomach bug) and a severity from 1 to 3; it is worth adding on top of the sick days when an illness lasts more than a day or two, because the episode is what Symptom Trend learns from. An **unusual period** is a stretch that was out of the ordinary without your being unwell: a holiday, a conference, a house move, a newborn, a bereavement, a stressful fortnight at work, a week across time zones. When your readings shift, VT asks "Anything going on?"; your answer opens the period from the day of the shift, and after seven days VT asks whether it is still going.

## What each one does

Sick days, and the three days after each, are left out of your Symptom Radar baseline, so a recent illness never becomes your normal; they spoil the night pairs Symptom Trend counts; the energy engine takes them into account; glucose from those days is not carried forward into the Vitality Score; and a day marked unwell pulls the lifestyle area of the Vitality Score down for that week. Illness episodes are kept out of Symptom Trend's reference figures, from 48 hours before onset, and are the record VT uses to check how far ahead of your own symptoms its flags tend to move; the Symptom Radar baseline, the energy engine and the Vitality Score read only the sick-day mark, so mark the days as well. Unusual periods do something different and deliberately smaller: they explain, and they never change a baseline. The readings from those days still count as your normal, because a holiday is part of a normal life.

## What not to mark

A hangover is not a sick day; log the alcohol, and Symptom Radar will give that night's readings less weight. A hard session's soreness is body discomfort, not illness. A late night is a late bedtime, which VT reads from your sleep times. A trip across time zones is best marked as an unusual period, with your bedtime and wake time left to follow the local clock, which VT keeps with its zone.

## When to mark it

On the day, or the morning after, is best; VT also accepts a mark added later, and leaves the day out of every calculation from then on. If you are not sure whether a day counts, mark it: a sick day you did not need costs you four nights of baseline, and a sick day you missed costs you a month of it.

## What happens to the scores afterward

Symptom Radar resumes from your clean baseline the day after the three-day exclusion ends, and may run provisional for a few mornings if the exclusion left a reading short of its seven nights. The Sleep Health Index keeps counting the nights (a disrupted fortnight is an episode, and its regularity multiplier is built for that). Capacity does not leave sick days out of its own baselines. The energy engine never pauses: it gives a sick day a tenth of its usual weight, and the day after half.

## Sources

1. Vitality Tracker, How it works: Symptom Radar and Symptom Trend; the Vitality Score
2. Vitality Tracker, What VT measures (catalogue of 15 October 2026: sickness, illness episodes, unusual periods, and how VT keeps the record).

## Related

- [Symptom Radar and Symptom Trend](https://vitalitytracker.app/knowledge/symptom-radar-and-symptom-trend)
- [Body discomfort](https://vitalitytracker.app/knowledge/body-discomfort)
- [Hydration, alcohol and the diet break](https://vitalitytracker.app/knowledge/hydration-alcohol-and-the-diet-break)
- [The TDEE engine](https://vitalitytracker.app/knowledge/tdee-engine)
- [Vitality Score](https://vitalitytracker.app/knowledge/vitality-score)
- [Sleep Health Index](https://vitalitytracker.app/knowledge/sleep-health-index)
- [Bedtime and wake time](https://vitalitytracker.app/knowledge/bedtime-and-wake-time)

Reviewed October 2026 · v1

Source: https://vitalitytracker.app/knowledge/sick-days-holidays-and-unusual-periods