Stress Load and daytime stress

What Stress Load is#

Stress Load (Czech "Stresová zátěž") is one of our health indices. Higher is worse, so on the screens where a high number has to mean a good day (the Body Status tiles, readiness) it is shown turned around as Calm (Czech "Klid"), which is 100 minus Stress Load. A Stress Load of 33 is a Calm of 67. The number is the same, only the direction differs.

Two different things carry the word "stress" in the app, and it helps to keep them apart:

• The stress readings of your device. A number a watch or ring makes from your heart rate and its variability while you are still. We show it under the device's name and never as ours.
• Stress Load. Our composite, built from those readings and from other signals. It is modelled, not measured.

Where you see it#

• Body Status: the tile "Calm" under "What the state stands on", and the words "high stress" in a Steady day's list of things to watch. Peak Day needs Stress Load under 35, Strong under 55, and the floor under both is 65 (Body Status).
• Training Readiness: 15 % of it, taken as 100 minus Stress Load (Training Readiness).
• Overview banner: at a Stress Load above 70 you see "High stress load (72). Cut back on commitments today where you can." It stays on the free plan.
• Trends: the "Stress" tile. It is not a level: it shows how far your device's stress sits from your own average of the days before the period (up to 90 days back), in per cent, and a rise against the previous period turns red.
• Health tab: the heart-rate chart "Heart rate through the day" colors the line by stress where Garmin measured it (below), and an Oura ring adds "Daytime stress by Oura".
• Overview energy map: "Day stress: 30" beside the legend (Morning Energy).

Everything except the banner and the verdict words in Body Status is Premium, see Free and Premium.

Where stress readings come from#

From a Garmin export we publish a day's average only when the watch's samples cover at least 70 % of the day, because a morning-only mean runs low and an afternoon-only mean runs high. The peak and the span are kept on any coverage.

Garmin puts no stress into Health Connect, so a Garmin reaches us through its own link, an export or the watch app. If your device sends no stress index and no Body Battery, you have no Stress Load. A sleep-fragmentation part alone is a single substitute for stress and never makes the index (see the minimum).

The "Felt stress" answer in your check-in is for you and for your patterns. It is not part of Stress Load.

Garmin's four bands#

Where a Garmin delivers the 0 to 100 index, the band words are Garmin's own:

The Czech words are "klid", "nízký", "střední" and "vysoký". On the Health tab's heart-rate chart these are the colors under "Stress (Garmin)". Oura's minutes have no published scale, so we never put a band on them: a number of minutes is read only against your own days.

How Stress Load is built#

The eight parts#

Body Battery is the 0 to 100 energy level a Garmin watch keeps: it charges overnight and drains through the day (Morning Energy).

The weights add up to a little over 100 % (108), so the average is divided by the weights that are present: a part you do not have drops out and the rest count for more.

• Average stress (30 %). Only the 0 to 100 index (Garmin, COROS) or, for an Oura ring, minutes. For the index we take the average of the last 5 days that have ended, each day counting 85 % of the day after it (a reading 2 days back counts 72 % as much). The average goes on the stress ladder below, then your newest day shifts it by up to 20 points against your own 30-day usual and spread, and the result is turned around so that more stress means a higher Stress Load. For Oura minutes there is no ladder: only the newest day's minutes against your own 30-day usual and spread, and nothing at all while there is no usual yet.
• Stress trend (18 %). The 5 days that ended, against the 5 days before them. For the index the step is 3 points per point of change in average stress, placed around 50: a fall of 4.4 points is 50 - 13.2 = 36.8. For Oura minutes it is 60 times the per cent change. It needs at least 5 readings across the two halves and some in each.
• Energy used against recharged (20 %). The Body Battery drained divided by charged, times 50, over the window, so a day that drains as much as it charges is 50. A partial day, where the drain is under 30 % of the charge, is skipped.
• Peak stress (10 %). The average of the daily highest readings, minus 60, times 1.2: a daily peak of 85 gives 30, 100 gives 48.
• Energy drained (10 %). The average drain minus 15, times 1.5: a drain of 50 gives about 52.
• Morning battery deficit (8 %). How far this morning's Body Battery is under your own 30-day usual, in your own spreads: at or above the usual 0, two spreads under 100. It needs a usual with a spread.
• Time awake (8 %). The share of the night you were awake, turned into a sleep-efficiency score on the app's one efficiency ladder (92 % efficiency or better gives 90 to 100, 85 to 92 % gives 70 to 90, 75 to 85 % gives 40 to 70) and turned around. A night whose awake time the device does not measure is left out, never counted as a perfect night.
• Spikes (4 %). The average gap between each day's peak and its average, minus 30, times 1.5: a gap of 50 gives 30.

The stress ladder#

The ladder maps the 0 to 100 index onto a 0 to 100 score where higher is calmer, following Garmin's own bands. Stress Load is that score turned around.

The ladder is the level and your own usual only shifts it, by up to 20 points: a week at an index of 60 scores as a week at 60 even if 60 is your habit.

Which days are read#

• Stress parts read days that have ended. Today is left out, because a day still running would look calm in the morning and heavy at night, and the number would move through the afternoon. The window is the 5 calendar days before today. If those 5 days hold no stress reading at all and you have older data, it widens to 10 days.
• Body Battery and sleep parts read the last 5 days including today, because they describe the night that just ended. The Body Battery sums of a day that has not ended are withheld.
• Days, not rows: a gap in your data is a gap, not a different week.

The minimum#

• At least 2 days with data in the window, otherwise the index shows "No recent data" and the day it was last measured.
• At least 2 parts. A single part is one substitute for stress and not the quantity, so the index is withheld. Typically this means: no stress index and no Body Battery, no Stress Load.
• With 2 parts the score keeps 60 % of its distance from 50, with 3 parts 80 %, with 4 or more all of it. A raw 75 on two parts is shown as 65.
• A stress reading of zero is a reading, the calmest day, and counts. It is not "no data".

What the number does#

• Body Status. Stress Load under 35 is one of the conditions of Peak Day, under 55 of Strong, and 65 or more closes both and appears as "high stress" in a Steady day's list. A device with no stress index is not held back for it (Body Status).
• Training Readiness. Calm counts 15 % (Training Readiness).
• Recovery does not use Stress Load. It reads the stress index again, on its own, with a 10 % weight (Recovery). The two can differ.
• The banner above 70.
• HRV panel. "After a high stress day" compares the nights after your top quarter of stress days (HRV).

Daytime stress in the app#

• Heart rate through the day. Where Garmin sent the day's stress in 5-minute steps, it colors the line (rest, low, medium, high) while you are still, and the heart-rate zone colors it while you move. The legend reads "Stress (Garmin)" and the day's key names the bands you had. This is Garmin's reading, shown as Garmin's.
• Daytime stress by Oura. A card with the minutes in elevated stress ("tense"), a trend ("falling trend (less time tense)", "rising trend (more time tense)", "stable") and a strip from "calmer" to "tenser". The card says it is "not our modelled Stress Load. Less is better."
• Day stress. The average of the day beside the energy map's legend.

What changes it#

What moves Stress Load is what moves its parts:

• more or higher stress readings from your device, which it works out from heart rate and heart-rate variability, so a pulse that climbs for reasons other than worry, such as on standing up, can read as stress;
• a Body Battery that drains fast compared with how much it charges, and a low battery in the morning;
• a restless night, with a lot of time awake;
• a trend of rising stress over the last days;
• sharp peaks above your average.

A calm week with good nights, a full recharge and few peaks gives a low number. One day is one reading among five, though the newest day counts most.

When it updates#

Stress Load is worked out when your night arrives and again when new data arrive. Because the stress parts read days that have ended, today's readings do not enter until tomorrow, while the night parts (Body Battery, sleep) enter as soon as the night is in. Results are reused for up to 5 minutes. Past days show the value stored for them, and when we change how a number is calculated, past days are scored again (how it works).

Free and Premium#

On the free plan (from 1 November 2026) the Calm tile, the Trends tile, the heart-rate and Oura cards and the energy map are Premium. The free plan keeps today's Body Status with its words (for example "high stress" in a list of things to watch) and the safety alerts, including the high stress banner. Your data keeps arriving. Premium includes the 7-day trial (plans).

Energy pacing mode#

The calculation does not change. In the mode the word is "body load" ("Zátěž těla"), because a pulse can climb on standing up with no worry behind it, and "Day stress" becomes "Body load" (energy pacing).

What you can do#

• Wear the device through the day and at night. Stress needs the day, the night parts need the night.
• Look at the trend, not one afternoon.
• Look for what holds the number up: a short night, a late meal, a hard evening, a busy stretch. Your device reads strain on the body whatever the cause.
• Give yourself a quiet evening and a full night after a heavy day.
• Log "Felt stress" in your check-in when you want to compare how you felt with what the device saw. It does not change the number.

MyBodyAI is a wellness app, not a medical device. Stress Load describes signals from your device. It does not diagnose. If you feel persistently overwhelmed, or unwell, talk to a doctor.

Frequently asked questions#

Why is my Stress Load missing?#

Your device sends no stress index and no Body Battery (Polar, Fitbit, Google Health and Withings send neither), or fewer than two parts exist, or your readings are older than 5 days. A device that gives only a sleep-fragmentation part cannot make the index.

Why does my watch say I was stressed but Stress Load is low?#

Stress Load averages the last 5 days that have ended, so one high afternoon is a small part. It also reads Body Battery, sleep and the trend, and these can be calm. Today does not count until tomorrow.

Why does Recovery show a different stress number?#

Recovery reads the stress index itself, with a 10 % weight and its own rules. Stress Load is a separate index with eight parts. They look at the same readings from two sides.

Why is stress called "Calm" on the Body Status tile?#

Because on the tiles a higher number has to mean a better day. Calm is 100 minus Stress Load, so a Stress Load of 33 reads as a Calm of 67.

Does the stress number say I feel stressed?#

No. Your device works the number out mainly from heart rate and its variability. A pulse that climbs for other reasons, such as on standing up, can read as stress, and a worried mind with a calm pulse may not. That is why the energy pacing mode calls it body load.

Why do I see minutes and not a 0 to 100 number?#

An Oura ring reports minutes in elevated stress, not an index. Minutes have no published scale, so we compare them only with your own days. Stress Load still works from them, with fewer parts.

Can I change the thresholds?#

No. A change to a weight or a threshold changes every day's number, so we change them only in releases, and these entries are checked against the code each time.