Training load is Titan's running total of the cardio work you have done, built from the minutes you spend in each heart rate zone during workouts. Titan keeps two versions. Short-term load tracks about the last week and stands for fatigue. Long-term load tracks about the last six weeks and stands for fitness. The load ratio divides one by the other and shows when your recent training has outrun what you are used to. Apple Watch keeps its own training load, built from workout effort ratings, covered in Apple Watch training load compared with Titan.
01Daily load
Each day Titan adds up your workout minutes in each heart rate zone and weights every minute by its zone number. A minute in Zone 1 counts 1. A minute in Zone 5 counts 5. A workout with 30 minutes in Zone 2 and 10 minutes in Zone 4 scores 60 plus 40, a daily load of 100. A day with no workout scores 0. The same daily number drives your Exertion score.
A workout with no heart rate data still counts. Titan multiplies its duration in minutes by a factor for the activity type.
| Activity type | Load per minute |
|---|---|
| Endurance, such as running or cycling | 1.0 |
| Mixed intensity | 0.95 |
| Strength | 0.9 |
| Mobility | 0.65 |
| Other, with distance | 0.95 |
| Other, without distance | 0.8 |
| Other, renamed as sauna or steam | 0.5 |
02Short-term and long-term load
Both lines are exponentially weighted averages of your daily load. Short-term load uses a 7-day time constant. Each day it moves about 13 percent of the way from yesterday's value toward today's load. Long-term load uses a 42-day time constant and moves about 2.4 percent per day. Days without data count as rest days with a load of 0.
Titan starts the calculation 84 days before the first day on the chart, so the left edge already reflects the training that came before it.
03Balance and ratio
Balance is long-term load minus short-term load. A positive balance means you have trained less than usual lately. A negative balance means recent training sits above your long-term level. On the chart, balance is the gap between the two lines.
The load ratio is short-term load divided by long-term load, shown to two decimals. Titan skips the ratio on any day when long-term load is 0.
Say you have trained at a steady 150 per day. A week at 300 per day lifts short-term load to about 245 and long-term load to about 173, a ratio of 1.41. A full week off instead drops short-term load to about 55 and long-term load to about 127, a ratio of 0.43.
04Ratio zones
Titan sorts the ratio into four zones and names the zone next to the ratio.
| Zone | Load ratio | What it means |
|---|---|---|
| Low | Below 0.8 | Your recent training sits well below your usual load |
| Optimal | 0.8 up to 1.4 | Your recent training is close to what you are used to |
| High | 1.4 up to 1.6 | Your recent training has climbed above your usual load |
| Risk | 1.6 and above | Your recent training is far above your usual load |
The zone name is green in Optimal and red in the other three. A Low ratio is expected when you cut training on purpose before a race, which is what the Tapering training goal describes.
05Where to read it
The Trends tile on Today shows your latest ratio, such as Training Load Ratio 1.12. An arrow appears when the ratio moved more than 0.01 from the previous value. The sparkline plots your last 7 days of daily load.
Tap the tile to open Trends. Training load is the first chart. The period menu at the top offers 30 Days, 60 Days, 6 Months, and Year, and Trends opens on Year. The chart draws long-term and short-term load as two lines. Tap or hold the chart to read both values and the load ratio for any day.
Under the chart, a line such as "Ratio 1.12 · Optimal" gives the latest ratio in the period and its zone. It reads "No data" when no day in the period has a ratio.
On Apple Watch, the Trends row in the Titan app shows your latest load ratio, and the Trends screen labels it Training load ratio.
06The Typical band
A shaded band labeled Typical marks the middle 50 percent of your daily long-term loads across the selected period, using interpolated quartiles. It needs at least 28 daily values that cover at least 80 percent of the period. On 60 Days that means 48 of the 60 days. Until then, Trends shows "Range needs 28 days of training load" under the chart. The band describes your own history. It is not a training target.
07Training load focus
Below the chart, Training load focus splits your zone-weighted load for the selected period into three rows.
| Row | Zones |
|---|---|
| Low aerobic | Zones 1 and 2 |
| High aerobic | Zone 3 |
| Anaerobic | Zones 4 and 5 |
Each row shows the group's load and its share of the total. When the period has no zone time, the section reads "No zone minutes in this period". Workouts without heart rate data have no zone time, so they add to your daily load and stay out of the focus split.
If past load looks wrong after you fix workout data in Apple Health, Clear Exertion Cache recalculates Exertion, Training Load and Sleep Debt history. See resync and history.
