FortiorRecovery
Sleep and strength training
Many lifters wonder how their sleep lines up with their training. Fortior puts your sleep next to your lifting and cardio so you can see the pattern in your own data, without assuming what causes what.
Why look at sleep next to training
Sleep is one of the first things lifters check when a session feels off, and one of the easiest to over-read. One short night followed by a poor session proves little, because stress, food and a hard week can explain both. Patterns across many nights say much more. That is why Fortior shows sleep as a history and compares it with your lifts only once there is enough data.
Public health guidance for adults commonly cites at least seven hours a night, and individual needs vary.
What Fortior shows about sleep
- Sleep Summary. Average sleep, your latest night, how many nights are logged in the range, and how much your duration varies from night to night. When your source provides them, it adds average deep and REM minutes, a sleep score and the provider's recovery score. Readings for the same night from different sources are averaged, and the sources are named.
- Sleep Details. Charts for duration in hours, stages in minutes and HRV in milliseconds. On longer ranges the nightly points become 3-day and then weekly averages so the chart stays readable.
- Sleep and Training. A scatter chart that looks at sleep and training in both directions.
Reading sleep against training
| Direction | Each dot is | What it asks |
|---|---|---|
| Sleep to next day | Hours slept, against how your lifts went the next day compared with your own usual | Do longer nights tend to come before stronger-than-usual lifts? |
| Training to that night | A day's training load, against the hours you slept that night | Are your hardest days followed by shorter nights? |
A worked example
For the first direction, your usual is the median of your last two to five sessions on that lift within 90 days, using the estimated one-rep max from sets of 12 reps or fewer. Say your last four bench sessions had best estimated maxes of 100, 102, 101 and 103 kg. The median is (101 + 102) ÷ 2 = 101.5 kg. A best of 99 kg the day after a short night is (99 ÷ 101.5 − 1) × 100 = −2.5%. Fortior averages that across the lifts you trained that day, and 0% means your usual.
The card waits for at least five matching pairs before it draws a conclusion, and tells you how many it still needs. It then reports a correlation (Pearson r) and puts it in words, such as little to no link, a weak pattern or a moderate one. A correlation describes how two sets of numbers move together. It doesn't show that one caused the other, and Fortior labels the result observational and specific to you.
Where the sleep data comes from
Fortior reads sleep from Apple Health, WHOOP and Oura. From Apple Health it counts time asleep (core, REM and deep) rather than time in bed. If several apps write sleep for the same night, it uses the source with the most time asleep instead of adding them together.
Devices detect stages in different ways, so compare stage minutes within one device and not across devices. Provider sleep and recovery scores appear as the provider recorded them and stay separate from Fortior's readiness.
Reading the patterns honestly
- Missing nights weaken any pattern. A watch left on the charger leaves a gap, not a short night.
- Other things move both sleep and training. Stress, travel, a late session and caffeine can all show up on both sides of the chart. A pattern is not a cause.
- Look at consistency as well as totals. The duration variation in the summary shows how much your nights differ from one another.
- Use it to ask better questions. For example, whether your hardest evenings are followed by shorter nights, rather than to chase a single number.
In the app: open Progress and choose Sleep. If no nights appear, connect Apple Health, WHOOP or Oura in Settings under Integrations. Some views are part of Fortior Premium. Plans and prices appear in the app.
Sleep patterns in Fortior are observational and specific to you. They are educational, not medical advice, and they don't show that sleep causes any change in your training. Talk to a healthcare professional about sleep concerns.