Exercise Time and Duration in PlateLens

“I went for a run” tells you what happened. “I ran for 35 minutes starting at 6:15 PM” tells you where it belongs in the day. PlateLens now carries that second level of context through manual exercise logging: date, start time and duration, suggested by AI and confirmed by you.

A useful exercise record needs a timeline

Calories burned are only one part of a workout record. The same activity can mean something different in the sequence of a day depending on whether it happened before breakfast, during a lunch break or late in the evening. Duration matters too: it drives the calorie estimate and turns a single clock value into a real start–end range.

PlateLens stores the time the exercise actually started separately from the time the entry was saved. If you log a morning workout after dinner, the Diary can keep the morning start instead of silently treating the logging moment as the workout.

Describe the workout; review the facts

The exercise flow still starts with natural language. Type or say “45 minutes of moderate cycling, started at 7:20”, and PlateLens interprets the activity, duration and precise time together. It uses that duration for the calorie estimate and shows any assumptions it had to make.

AI suggestions do not become hidden facts. Date, start time, duration, activity type and calories stay visible before you save. An assumed duration is identified as an estimate, and every field can be corrected. The fastest flow remains fast without making the record less trustworthy.

“Finished now” is a visible convenience

Many people remember how long they exercised but not the exact minute they started. On Today, when the description has a duration and no time wording, PlateLens offers Finished now. It freezes the estimate gesture as the finish and subtracts the duration. A 30-minute session captured at 7:10 PM becomes 6:40–7:10 PM. Vague context such as “this morning” is kept honest and remains without a precise start.

That choice is shown on the review screen. Change the duration and the start moves to preserve the frozen finish; choose a different start and the entry becomes your explicit time instead. Convenience never needs to masquerade as certainty.

Past Diary days stay honest

A historical Diary entry follows a different rule. If you open a past date and write “30-minute walk” without a clock time, PlateLens keeps the selected date and the duration but leaves the start unset. It does not pretend the walk happened at the time you are typing today.

If the description includes a precise start, PlateLens can propose it on the selected Diary date. Otherwise, you can add the real time yourself or keep the exercise as a day-level record.

One timing model across every PlateLens surface

Built for real time zones

An exercise start is stored as a real instant plus the IANA time zone that assigns it to its Diary date. A workout at 6:00 PM in New York remains on that New York day after you travel. Daylight-saving gaps are rejected instead of shifted, and a repeated hour can be disambiguated when necessary.

The same timing remains editable. Moving a timed exercise to another Diary date preserves its local clock time when that time exists on the destination day.

Better timing, without turning PlateLens into a form

The product goal is not to make everyone complete three extra fields before logging movement. Natural language handles the first pass. Today has a transparent default. Historical days avoid a false one. The review screen appears only where the information can be checked and changed.

Manual exercise still contributes to activity-adjusted targets, and it remains separate from movement imported from a phone or wearable. Timing makes the manual record clearer; it does not automatically deduplicate two copies of the same workout.