Weekly dose helper
Minutes per session × sessions per week → weekly total; see where it falls against Howell 2021’s published volume lines.
Read this first
Not medical advice. Educational use only.
- This helper adds up weekly minutes — it does not set intensity. Pair it with the HR helper or a symptom cap for the “how hard” question.
- 100 min/week is what Howell 2021 actually prescribed (20 min × 5 d/wk). It is a documented prescription line, not a proven minimum dose.
- 160 min/week is a post hoc, observational cutoff from the same paper — it discriminated symptom-free vs symptomatic adolescents at one month. It is not a second prescription target.
- 150 min/week is from a different paper, different outcome (Howell & Wingerson 2024, sleep quality) — shown for reference only. Do not treat it as interchangeable with the 160-minute symptom line.
Why this exists
The installment Twenty minutes from where? argues that session length is the wrong unit — the literature’s actual signal is in the weekly total, not any single session’s stopwatch reading. This page does the arithmetic so a family or clinician can see where their week actually lands.
Related reading: Disagreement 2 — prescribed vs. observed · Howell 2021 volume analysis, PMID 33856860
Weekly total —
Vs. Howell 100 min/wk (prescribed) —
Vs. Howell 160 min/wk (symptom ROC, observational) —
Dashed line at 150 min/wk = Howell & Wingerson 2024 sleep-outcome band, a different paper and a different outcome — reference only, not a second symptom threshold.
Boundaries
| Topic | What this tool does / does not do |
|---|---|
| Intensity | Not covered here — pair with the HR helper or a symptom cap. |
| 100 vs 160 | Two different constructs from the same paper (prescribed line vs. post hoc observational cutoff). This tool labels them separately on purpose — see the installment’s Disagreement 2. |
| 150 min/wk | A different paper, a different outcome (sleep, not symptoms). Shown for reference, not merged with the 160-minute line. |
| Session-length guilt | Uneven session lengths that still hit the weekly total are not a protocol failure — see the installment’s Pattern A. |