A free, guided lying-down practice of ten to thirty minutes, needing no equipment or physical capacity. The firmest findings are lower blood pressure and lower self-reported anxiety and stress, with sleep close behind. It easily beats doing nothing but often fails to beat another structured relaxation technique. Harms are mild, greatest where unresolved trauma is present. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Home blood pressure | 110–120 / 70–75 mm Hg | The best-supported measurable target of the practice |
| Resting heart rate | 50–65 beats per minute | Tracks the shift toward the rest-and-digest side of the nervous system |
| Heart rate variability | No established target; rising seven-day rolling average against the individual's own 30-day baseline | Direct index of vagal nerve activity, the mechanism behind the blood pressure effect |
| Pittsburgh Sleep Quality Index | 5 or below | Validated sleep-quality questionnaire used in most trials |
| Insomnia Severity Index | 7 or below | The scale on which the clearest randomised sleep benefit was measured |
| Morning salivary cortisol | 0.3–0.7 µg/dL at 30 minutes after waking | Captures the stress-hormone output the practice reduces |
| High-sensitivity C-reactive protein | Below 1.0 mg/L | General inflammatory load, a slow-moving background marker |
| Glycated haemoglobin | 4.8–5.3% | Average blood sugar, relevant given the glucose finding |
| Fasting glucose | 75–86 mg/dL | Detects the glucose shift seen in the diabetes trial |
| Thyroid-stimulating hormone | 0.5–2.0 mIU/L | Only relevant where menstrual irregularity is the reason for practising |
Cadence: Home blood pressure weekly for the first eight weeks, then monthly. Sleep and anxiety questionnaires at four weeks, twelve weeks, then every six months. Blood tests at three months, then every six to twelve months.