Night-time blood pressure
This is a measurement and a rhythm, not a level. Healthy pressure falls roughly 10-20% overnight. When it does not — the “non-dipper” pattern — the daytime reading can look ordinary while the vessels, kidneys and heart never get their night off. This matters because impaired nocturnal fall is an independent predictor of target-organ damage and cardiovascular events, and a clinic cuff cannot see it. Only ambulatory monitoring can. The honest limit: the clearest evidence here is a subgroup finding. Controlled-release melatonin lowered nocturnal systolic pressure 6.1 mmHg while fast-release melatonin did nothing at all (-0.3 mmHg, p=0.92). Same molecule. The release profile decided whether it worked. A 2024 meta-analysis found no effect because it pooled all formulations together — which is the error the subgroup exposed.
In depth
Nocturnal blood pressure and the dipping pattern — how far pressure falls while you sleep.
What drives it
Body clock increases it.
The circadian clock drives the night-time sympathetic withdrawal that produces normal nocturnal blood-pressure dipping. PMID 17360665
Sleep hormone reduces it.
Nocturnal melatonin release lowers sympathetic outflow and supports the night-time fall in blood pressure. doi 10.2147/vhrm.s24603
What it drives
It increases Blood pressure.
Individual-patient meta-analysis of 3,468 hypertensive patients from 4 prospective European studies, 23,164 patient-years. Entered simultaneously, night-time blood pressure predicted all outcomes — all-cause and cardiovascular mortality, coronary heart disease and stroke — while daytime pressure “did not add prognostic precision to nighttime pressure”. The systolic night-day ratio predicted all outcomes. hypertensive patients without major cardiovascular disease at baseline; 61% were on antihypertensive treatment; European cohorts only. Corroborated in the Ohasama general population (PMID 15596571): “only nighttime blood pressure significantly predicted the cardiovascular mortality risk”. PMID 15596571
It reduces Heart & blood pressure.
Seven cohort studies, 10,438 untreated hypertensives: dippers at baseline (n=7,081) had a significantly lower risk of cardiovascular events and total mortality than non-dippers (n=3,357) — RR 0.67 (95% CI 0.49-0.92) for CVEs and RR 0.71 (95% CI 0.59-0.86) for mortality. MEDLINE, Embase, Cochrane Library and gray literature searched to March 2020; untreated hypertensives only, follow-up >6 months, Newcastle-Ottawa risk of bias; heterogeneity moderate (I2 = 50%). PMID 33164307 /. PMID 33164307 · PMC8030020
Blends that modulate it
Each blend page names this pathway and carries the study behind its claim.
See it on the map
Open the causal map to follow this pathway upstream and downstream, arrow by arrow, each with its study.