Urine Specific Gravity by age and sex
Each bar runs from the 5th to the 95th percentile, the darker part from the 25th to the 75th, and the tick is the median. Not a reference range or a target.
The percentiles as a table
| Sex | Age | 5th | 25th | Median | 75th | 95th | n | Cycle / source |
|---|---|---|---|---|---|---|---|---|
| All | 20-39 | 1.01 | 1.01 | 1.02 | 1.02 | 1.03 | 1,409 | NHANES 2007-2008 |
| All | 40-59 | 1.00 | 1.01 | 1.02 | 1.02 | 1.03 | 1,527 | NHANES 2007-2008 |
| All | 60+ | 1.00 | 1.01 | 1.01 | 1.02 | 1.02 | 1,659 | NHANES 2007-2008 |
| All | all | 1.00 | 1.01 | 1.02 | 1.02 | 1.03 | 4,595 | NHANES 2007-2008 |
| Men | 20-39 | 1.01 | 1.01 | 1.02 | 1.02 | 1.03 | 718 | NHANES 2007-2008 |
| Men | 40-59 | 1.01 | 1.01 | 1.02 | 1.02 | 1.03 | 742 | NHANES 2007-2008 |
| Men | 60+ | 1.01 | 1.01 | 1.02 | 1.02 | 1.03 | 839 | NHANES 2007-2008 |
| Men | all | 1.01 | 1.01 | 1.02 | 1.02 | 1.03 | 2,299 | NHANES 2007-2008 |
| Women | 20-39 | 1.00 | 1.01 | 1.02 | 1.02 | 1.03 | 691 | NHANES 2007-2008 |
| Women | 40-59 | 1.00 | 1.01 | 1.01 | 1.02 | 1.03 | 785 | NHANES 2007-2008 |
| Women | 60+ | 1.00 | 1.01 | 1.01 | 1.02 | 1.02 | 820 | NHANES 2007-2008 |
| Women | all | 1.00 | 1.01 | 1.01 | 1.02 | 1.03 | 2,296 | NHANES 2007-2008 |
What studies found when this marker was changed
They describe what happened in those study groups, not a recommendation. See all catalogued interventions.
Measured changes in Urine Specific Gravity, study by study
4 effects with a numeric size, each from one study arm: the dot is the reported change, the line its 95% interval where one was given. Study results in the groups studied, not predictions for a person.
| Type | Intervention | Reported effect | Evidence | Source |
|---|---|---|---|---|
| diet | Consistent daily fluid hydration (2.5-3.5 L/day water intake) | High drinkers (2–4 litres/d) had 24h urine specific gravity median 1·010 vs 1·023 in low drinkers (≤ 1·2 litres/d) | cross-sectional | Perrier E, et al. Hydration biomarkers in free-living adults with different… |
| exercise | Fluid replacement (150% of sweat losses) after heavy endurance exercise | Replacing 150% vs 75% of sweat losses after a run lowered next-morning USG (1.014 vs 1.026) | non-randomised trial | Davis BA, et al. Hydration kinetics and 10-km outdoor running performance… |
| lifestyle | Structured hydration education increasing daily water intake | Raised daily water intake (749.8 vs 572.9 mL) and improved urine specific gravity vs control (p < .001) | RCT | Çimen A, et al. Health Belief Model-Based Education to Improve Water Intake and… |
| lifestyle | Consuming the recommended 2.5 L of fluid per 24 h (euhydration day) versus usual ad libitum intake in healthy young women | USG went from 1.014 at baseline to 1.010 by 5 PM on the euhydration day (vs 1.011 on the control day and 1.021 on the dehydration day; P<0.05) | RCT | Stachenfeld NS, et al. Physiol Behav. 2018. Water intake reverses dehydration… |
| pharmacologic | Tolvaptan (vasopressin V2 antagonist) titrated by body weight and tolerability in children and adolescents aged 4-17 with autosomal dominant polycystic kidney disease | Spot urine specific gravity fell by 0.009 (LS mean, SEM 0.001) at week 1 vs 0.002 with placebo (P<0.001) | RCT | Mekahli D, et al. Clin J Am Soc Nephrol. 2023. Tolvaptan for Children and… |
Things that worsen it
| Type | Condition or exposure | Reported effect | Evidence | Source |
|---|---|---|---|---|
| clinical | Advanced chronic kidney disease / isosthenuria | Failing kidney gradually develops hyposthenuria and even isosthenuria (fixed urine concentration; effect size not reported) | review | Kovesdy CP. Significance of hypo- and hypernatremia in chronic kidney disease… |
| environmental | Heat-induced dehydration (passive heat exposure with body water loss) | 5-h heat exposure (36 °C) with 1-2% body mass loss significantly increased USG vs baseline (effect size not reported) | RCT | Muñoz CX, et al. Assessment of hydration biomarkers including salivary… |
| lifestyle | Minimising fluid intake over a day of normal activity in healthy young women (dehydration session) | USG rose from 1.015 at baseline to 1.021 by 5 PM on the dehydration day (vs 1.011 on the control day; P<0.05) | RCT | Stachenfeld NS, et al. Physiol Behav. 2018. Water intake reverses dehydration… |
Sources
- See the catalogue entry in the research dashboard.
Related markers: Proteinuria (Dipstick) · Urinary Creatinine Concentration · Urinary Flow Rate · Urine Albumin-to-Creatinine Ratio (uACR)