Table 1 Summary of included trials investigating the threshold of AVP release and thirst stimulation in response to increasing plasma osmolality
From: The sensitivity of the human thirst response to changes in plasma osmolality: a systematic review
Author (year) (citation) | Age mean | Subject condition | Sample size | Dehydration mechanism | Thirst threshold mean (±SD) mOsm/kg | Relevant findings |
|---|---|---|---|---|---|---|
(Thompson, Bland et al. 1986) | 24.3 | Healthy | 10 | 5% NaCl @ 0.06 ml/kg/min for 2 h | 281.1 ± 3.2 | High individual repeatability of threshold results. Lower threshold found, stimulating thirst before significant dehydration occurs. |
(Phillips, Bretherton et al. 1991) | 25 69.8 | Healthy Young Healthy Elderly | 7 7 | 5% NaCl @ 0.06 ml/kg/min for 2 h | 261.0 ± 18.5 276.0 ± 13.2 | Elderly show reduced thirst |
(Davies, O'Neill et al. 1995) | 26.8 70.5 | Healthy Young Healthy Elderly | 10 10 | 5% NaCl @ 0.1 ml/kg/min for 2 h | 287.5 ± 12.6 292.4 ± 8.5 | Thirst threshold is not elevated in healthy elderly, but inter-subject variation is greater. Linear response of thirst to pOsm identified. |
(Thompson and Baylis 1987) | 29.2 28.6 | Healthy Controls Diabetes insipidus | 15 14 | 5% NaCl @ 0.06 ml/kg/min for 2 h | 286.3 ± 3.9 286.3 ± 3.9 | Diabetes insipidus does not alter thirst or AVP response to pOsm |
(Thompson, Davis et al. 1988) | 30 29.1 | Healthy Controls Type 1 Diabetes | 7 7 | 5% NaCl @ 0.1 ml/kg/min for 2 h vs: Glucose raised from 4 to 20 mmol/l over 2 h | 284.7 ± 1.6 287.0 ± 6.9 | Oral fluid intake rapidly abolished thirst independent of pOsm. Type 1 Diabetes does not alter thirst and AVP response. |
(Thompson, Edwards et al. 1991) | 29.6 | Healthy controls | 7 | 5% NaCl @ 0.05 ml/kg/min for 2 h | 286.5 ± 3.2 | No significant difference between thirst and AVP thresholds. |
(Thompson, Selby et al. 1991) | 34.1 | Healthy | 16 | 5% NaCl @ 0.06 ml/kg/min for 2 h | 286.3 ± 4.2 | Very high 6 month repeatability of AVP and thirst threshold seen within individuals |
(Argent, Burrell et al. 1991) | 41.1 41.4 | Healthy Chronic Kidney Disease | 7 8 | 5% NaCl @ 0.06 ml/kg/min for 2 h | 279.4 ± 5.8 281.8 ± 6.8 | Threshold of AVP & Thirst are very close in both subject groups |
(Phillips, Butler et al. 1994) | 41.5 | Healthy | 8 | 5% NaCl @ 0.06 ml/kg/min for 2 h vs. 20% Mannitol @ 0.07 ml/kg/min for 2 h | 291.0 ± 5.8 | 5% saline is a more powerful osmotic stimulant than mannitol. The threshold for mannitol is similar but the slope lower |
(Martinez-Vea, Garcia et al. 1992) | 43.1 55.0 | Healthy Controls Chronic Kidney Disease | 6 5 | 5% NaCl @ 0.06 ml/kg/min for 2 h | 289.8 ± 8.3 288.9 ± 19.0 | High degree of sensitivity and repeatability in individual responses of thirst to osmolality. Thirst unaffected by chronic kidney disease, but dialysis causes a variation. |
(Smith, Moore et al. 2004) | 51.8 | Healthy Controls | 8 | 5% NaCl @ 0.05 ml/kg/min for 2 h | 285.9 ± 2.8 | Oral fluid intake abolishes osmotically stimulated thirst. Some individuals can lack thirst response. |
(McKenna, Morris et al. 1999) | 69.8 70.5 | Healthy Controls Type 2 Diabetes | 7 7 | 8 h water deprivation | 285.5 ± 2.5 283.9 ± 2.0 | Osmoregulation of thirst and AVP are normal in Type 2 Diabetes. |