Environmental effects of ambient temperature and relative humidity on insulin pharmacodynamics in adults with type 1 diabetes mellitus

Diabetes Obes Metab. 2019 Mar;21(3):569-574. doi: 10.1111/dom.13555. Epub 2018 Nov 4.


Objective: This study aimed to explore the effects of ambient temperature and relative humidity on insulin pharmacodynamics in adults with type 1 diabetes.

Materials and methods: A three-way, cross-over, randomised study was performed in adults with type 1 diabetes mellitus (n = 10). The pharmacodynamics profile of a single dose of short-acting insulin (insulin lispro) was investigated, using a controlled environmental chamber, under three environmental conditions: (a) temperature: 15°C and humidity: 10%; (b) temperature: 30°C and humidity: 10%; and (c) temperature: 30°C and humidity: 60%. A euglycaemic glucose clamp technique ensured constant blood glucose of 100 mg/dL (5.5 mmol/L). The following pharmacodynamic endpoints were calculated: maximum glucose infusion rate (GIRmax ), time to GIRmax (tGIRmax ), total area under the curve (AUC) for GIR from 0-6 hours (AUCGIR.0-6h ), and partial AUCs (AUCGIR.0-1h , AUCGIR.0-2h and AUCGIR.2-6h ).

Results: Higher temperature (30°C) under 10% fixed humidity conditions resulted in greater GIRmax (P = 0.04) and a later tGIR.max (P = 0.049) compared to lower temperature (15°C). Humidity did not affect any pharmacodynamic parameter. When the combined effects of temperature and humidity were explored, tGIR.max (P = 0.008) occurred earlier, with a lower late insulin pharmacodynamic effect (AUCGIR.2-6h ; P = 0.017) at a temperature of 15°C and humidity of 10% compared to a temperature of 30°C and humidity of 60%.

Conclusions: High ambient temperature resulted in a greater insulin peak effect compared to low ambient temperature, with the contribution of high relative humidity apparent only at high ambient temperature. This suggests that patients with type 1 diabetes mellitus who are entering higher environmental temperatures, with or without high humidity, could experience more hypoglycaemic events.

Keywords: ambient temperature; environmental conditions; insulin pharmacodynamics; relative humidity; type 1 diabetes mellitus.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adolescent
  • Adult
  • Area Under Curve
  • Blood Glucose / drug effects
  • Blood Glucose / metabolism
  • Cross-Over Studies
  • Diabetes Mellitus, Type 1 / drug therapy*
  • Diabetes Mellitus, Type 1 / metabolism*
  • Double-Blind Method
  • Environment*
  • Female
  • Humans
  • Humidity*
  • Hypoglycemic Agents / administration & dosage
  • Hypoglycemic Agents / blood
  • Hypoglycemic Agents / pharmacokinetics
  • Insulin / administration & dosage
  • Insulin / blood
  • Insulin / pharmacokinetics*
  • Insulin Lispro / administration & dosage
  • Insulin Lispro / blood
  • Insulin Lispro / pharmacokinetics
  • Insulin, Long-Acting / administration & dosage
  • Insulin, Long-Acting / blood
  • Insulin, Long-Acting / pharmacokinetics
  • Male
  • Middle Aged
  • Temperature*
  • Young Adult


  • Blood Glucose
  • Hypoglycemic Agents
  • Insulin
  • Insulin Lispro
  • Insulin, Long-Acting