The aim of the study is to compare the pharmacokinetics (i.e. the course of the blood concentrations of the administered trial drug) of faster-acting insulin aspart (faster aspart), and the currently marketed formulation of insulin aspart (NovoRapid®) when given as a bolus using an insulin pump in people with type 1 diabetes. The pharmacodynamic response (i.e. the course of the blood sugar lowering effect of the administered trial drug) and the safety and tolerability of faster aspart and NovoRapid® will also be assessed.