Figure 1. Glucose and insulin trajectories during the experimental period. Concentrations (every 10 minutes) of glucose and insulin in blood serum over a 90- minute period, comprising measurements before and after intranasal application of insulin (40IU insulin Actrapid, blue line) or placebo (saline, red dotted line) using ViaNase nasal atomizer. Blue arrow indicates timing of intranasal administration of insulin or placebo. Data is presented as mean with standard error in (A) glucose trajectory in young and (B) insulin trajectory in young (C) glucose trajectory in older and (D) insulin trajectory in older adults.