If a distance runner with type 1 diabetes measures blood glucose at 5.5 mmol/L before running, what is the best recommendation?

The correct recommendation in this scenario is to consume 30 to 45 grams of carbohydrate prior to starting the exercise. For individuals with type 1 diabetes, exercise can significantly affect blood sugar levels. Typically, exercise increases glucose uptake by muscles, which can lead to a decrease in blood glucose levels, especially if the individual has already maintained a good glucose level prior to exercise, as indicated by the reading of 5.5 mmol/L.

To ensure that the runner maintains sufficient energy levels and to prevent hypoglycemia during their workout, consuming a moderate amount of carbohydrates before exercise helps stabilize blood glucose levels. A range of 30 to 45 grams is often recommended for endurance activities, as this amount can provide adequate fuel and prevent potential drops in blood sugar that may occur once the runner begins to exert themselves.

The other options present lower carbohydrate amounts or suggest taking no measures at all, which would not adequately support the runner's energy needs or prevent hypoglycemic episodes during exercise. Consuming too little carbohydrate may not provide enough of a buffer against the glucose-lowering effects of physical activity, which can be particularly risky for someone with diabetes. Thus, the guidance to consume a higher amount of carbohydrates before exercising is grounded in the need to maintain stable blood glucose