Why Do I Feel Sleepy as Soon as I Start Driving?

[MacWyatt]

The reasons for feeling sleepy as soon as you start driving are as follows: 1. Air recirculation mode: Prolonged driving with the air recirculation on prevents air circulation inside the car, leading to a lack of fresh air inflow. This reduces oxygen levels in the vehicle, causing brain hypoxia. Insufficient oxygen supply to the brain results in a drowsy feeling. 2. Monotony: Maintaining the same sitting posture throughout a long and tedious journey significantly reduces the driver's burden. Over time, this leads to visual fatigue. Prolonged exposure to a state with minimal stimulation can inhibit and slow down brain activity, causing attention to wander and reactions to become sluggish. 3. Overeating at lunch: More blood is required in the stomach to aid digestion, and the digestive activities of the intestines suppress brain activity. This reduces blood supply to the brain, leading to a drowsy sensation.