Why Do You Feel Drowsy on the Highway?

[JasonAnn]

There are three main reasons for fatigue during highway driving: 1. Energy factors: Driving at high speeds requires greater concentration, leading to sustained neural impulses that consume large amounts of energy and oxygen in the brain. Additionally, maintaining driving postures, such as raised hands, pointed toes, and support from shoulders and waist, further increases energy consumption. Prolonged sitting also slows blood circulation, reducing the body's ability to supply energy and oxygen, which can cause drowsiness due to nutrient deprivation in the brain. 2. Oxygen factors: Drivers often keep windows closed on highways. The small, well-sealed space of a car can lead to decreased oxygen levels and increased carbon dioxide concentration. When CO₂ levels exceed 0.2% (normal: 0.04%), it can cause headaches, drowsiness, sluggishness, and difficulty concentrating. 3. Road conditions: Statistics show that drowsiness is far more likely on highways than on regular roads. The enclosed highway environment has fewer distractions, higher speeds, simpler operations, and monotonous visuals. Combined with louder tire and wind noise, the lack of prolonged brain stimulation creates a hypnotic effect on the body.