What is a significant effect of large accumulations of carbon monoxide in the human body?

Large accumulations of carbon monoxide in the human body primarily lead to a loss of muscular power. This occurs because carbon monoxide binds to hemoglobin in the red blood cells more effectively than oxygen, reducing the amount of oxygen transported throughout the body. As muscles rely on oxygen to generate energy and sustain activity, a decrease in oxygen availability can result in weakness and reduced physical performance. This is particularly critical during situations that require exertion or when engaging in physical activities.

In contrast, other options suggesting an increase in energy, improved cognitive function, or heightened alertness do not accurately reflect the physiological effects of carbon monoxide toxicity. Instead of enhancing energy or cognitive abilities, the presence of carbon monoxide creates a hypoxic condition that significantly impairs physical and mental performance, demonstrating the dangers associated with exposure to this gas.