Sustainability has become a significant concern in software systems like websites, driven by their increasing adoption and environmental impact. As website usage grows, so does their energy consumption and carbon footprint, affecting their environmental sustainability. Understanding the relationship be-tween usability and environmental sustainability is essential for designing web sites that meet user needs while minimizing environmental impact. This paper examines this relationship, focusing on popular sports websites due to their substantial internet traffic. We evaluated ten English-language sports web sites for their environmental sustainability and usability using Nielsen's 10 usability heuristics. Our assessment considered factors such as Ecological Accommodation, Content, Operation, Multimedia, and HTTP Requests. The findings reveal a strong negative correlation between usability and sustainability, suggesting that improvements in usability may increase environmental impact and vice versa. This study's insights can inform website de-velopers in creating digital platforms that are both usable and environmentally sustainable.