Slow HTTP requests in a Node.js app can be caused by various factors like slow network connections, blocking code, or database inefficiencies. Start by profiling the request lifecycle using tools like `clinic`, `0x`, or `--inspect` to see where the delay is happening. If network latency is the issue, consider using caching mechanisms like Redis or implementing load balancers to distribute traffic. If blocking code is the issue, ensure your I/O operations (e.g., file reads or database queries) are asynchronous. Database query optimization is another common fix—use indexes, optimize queries, and batch operations where possible. By profiling the performance of your HTTP requests and optimizing the bottlenecks, you can drastically reduce response times and improve your app’s overall performance.