Most under desk treadmills are designed to be quiet, with noise levels similar to a whisper or light conversation. However, noise can vary depending on the model and speed settings. Look for treadmills with noise-reducing features for a quieter work environment.Most under desk treadmills are designed to be quiet, with noise levels similar to a whisper or light conversation. However, noise can vary depending on the model and speed settings. Look for treadmills with noise-reducing features for a quieter work environment.