From my experience with cats, their reactions to humming can vary widely depending on their personality and prior exposure to sounds. Some cats seem curious and even calm down when they hear a steady, gentle hum, while others might get startled or anxious due to the unfamiliar noise. I noticed that humming creates low-frequency vibrations that can be soothing for humans, especially when trying to clear sinuses, as the vibration helps loosen mucus and relieve pressure. However, cats have a much more sensitive hearing range than humans, so what sounds relaxing to us might be uncomfortable or even scary for them. If your cat appears frightened by your humming, try lowering the volume or changing the pitch. Sometimes cats react not just to the sound but to sudden changes in tone or volume. Observing their body language—ears flattening, tail twitching, or attempts to hide—can give clues about their comfort level. Humming is also an interesting natural remedy used by many to alleviate sinus problems, as the vibrations encourage airflow and sinus drainage. While this benefits humans, it's important to remember that your cat's sensory world is different, and what helps you might not have the same effect on them. In summary, if you want to enjoy humming without upsetting your cat, start softly and watch for signs of distress. Over time, your cat may get used to it, or you might find that gentle humming creates a calming environment for both of you.