Yes, cardio can potentially cause muscle loss, especially when it is the sole form of exercise combined with a calorie-restricted diet. Cardio, such as steady-state cardio, primarily teaches your body become more efficient and build, rather than building muscle When done in isolation, it lead to a slowdown in and significant muscle loss as the body adapts to become at cardio.
However, there is a form of cardio called high-intensity interval training (HIIT) that, when done properly, can have a muscle-preserving effect. HIIT combines some of the benefits of resistance training with cardiovascular exercise. Studies have shown that the fat loss percentage is higher in HIIT compared to steady-state cardio, with minimal muscle loss.
It's important to note that incorporating resistance training into your routine can help negate the muscle loss effects of cardio. The goal should be to build muscle and burn body fat simultaneously, and this can be achieved by combining resistance training with the appropriate form of cardio.