Cardio.
Research has shown that Yoga or some types of Yoga exercises are bad for health. According to recent research, Yoga can cause joint injury. Telegraph reported in June 2017:
The 5,000 year-old Indian discipline is said to boost physical and mental wellbeing, ...
However, in a recent study yoga caused musculoskeletal pain - mostly in the arms - in more than one in ten participants.
Professor Evangelos Pappas, of Sydney University, the study's lead researcher said: "Yoga may be a bit more dangerous than previously thought.
"Our study found the incidence of pain caused by yoga is more than 10 percent per year - which is comparable to the rate of all sports injuries combined among the physically active population.
"However people consider it to be a very safe activity. This injury rate is up to 10 times higher than has previously been reported."
https://www.telegraph.co.uk/news/2017/06/28/yogamore-dangerous-previously-thought-scientists-say/
Cardio on the other hand do not have these risks unless you are pushing against your limit. Our hearts are made of muscles. Doing Cardio exercises improve our heart and regular physical activity. Cardio is bad only if you are doing it to the extreme:
At extremes, cardiovascular exercise can contribute to cardiac plaque, irregular heartbeats and heart disease.