Since we have began keeping records in the late 1800s, there have been 26 confirmed deaths from cougar attacks in the US. Which is not to say one shouldn't be smart and aware of the situational risks of any activity, but calling it "dangerous" on that basis seems a bit extreme. In the past 30 years, despite a steady increase in hiking and trail-running, there have been 62 attacks total.

It is estimated that 50 million Americans go hiking each year, and of them 25,000 will die out on the trail. Hiking has some inherent risks. Cougar attacks should only be slightly higher than "swarmed to death by killer bees" on the list of reasons you don't go hiking or trail running.

Have ran 1000s of miles in cougar country without ever even seeing one ... Way more afraid, and more likely to be hit by a motorist on the road or struck by lightning. Not saying ignore the dangers of wildlife, but its very unlikely.