It can be depending on what you do and what you've been taught as. I never liked doing the treadmill or trying to run for miles on end (not that I can anyway because of certain metals in my legs) plus when you have a form of ADD, its important to understand how your brain keeps firing doing things that keep you going.
Cardio doesn't have to be boring though, there are ways to utilize it so you can keep your stamina up. One of the best ways is through circuit training either with Bodyweight or with Bands like Dopamineo. With bodyweight, you move from one exercise to another and work different muscles instead of doing just one thing the entire time at a steady clip. You can do Hindu Squats or Step Ups by working a number of reps in a row. Some like to do 300-500 Hindu Squats, I'll do 500 or more Step Ups, its a preference. I imagine climbing up a mountain or a bad ass skyscraper when I do them, makes things interesting.
There's also HIIT style training which is a form of cardio but doesn't take up a ton of time. It could Sprinting, Band Work, Bodyweight, using weights, hell it can be on a Rogue Bike, as long as you go hard for a short amount of time and rest two to three times as long. Some workouts are so intense, you go hard but only rest half the amount. I'll do that with the Dopa Band where I work an exercise for 30 seconds but only rest for 15, this amplifies my conditioning where I can keep going and not rest as much.
Most aren't taught how to use cardio to an advantage, its always "you have to do this and its the only way", fuck that lol. If you're going to do cardio, make it worth while and make it interesting. The key thing here is to not go so hard that you can't walk out of it at the end. Always have gas in the tank, there's a difference between breaking a PR and killing yourself in the name of fitness. Workouts should enhance the attributes you're attempting to achieve, if you're a world class athlete, that's a whole different style of training. If you try to do the same or similar style of fitness like Lebron James or Jordan Burroughs or hell even Seth Rollins or John Cena you're in for a rude awakening. Do things that are challenging but not to the point where you need 3-4 days to recover or even longer.
Cardio takes on many forms but it should never be boring otherwise you won't get results you desire. Your mindset has to stay fresh and interested and not so forced it becomes a chore. When I do my Dopa Band circuits, my goal is to keep going until its over but also create a game out of it so I can keep my mind focused. Make your cardio count, don't just go through the motions, anybody can do that, make it work to the degree where you can go and do things that seem crazy to the average person but it keeps you strong and resilient.
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