My favorite muscle building cardio workout is to get up and go for a half hour walk before breakfast. I usually do this about four or five days per week and I do it for a few reasons. First of all, I do it for cardiovascular health. Too many people simply lift weights and ignore all the other components of fitness. I do it first thing in the morning because I know that if I start my day by checking email or doing some other sort of work the likelihood of me walking later in the day is very low. I get up and get it done immediately so it's out of the way. Also, it increases my appetite and seems to stoke my metabolism for the day. This allows me to eat more with less likelihood of adding bodyfat. It also helps wake me up, clears my head, gives me time to think and packs my lungs full of fresh air, which is incredibly important during the winter when everyone around you is sick as a dog 24/7. I believe this is one of the many things I do that keeps me healthy.
There are a lot of hills in my neighborhood so it's pretty easy to get the heart pumping. If you don't live in a hilly area and are in decent shape you will probably need to wear a weighted vest or drag a sled. If you opt to wear a weight vest, which I do some mornings, depending on the route I take, be sure that you don't get overzealous and add too much weight too soon. You have to remember that if you are walking for thirty minutes you are going to be taking a lot of steps. Each of those steps will add up to stress on your ankles, knees, hips and spine. So start with no more than ten pounds on the vest and try to keep the majority of the weight in the back instead of split evenly. Slowly, over time you can add a few pounds per week. Personally, I wouldn't recommend ever adding more than 30 or 40 pounds to the vest if you are going to be walking for a half hour.
It should be noted that the more muscle mass you have the more calories you will burn when you walk. In fact, legendary bodybuilder and multiple time Mr. Olympia winner, Dorian Yates used walking as his only muscle building cardio workout to get him down to single digit bodyfat percentages before contests. That was because he carried nearly 300 pounds of muscle on his six foot frame. If you aren't quite as jacked up as the Diesel, walking alone will probably never get you shredded. You are going to have to build more muscle or you are going to need some sprints and more intense methods to get the job done.
If you do decide to start walking on a regular basis for your muscle building cardio, please remember that one of the major benefits is getting outside and breathing heavy in the fresh air. Whatever you do, DO NOT walk on a treadmill. This is by far the most ridiculous invention in the history of the planet. There are roads, hills, sidewalks, woods, mountains and fields everywhere across the world. And there is no way that you can honestly tell me that you can't find somewhere else to walk but on a treadmill.
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