This last 10 pounds has gone quickly for me, thanks to a change in how I approach my cardio. First, I now call it cardio, as opposed to my daily walk! (This is a big step for me; until Dukan I loathed all forms of exercise, and would break out in hives at the thought of “cardio”.) Second, I came across Rusty Moore’s book – Visual Impact For Women – and actually read it. Most of it. I don’t pretend to understand even half of it. Just enough to understand that if we add “spurts” to our walks then we burn a lot more calories and the weight “gets released” faster! This from Rusty Moore’s blog –
Intervals Allow Hard Work With Lower Blood Lactate
Let’s discuss why intervals are effective in the first place compared to just training hard at a steady rate. Intervals allow you to spend a greater amount of time doing intense exercise at lower blood lactate levels than simply “running hard”. The active rest is what prevents lactic acid buildup in the muscles. HIIT cardio allows you to spend more total time at high-intensity levels without feeling it as much as simply training hard non-stop.
Less Pain & Fatigue With the Same Total Time at High Levels
Let’s say that you do intervals of 30 seconds walking and 30 seconds running. Your average running speed is 10.5 miles per hour and you do intervals for 20 minutes. That is 10 total minutes of running at 10.5 miles per hour. If you run at that pace for 10 minutes straight, you would be gasping for air as well as feel a burn in your legs after a minute or two. Alternating running with walking is what allows you to get this same amount of higher intensity exercise in without the pain and fatigue caused by lactic acid buildup. The same amount of work with less of a perceived effort.
The shorter intervals had a 90% greater oxygen uptake than the longer intervals. This created a larger oxygen debt. Why is oxygen debt important? When you train at an intense level, like sprinting, your body can’t supply oxygen at a fast enough rate to fuel the muscles. After the intense effort is completed, your body has to basically repay that “borrowed energy”…it owes oxygen to get those muscles back to their normal state. The more energy your body borrowed during an intense effort the more oxygen it owes…this is called Oxygen Debt. The larger the oxygen debt created by your workout the longer it will take to repay it…with the benefit of more calories burned for a longer period of time after you are done exercising.
Okay, so what you s’posed to do? I dunno about you, but I’m still a big girl. And while I had lost 30 pounds when I read Rusty’s book, there’s no way I’m jogging without very serious knee pain. But what I have found is that if I begin my walk slowly, work up to steady and then at the 10 minute mark, start doing 30 seconds as fast as I can, followed by 1.5 minutes of steady (recovery) pace and then hit the speed again…and if I can do that for 10 minutes, then finish up with the regular 10 minutes steady and a cool down, I’m much more tired. I’m perspiring up a storm and the next day there’s good news on the scale!