Many people believe muscle is heavier than fat, but this is an urban myth!
Muscle is actually leaner than fat, so put simply, while muscle is the equal of fat in weight, it doesn't take up as much room. So expect to not see a huge difference in the scales when you first start these demanding workouts, as you begin to turn fat into muscle. That's why it's wise to rely more on a tape measure than the scales and then you can see the inches coming off!
BLOWING THE FAT-BURNING ZONE MYTH OUT THE WATER!
EXERCISING at a comfortable pace is good for fat loss as it enables us to work in our Fat-Burning Zone. i.e. using around 65% of our maximum effort. That's true.
BUT that's because the body uses more fat than glycogen while exercising at a relatively comfortable pace. The problem arises as the body becomes more endurance focussed. After a while, the body plateaus (this is particularly true for women) so, at the very least, a change of routine is essential. But we are often creatures of habit, choosing to plod through our thrice weekly, 30 minutes to an hour on the treadmill/cross-trainer or cycle, feeling happy that we are meeting our recommended weekly exercise quota.
But the lack of improvement, or rather the lack of anymore weight loss, prompts us to make a change and so we increase our distance and as we start to lose a bit more weight again, we are happy and so we keep plodding on. Then the weight loss stops again, we no longer feel quite so tired at the end of the session, and so we push our body some more, going for longer, further, and we keep on doing this. Therein lies the problem. Now our brain tells the body it is required to become more endurance-focussed so the body reacts, almost panics and begins to store energy as fat to fill its reserves to help us get through the miles. So... no more burning calories!
Another downside of endurance workouts is the repetitive nature of the movements. Without any variation, unless we have perfect biomechanics, which most of us don't (i.e. faultless posture and gait), these issues will get worse, dramatically raising our chances of injury. Add to this the risk of over-use injuries and the damaging effects of excessive endurance workouts on our hearts and Endocrine System (made up of the various glands throughout the body that regulate our bodily activities) and you can see why this myth needs blowing out of the water. High intensity interval training is done in 30-60 second spurts, with lots of variations and rest intervals for recovery, so even though there is impact on our joints, it is for a much shorter period of time. Research has shown that 10-12 minutes of High Intensity Interval Training pretty much equates to a good hour of steady-paced running on the treadmill. I know which I'd rather be doing!
HIIT WINS OUT EVERYTIME!
So remember, 2-dimensional workouts mean more wear and tear on those all important joints and muscles and the danger is we will plateau from the lack of variation in our routines; increasing its length to counteract the plateau just shocks the body into laying down fat in reserve, thus defeating the object of the whole workout and the benefits stop as soon as we do, unlike with interval training where you get another 24-48 hours of post exercise benefits, depending on the intensity of the workout. And therein lies the secret... When you step off the treadmill that's it. Finished, finito, the end. But with HIIT we burn more fat overall because of the Afterburn Effect. After HIIT, the next time we eat, the calories from our food will replace the glycogen used rather than be stored as fat. And that's got to be good news for us all.