Belly fat, along with fat elsewhere in the body, is a source of energy for your intense workout. So, the more you exercise the more belly fat burned. And, more intense workout similarly causes more belly fat to burn. Meanwhile, a signaling molecule called interleukin-6, also known as IL-6, causes the transfer of energy from belly fat to exercising muscles, needing the energy, during an intense workout.
First and foremost, visceral fat surrounds the abdominal cavity’s internal organs. Regrettably, visceral fat is really bad for you because it is responsible for cardio-metabolic diseases, cancer, dementia, and mortality. Also, visceral fat accumulates around your mid-section – resulting in an apple shaped body.
First and foremost, contracting skeletal muscles, during an intense workout, produces IL-6. Next, IL-6 enters the blood stream. Next, the liver and the white adipose tissue absorb IL-6 from the blood stream.
Upon entering the liver, IL-6 triggers conversion of glycogen to glucose. Next, the blood stream absorbs the glucose. Furthermore, the blood stream transports and releases the glucose to the starving exercising muscles.
Also, IL-6 receptors, on the white adipose tissue cells, capture IL-6 in the blood stream. And this triggers the hydrolysis of triacylglycerol. As a result, the adipose tissue cells release energy-rich free fatty acids and glycerol — a process known as lipolysis. Next, the blood stream absorbs the free fatty acids. And the blood stream transports and delivers them to the exercising muscles where they provide energy.
Above all, the amount of IL-6 produced depends directly on the intensity, duration and mode of the exercise. For instance, an intense workout like rowing, doubles the amount of IL-6 in plasma relatively quickly. On the other hand, with an endurance aerobic workout, like long distance running, the IL-6 doesn’t peak until later.
In addition, the amount of IL-6 produced is inversely related to the glycogen levels in contracting muscles. So, the glycogen starved muscles release huge amounts of IL-6. On the other hand, glycogen rich muscles release very little IL-6. Most of all, a huge and immediate release of IL-6 occurs when you exercise for a long time and/or you have an intense workout.
For instance, levels of IL-6 in blood are significantly enhanced after 30 min on a treadmill, with peak levels occurring after 2.5 hours on the treadmill. Other studies didn’t measure IL-6 levels while running but at several times after running stopped. These studies reported the highest IL-6 levels immediately after the running stopped. This was, then, followed by a rapid decline.
Most noteworthy, the kinetics of the IL-6 response differs in strength training exercises such as concentric and eccentric exercises. First of all, a concentric exercise is one where contractions shorten the muscle, while eccentric exercise is one where the contractions lengthen the muscle.
In most exercises, the targeted muscle is working to perform the action. And the muscle does the work by shortening itself – known as concentric focused action. While during the return the targeted muscle relaxes. And the muscle does so by returning to its original length – known as eccentric focused action.
For example, in an intense workout like the biceps curl, the concentric portion occurs when you bend your elbow and bring the weight toward your shoulders. And the muscles do this by shortening themselves. While the return is eccentric focused because when you relax your muscles, they lengthen to go back to their previous length.
So, when you do concentric exercises, the increase in IL-6 is related to the duration of the exercise. Most noteworthy, there is logarithmic relationship between the increase in IL-6 and duration of the exercise. And, IL-6 levels decline after completion of the concentric exercise to reach original levels within a few hours.
On the other hand, eccentric exercises cause only a modest increases in IL-6 levels. And the IL-6 levels peak at some time after the exercise ends. However, IL-6 levels stay elevated for several days after.
This role of IL-6 was recently demonstrated with obese adults doing an intense workout. In fact, exercise bikes were used, in the intense workout, to burn fat. As a result, these adults saw a decrease in their visceral abdominal fat. Above all, the demonstration clearly showed that IL-6 played a key role in the loss of visceral abdominal fat.
In fact, the before and after amounts of visceral fat was measured using magnetic resonance imaging techniques. And, a noticeable loss of visceral fat was measured. Regrettably, using a weight scale to measure body weight changes would lead to invalid results. This is because exercising increases muscle mass while also decreasing body fat. So a better approach to measuring visceral fat is to use a tape to measure waist circumference.
So what’s the takeaway.
First, it’s not any particular exercise that’s important but whether you get an intense workout doing the exercise. In fact, an intense workout is one where you sweat during the workout. Because if you don’t break a sweat, the intensity of the workout is low. Which means the body is expending little energy during the workout. And while you will burn some fat, the amount burned would be very little.
So what kind of exercises qualify? Most of us can easily name running, bicycling, fast walking, rowing, or paying tennis. But there are many others that may not be obvious because it’s not clear you can do them with intensity. For example, strength training with weights lower than your maximum, especially if you go through your workout fast enough to feel your muscles getting tired. While, on the flip side, even running wouldn’t qualify for an intensive workout, if you only do a leisurely jog that doesn’t even cause you to breathe much quicker than your normal rate.
By the same token, you also have to exercise for a sufficiently long duration. For example, because your muscles can’t take it anymore, you may finish your particular weight workout quickly. So if that happens, do a weight workout using different muscles. And, because you are doing several such workouts in sequence, you are effectively doing an intense workout over a long period of time.
Now, going back to the example of jogging. You can make up for your slow jog by jogging for a long period of time. For instance, jogging for at least one hour, would definitely tire you out, meaning you expended a lot of your energy.
In conclusion, it’s not enough to only workout. Indeed, to successfully lose belly fat, it’s necessary to also change your diet so that you don’t eat back the fat you lost by your workouts.