Outwardly, HIIT looks like a sharp and short (15-20 seconds) performance of one exercise, and then the same short periods of rest. However, what is the secret, why is it believed that HIIT promotes fat burning much better than classical cardio?
Theoretical Understanding of High Intensity Interval Training
A bit of theory. The energy unit in the body is ATP. During classical cardio exercise, our stores of glucose in the blood or glycogen in the mitochondria of cells are oxidized and as a result we receive 38 ATP molecules, which are consumed when exercising at an average or low pace. As soon as glucose and glycogen "run out", begins what we call fat burning - the oxidation of fatty acids from the body's stores.
With increasing training intensity, oxygen deficiency occurs, which is necessary for the oxidation of glucose and glycogen. In this situation, another reaction occurs - the body carries out the so-called anaerobic glycolysis. As a result, we get only two molecules of ATP and lactate lactic acid, which causes a burning sensation in the muscles. However, in fairness, we note that there is no fat burning in this process! The question logically arises - what is the secret of viit?
The first secret of vit is the afterburning effect (E. P. O. C - excess post exercise oxygen consuption). The second is an increase in insulin sensitivity.
The afterburning effect is a set of processes that occur in the body at the end of a workout. Our body has a fairly long metabolic response to training - it can take up to a day. In this case, the body consumes more oxygen and burns more calories. This post-workout effect is maintained exclusively with anaerobic glycolysis.
The second "secret" of viit is to increase the sensitivity of muscles to insulin. Insulin plays a transport role in the body - it delivers glucose to the cells, therefore, our body cannot function normally without it, but a large amount of it also negatively affects our health - it contributes to the accumulation of fat. With low tissue sensitivity to insulin, glucose is very difficult to enter the cell. With a high sensitivity of tissues to insulin, this process is facilitated. If we consider the process in numbers, then in the first case, for the penetration of one glucose molecule, at least 10 molecules must "approach" the receptor, in the second case, three are enough.
Features of interval training
One of the "consequences" of interval training is the increased sensitivity of muscle tissue to insulin. For us, this is important primarily because less insulin is needed for the normal functioning of cells, which means that it is synthesized less. Less insulin in the body contributes to improved fat burning.
Interval training should be as intense as possible - you do the largest possible number of repetitions in the shortest amount of time - this is the phase of anaerobic glycolysis, while lactate is excreted from the muscles during the rest period.
In classical cardio, we make sure to monitor the pulse so that it falls into the fat burning zone. You do not need to do this when performing a viit.
Another significant benefit of viit is that the workout does not last long, usually up to half an hour, including warm-up and stretching.
Viit is a very hard workout and they will go to those people who already have a certain physical training, both from the side of the musculoskeletal system and from the side of the cardiovascular system.
Viit is not recommended for those on a low-carb diet. This is primarily because interval training lowers blood glucose dramatically.
