Why is HIIT so effective? Keerthana Balamurugan

HIIT, or High intensity interval training, has become increasingly popular over the last couple of years among casual gym goers and professional athletes alike. It is the concept of being able to achieve faster and consistently better results in a shorter period of time rather than spending an hour on the treadmill that attracts the populace. We know that HIIT works, but what is the reason behind it? And why are we only figuring this out now?

High intensity interval training essentially consists of performing a variety of vigorous exercises for around minute each in order to increase your heart rate and push your body to its limit, with short breaks in between. You repeat the cycle until your body eventually tires out. This workout technique has caught the interest of many as intense bursts of exercises seem to be having positive results.

The increasing popularity of HIIT has piqued curiosities of many researchers around the globe. A professor of physiology and pharmacology at the Karolinska Institute in Sweden conducted a study in search of the scientific reason behind the success of this type of workout. The study consisted of two groups of volunteers: one group rode a stationary exercise bike as fast as they could for thirty seconds, taking three-minute breaks in between, the other performed the same exercise but for a much longer period at a maintainable pace. Blood and muscle samples were taken from the two groups before and after the exercise. The results showed a much higher concentration of calcium ions being released for the group that had performed the intense exercise. (released from where? To where?)

During exercise, calcium ion channels open in the muscle cells, allowing calcium ions to pour into the cellular fluid. This increase in calcium ions signals molecular machinery in the muscle cell to contract, causing the entire muscle to flex. Tests showed that after a HIIT workout these calcium ion channels were fragmented. The break down of these receptors meant that calcium ions were able to leak into the cell continuously. This causes stress to the cell, but only a little bit, as the calcium ions are only released in small amounts. Cells react to this stress by increasing their endurance, making them better equipped to withstand more intense sessions of HIIT. Subsequently, there comes a point where after years of doing HIIT that the body is adapted fully to the rigorous exercises. The muscles no longer react dramatically to the intense exercise. In conclusion, this form of exercise is great for fast results but there will come a point where the body will slowly stop showing quick results due to adaptability. Another amazing conclusion that scientists discovered was that even after 24 hours of performing HIIT, the muscles are still breaking down fat in your body.


Click the link below if you are inspired to try out a session of HIIT.


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