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Science AMA Series: I’m Niklas Ivarsson, co-author of the recent “why High Intensity Interval Training works” paper, AMA!
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Hello redditors of /r/science. I am Niklas Ivarsson, PhD student at Karolinska Institutet, Stockholm, Sweden. Yesterday you showed a great interest in our work regarding why high intensity interval training works. In the article we found that free radicals produced during high intensity interval training (HIIT) react in particularly with the ryanodine receptor, a critical calcium channel in excitation-contraction coupling. The reaction causes the channel to leak calcium from the specialized subcellular compartment (sarcoplasmic reticulum), into the cytoplasm. This causes a prolonged period of increased basal levels of calcium in the muscle cell. Increased baseline calcium acts as a signal for transcription factors important for mitochondrial improvements (e.g. Peroxisome proliferator-activated receptor gamma, coactivator 1 alpha (PGC-1α). HIIT, which is extremely intensive, causes a greater production of free radical than ‘regular exercise’. This results in the ‘damage’ to the ryanodine receptor, and subsequent ‘leak’ is more severe, and last longer than after a marathon. The ryanodine receptor modification and leak can be prevented if the exercise is done with strong antioxidants. Explaining why antioxidants prevents the positive effects of exercise (Ristow M. et al 2009) A little bit about me: I have a background in biomedicine. For my master thesis I decided to leave the world of cell culture and try my best in, what to me was a great unknown, physiology. For the master project I focused on insulin signaling in skeletal muscle. From there I kind of just stuck around in the research group of Professor Håkan Westerblad. During my master I got kind of bored. As per usual with large lab groups, there are often several “unfinished” projects laying around waiting for someone to come along. One of those side project eventually led us to applying for research money, namely ‘How does a muscle cell know it need to improve after endurance exercise’. We already knew calcium had to be involved somehow. Now 4.5 years later I am about to present my PhD thesis, which includes 6 (4 published, 2 waiting) different manuscripts around the subject of calcium’s role in training adaptation. Tl;dr I am a biomedical lab rat who stumbled onto the discovery that free radicals produced during exercise stress the muscle cell, which teaches the it to improve for the next shower of free radicals, resulting in improved endurance. I will be back later today to answer your questions, Ask me anything! edit: I will start answering your questions around 4pm USA East Coast Time edit: ok, you guys seem really interested so I’ll try and squeeze in some answers early edit: Thank you everyone for your questions. It is very late over here and time for me to go. Hope my answers satisfied your curiosity. //Niklas