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Improved endurance without training? Researchers believe they have found the ‘on-switch’ in muscles responsible for the effects of endurance training.
Improved endurance without training?
Attention! Here comes a nerd alert:
If you think you know enough with the knowledge that cardio improves endurance, then skip this article. If you want to know more about it, but think that knowledge of energy systems, muscle fiber types, and maximum heart rate is enough, then you can also swipe away. However, if you’re someone who asks a new question with every new insight, then by all means keep reading! Especially if you get excited about names like PGC1α and PGC1β.
With a bit of basic knowledge, you already know that endurance training like long-distance running or cycling uses the oxygen system for energy. You may also already know that you mainly use slow muscle fibers for this. You may also already know that these muscle fibers have many mitochondria, the energy factories of a cell. You may have also known that providing optimal delivery of blood and oxygen and removal of waste products is important.
That knowledge is enough to know, for example, how through cardio at moderate activity you can make yourself able to run longer. You go for regular runs and something happens in your body that improves your endurance. Actually, that’s all you need to know. Unless you can’t run, of course, or cycle. There are people with physical limitations that prevent them from improving their condition through training.
If you know exactly which processes are controlled by this training and how that subsequently leads to improvements in condition, you may be able to skip the step of training altogether. If you find the ‘on-switch’, you may be able to press it in other ways. That’s at least the thought of researchers at the Salk Institute.
“The secret of cardio”
You can argue that the researchers at Salk have solved part of the mystery. I emphasize ‘part’ because endurance is determined by different factors. The weak link determines how well you can perform. Your body must, among other things, be able to deliver more blood and oxygen. Lungs, heart, and vessels must become more efficient. In addition, the muscles must be able to process this amount in order to actually perform better.
ERR gamma protein
The researchers discovered in Ronald Evans’ laboratory that the protein ERRγ (ERR gamma) is responsible for many of the beneficial effects of endurance training.
“ERRγ enables endurance training,” explains Evans. Evans is a professor, director of the Gene Expression Laboratory, and co-author of the study. “It increases the number of mitochondria, the energy factories of the (muscle) cell. This leads to more blood vessels, the small capillaries, being created. These supply more oxygen, remove more waste products, and help the muscle recover.”
The protein ERRγ is part of a process that is initiated when you do endurance training. First, the PGC1α and PGC1β proteins are activated. These then stimulate 20 other proteins associated with the energy supply of (skeletal) muscles and endurance training. One of these is ERRγ, a hormone receptor that then activates certain genes.
The researchers mainly wanted to know what the main player in this process is. Looking for ‘the on-switch’ so to speak. For this, they studied mice in which the PGC1α and PGC1β proteins were disabled. In some of those mice, they selectively increased ERRγ in skeletal muscles. This way, they could determine the role ERRγ and the PGC1α and PGC1β proteins play independently of each other and jointly.
The ‘on-switch’ for endurance training
Disabling the PGC proteins had a negative effect on the energy supply of the muscle cell and endurance. However, this was restored when ERRγ was increased. They discovered that ERRγ is necessary for energy production by activating genes that produce more mitochondria. This also increased blood circulation.
By increasing ERRγ in mice without PGC, these mice could run up to five times longer than mice without PGC1 and with normal ERRγ levels.
Now the researchers hope to find other ways to press this on-switch without training. This includes treatments for people with weakened muscles and muscle atrophy, among others. These are the groups that cannot, or less effectively, train to achieve these health effects.
However, there is a much larger group for whom this button may be pressed more often.
References
- Weiwei Fan, Nanhai He, Chun Shi Lin, Zong Wei, Nasun Hah, Wanda Waizenegger, Ming-Xiao He, Christopher Liddle, Ruth T. Yu, Annette R. Atkins, Michael Downes, Ronald M. Evans. ERRγ Promotes Angiogenesis, Mitochondrial Biogenesis, and Oxidative Remodeling in PGC1α/β-Deficient Muscle. Cell Reports, 2018
- https://linkinghub.elsevier.com/retrieve/pii/S2211124718302286
- https://www.salk.edu/news-release/salk-scientists-find-power-switch-muscles/
