Empirical Cycling Podcast Watts Doc #54: Glycogen's Effects On AMPK
AMPK as Cellular Energy Sensor
- AMPK acts as a key cellular energy sensor responding to ATP/ADP ratio changes during exercise.
- It influences pathways including glycogen breakdown, fatty acid mobilization, and mitochondrial biogenesis.
AMPK Senses Glycogen Levels
- AMPK contains a glycogen binding domain in its beta subunit allowing it to sense glycogen levels.
- This binding regulates AMPK activity, linking glycogen availability to cellular energy signaling.
Low Glycogen Increases AMPK Activity But Doesn't Boost Performance
AMPK is a key cellular energy sensor activated by low glycogen levels, which inhibits AMPK activity when glycogen is abundant. Early research, like the 2009 paper discussed, found that AMPK has a glycogen-binding domain, allowing it to sense glycogen and thus regulate its activity accordingly.
However, despite the cellular mechanism showing AMPK activation with low glycogen, long-term studies and practical evidence indicate that training with low glycogen does not improve performance. In fact, it often leads to decreased next-day performance and potential metabolic disturbances.
This highlights a critical lesson: molecular mechanisms, while insightful for understanding cellular function, do not always translate to beneficial training interventions. The podcast emphasizes the importance of prioritizing actual performance outcomes over theoretically appealing molecular pathways.