I used to swim in high school, and our lactic acid sets were one of the toughest workouts; they were short, all-out sprints followed by a couple minutes sitting on deck to let the lactic acid build up in our muscles. For some particular sets, we chugged small bottles of Gatorade between sprints. It became harder and more painful to sprint the more sets we did because our muscles were burning and heavy. Stomachs full of gatorade and pool water didn’t help either.
When I was sprinting, my muscles switched to anaerobic metabolism, breaking down glucose into pyruvate, which quickly converted into lactate as oxygen became limited. As we learned when the Cori cycle is in action, the lactate travels to the liver, where it can be converted back into glucose through gluconeogenesis and sent back to the muscles. However, during intense sprints, lactate builds up faster than the liver can process, which explains the burning sensation. Drinking Gatorade added another layer: the extra glucose provided my muscles with an immediate energy source, temporarily reducing the liver’s need to convert lactate into glucose. Still, the Cori cycle continued working just at a slower rate relative to production.
Understanding this process makes me appreciate how my body’s energy systems, nutrition, and performance are connected. Now I get why my coaches tortured us with these sets because over time, the body becomes better at both buffering and clearing that lactate, which is part of why lactic acid training builds endurance and recovery efficiency.
I had a similar experience on my swim team! We did ‘Mile Mondays’, which is a misleading name because the mile swim was just the *start* of practice. But I had the same sensation you are describing of my muscles starting to burn more and more as more lactate built up the longer I swam.
We also drink what seemed like gallons of Gatorade too, especially at meets. I hadn’t thought of the need for the glucose though until now!
That sounds super tough but is fascinating! It’s really cool to see the concepts we are learning applied to everyday tasks like sports practices. It would have been interesting if they explained why they chose to do this certain exercise. I think it would have made me more willing to do it if I knew how it would help my fitness long-term.
This was really cool to read about! It’s so interesting how your swim coach/team considered the way that the body produces lactic acid and uses glucose in order to implement that into your swim routine to build endurance and a better ability to recover. This is a great example of how biochemistry allows us to appreciate our body’s abilities and become maximally efficient. I wonder in what other ways strategies like these could be implemented in sports to improve endurance and power.
It’s really interesting to think about how repeated high-intensity work actually upgrades our mitochondria’s capacity for oxidation, increases our ability to clear out lactate efficiently, and enhances overall Cori cycle efficiency. Makes the training feel worth it!
This is super interesting! I love that you are able to connect specific sets that you did as a swimmer to the biochemical processes happening in your body during your workouts. Also, I think that it’s so cool that your coaches were able to think biochemically to help make you a better swimmer.