Being out on the hill we all get that burning in our muscles and the fatigued feeling that causes many of us to stop and take a rest. I have heard people use the word “lactic Acid build up” as the reason behind fatigue and the next day training pains in your limbs. After lots of research I found this is not completely accurate. Yes during high intensity exercise we produce Lactic, however, we also produce Hydrogen Ions(Acid) and Pyruvate which cause all the above issues not the Lactic!.
What are Hydrogen Ions & Pyruvate?
Hydrogen Ions are a product of exercise. A biochemical reaction splits ATP into ADP to create energy and creates waste product. When we are exercising normally our respiration will clear such waste products like Hydrogen Ions(Acid) and Pyruvate(Acid) from our muscles, preventing an acidic build up(Acidosis). When we are exercising at much higher intensity our body cannot remove this waste product from our muscles and lactate is produced from Pyruvate and Hydrogen Ions, this is designed to slow down the build up of acids (working as a buffer). Lactate is carried away easier in the blood than in the separate forms thus removing and reducing the acid in the muscle at a quicker rate!
How does acid in my muscles develop into fatigue?
The muscles require a consistent PH of 7.2 in order to work effectively! should the PH drop then the muscles will start to shut down in order to protect them from damage. With the build up of Hydrogen Ions and Pyruvate, the muscle PH will fall below its preferred operating PH and will start to shut down. Lactate is simply a by product of this process and is simply a buffer to slow down acidosis in muscles (Acid build up). If the acids were not turned into lactic acid your muscles would become fatigued in a much shorter time!
Why do I get the ache in my muscles the next day ?
Once a muscle is pushed to its limit it will start to become inflamed as its gone through a process of muscle cell damage. The body then promotes an elevated release of various metabolites into the tissue surrounding the muscle cells in order to repair the muscle. Most sports professionals will call this DOMS (Delayed Onset Muscle Soreness) This is a normal process and some studies have found that taking an anti inflammatory can help reduce such effects, however, this is not always the best remedy.
Try reading the articles below for more detailed explanation!
So how do I reduce fatigue during exercise!
Providing the body produces less Acid than can be removed then you wont suffer fatigue. When Lactate amounts start to rise higher than the rate of removal then you will fatigue. The only way to reduce the burn is hard work. Plenty of mixed exercises and a mixture of high intensity and low intensity will improve your lactate threshold!Their is no pill or sports drink that can avoid the hard work needed!
The simplest way to improve your lactic threshold is to increase your duration of exercise and the frequency of exercise, Once your aerobic energy system becomes more efficient it will clear the waste in your muscles and reduce fatigue. Pushing into your anaerobic energy system will also help reduce acid build up as it will train your body to remove it more efficiently. Try finding a gentle hill and run up then walk back down! You will find that over time your recovery times will decrease and you will feel less fatigued at the top! Increase the angle of the hill and length to increase difficulty!
For the more advanced!
Interval training is another proven way to increase lactic threshold. Working at the top end of your Aerobic limits will produce large amounts of Acid and Lactate which your body will learn to remove faster and faster each time. Personally I use Heart rate as a marker for intensity, My muscles can handle the Acid and Lactate under 175 BPM but anything higher and I start to see reductions in my performance! Pushing this limit each time is hard(85%-90% MAX BPM) but when mixed with a good cardio regime can see huge benefits! I would only use a high intensity session once per week as I believe it should be an addition to an exercise program that allows recovery!
high intensity training should only be considered by those who are already AEROBICALLY fit and should not be tried by BEGINNERS. the heart will be stressed and this can provoke heart issues or death!
In order to keep this blog simple I have avoided using terms like Aerobic and Anaerobic, they will only complicate this subject and will still not help with the understanding of Lactate! For more information on why we produce more Lactate during high intensity activity and the differences between Aerobic and Anaerobic I have provided links below
This blog is intended to simplify the whole process of acidosis. I have omitted certain detail to keep it simple and have copied some sentences from research journals as they put it better than I could!