As a personal trainer there’s a little saying I often throw at clients. It goes something like “let’s wait for the lactate to flush out and then we’ll go again (not me but them!)”. I’m sure they bristle when they hear my little quote- in fact some call me things-inappropriate things. I don’t mind. It just relays to me that their body is hurting. It’s where I want them to be. Not for too long. Just enough. But what do I really mean? What is ‘lactate’ and why do we have to wait for it to flush? Let me explain….Imagine you have a little house in the mountains. No, there is NO Wi-Fi and yes, there MAY be snakes (although probably not at this time of year in particular…). The first thing you need to do when you get to the house is start the fire in the lounge room. Next to the fire is a basket of kindling and newspaper (probably with Trump’s face all over it) so you use all this (not the basket) to start the fire. It’s roaring! This fuel source won’t last long. Let’s assimilate this scenario to the PHOSPHATE ENERGY SYSTEM. Phosphate (also known as phosphagen or alactic): ATP (adenosine triphosphate) and creatine phosphate (CP) are broken down to release energy for short, intense bursts of activity lasting between 10-15 seconds. The energy is produced without the presence of oxygen. (It’s like that moment you realise there IS no Wi-Fi). I’ve made/asked you to do your fifth round of 20 second boxing- like there’s no tomorrow. You want to punch my face and you think you’re going to arrest. That’s the phosphate phase. To keep the fire going, you need to walk to the woodbin on the verandah and grab some sticks. You walk back and put them on the fire and it is staying nice and hot. It took a little longer to get this fuel but you now have enough energy being provided for several minutes. This is like the LACTATE ENERGY SYSTEM. Lactate (also known as lactic anaerobic glycolysis): Glycogen is broken down without oxygen. This is called anaerobic glycolysis-to produce energy for intense activities lasting up to two minutes. As a by-product, a build up of HYDROGEN IONS develops acidosis in the muscle causing muscle discomfort and fatigue- the ‘burn’. I’ve just asked/ told you-with a little smile to do 15 burpees. You then think you’re going to possibly maybe vomit (not that I’m counting). Vomiting is the body’s defence mechanism (isn’t that cute?) to protect itself and to get rid of the hydrogen ions (H+) and build up of lactic acid. For many years, lactate or ‘lactic acid’ was thought to cause muscle fatigue but recent research states that the accumulation of hydrogen ions is responsible (not your trainer, nor your training partner). Lactate IS present but is not responsible for the ‘burn’ and fatigue .
Without lactate, you would not get fitter in response to training to the same degree you do with it. Lactate production during intense exercise stimulates a phenomenon called mitochondrial biogenesis after exercise. The mitochondria are little factories inside the muscle cells where aerobic metabolism occurs—that is, where oxygen is used to break down fats and glucose to yield energy. An increase in the concentration of mitochondria inside muscle cells is one of the major adaptations to training that improve endurance performance. And lactate makes it happen. This is one of the reasons high-intensity interval training is such a potent performance booster.Back to the fire. To keep it going for a longer period of time, you have to drive to the forest (no, there’s STILL no reception, suck it up), chop some wood, bring it back, stoke up the fire AND put the rest in the woodbin. There is now plenty of wood to keep you very warm -but it did take a long time to get it. Voila! the AEROBIC ENERGY SYSTEM. In the aerobic energy system, fats, glycogen and protein (in emergencies) are broken down to produce large amounts of energy in the presence of oxygen. Carbon dioxide (CO2) and water (H2O) are by-products of this process. So, you’ve just done a walk for a few minutes on the treadmill, have caught up on the gossip in a group session or are doing walking lunges across the oval (and gossiping at the same time). It will take you longer to get there- but you will burn some fuel.