The anaerobic system is always working even in deepest sleep.
When you're starting to get out of breath, this is due to accumulated hydrogen ions being buffered by the bicarbonate system a product of which is extra carbon dioxide which has to be breathed out. Added to this is the fact that you are at or near your maximal oxygen uptake.
So when people talk about "going anaerobic" this is what they are referring to, but it's not really accurate, because you are using much more aerobic metabolism than anaerobic.
True, but there is a lot more involved. The bicarbonate system is just one player.
The lactate produced from glycolysis shuttles to the liver where it is converted back to glucose to be reused again. The pyruvate produced during glycolysis (anaerobic) is oxidized and converted to Acetyl COA, NADH, and CO2. The Acetyl COA is used in the Krebs cycle (aerobic). More CO2 is created during the Krebs cycle. The NADH produced is used during the electron transport chain (aerobic).
It's all tied together on a continuum.
You are right that we are mostly reliant on the aerobic system the longer the race goes.
The anaerobic system is always working even in deepest sleep.
When you're starting to get out of breath, this is due to accumulated hydrogen ions being buffered by the bicarbonate system a product of which is extra carbon dioxide which has to be breathed out. Added to this is the fact that you are at or near your maximal oxygen uptake.
So when people talk about "going anaerobic" this is what they are referring to, but it's not really accurate, because you are using much more aerobic metabolism than anaerobic.
Ah, thanks. I had just assumed that it was obvious that the shift was gradual and not like an on/off switch! I'll be more careful in using the the term anaerobic in the future. Again, thanks.
It is gradual, but the reverse of what you were taught. In a race, your metabolism goes gradually more aerobic.
The anaerobic system is always working even in deepest sleep.
When you're starting to get out of breath, this is due to accumulated hydrogen ions being buffered by the bicarbonate system a product of which is extra carbon dioxide which has to be breathed out. Added to this is the fact that you are at or near your maximal oxygen uptake.
So when people talk about "going anaerobic" this is what they are referring to, but it's not really accurate, because you are using much more aerobic metabolism than anaerobic.
True, but there is a lot more involved. The bicarbonate system is just one player.
The lactate produced from glycolysis shuttles to the liver where it is converted back to glucose to be reused again. The pyruvate produced during glycolysis (anaerobic) is oxidized and converted to Acetyl COA, NADH, and CO2. The Acetyl COA is used in the Krebs cycle (aerobic). More CO2 is created during the Krebs cycle. The NADH produced is used during the electron transport chain (aerobic).
It's all tied together on a continuum.
You are right that we are mostly reliant on the aerobic system the longer the race goes.
You missed out proton buffering from Lactate production in Glycogenolysis and proton accumulation from Glycolysis and how to avoid the latter.
I've made an interesting observation with my HR since being pregnant with twins. It seems like my body doesn't allow me to go anaerobic, which I guess is good because I later read that anaerobic cardio is dangerous in pregnancy. It is just weird that my body seems to do it without me trying. I track my HR with a Whoop band I've had for over a year. Before I was pregnant, I'd have lots of runs in the anaerobic zone. Of course the fatigue of pregnancy has slowed me down a ton and I'm only running maybe 20 mpw or so (down from 50-60), but I figured I'd hop in a couple of 5Ks and try some light speed work just to keep me sane. At no time has my HR gone anaerobic even though the effort was there. In my 5K last weekend, I looked at the data and my HR was almost a straight line across the total amount of time spent running, including the warm-up, even when my pace sped up or slowed down.
Congratulations on your running Stephanie, you sound like you are having fun. I'm sure you can inspire others.
We don't actually "go anaerobic". It's a misunderstanding of biochemistry. There is no anaerobic cardio. The high end of your heart rate is high end aerobic/VO2max territory. I don't know if it's because you are breathing for two that your heart rates are lower though, I haven't looked into this.
There's definitely not much scientific info out there about running while pregnant, but just from personal experience, it's pretty crazy how much and how soon it has affected my running. I'm just 11.5 weeks along, not really showing yet, but it was a night and day difference in how I felt, how slow I got and how long (or not) I could go. I'm trying to do some more research, but I'm no expert. Everything from hormone levels to blood volume has an effect. All this time I thought the had part would just be the weight gain and bump, but that hasn't even really happened with me yet.
I just run my first marathon and I experienced the increased HR described in this post. I'm very curious to understand better what when wrong so that I can correct it for future races.
Here is what happened:
I have followed a 8 week training plan (after a long summer doing a lot of slow cycling).
During my long runs (32Km was the max), I was running at 5'/Km with no muscle fatigue and with still energy in my body to push longer. My avg HR was just below 160bpm.
I noticed that if my HR is around 170bpm, I get tired (burnt) really quickly so my strategy for the marathon was to keep my HR around 160, and not to reach 170, but at the final push.
Looking at this data, I was confident I could run 42Km at 5'/Km (I had already run 32Km easily at this pace).
It's worth saying that my best (and longest) training run was after 5 days of very heavy exercise. I was supposed to be very tired, but after a good night sleep, my body seemed... awake and rather fresh.
The marathon was just the opposite. I did a 3 week taper period, reducing volume to half each week, but keeping the intensity. I followed a carbs load-up of 3 days and focused on rest and good sleep.
Before the start of the race, my HR was at 100bpm! And 120bpm at the start! This is way above my usual HR at rest (60-80bpm), but I thought it was the adrenaline, the nerves or the overdose of carbs and sugar.
When I started running, my HR was 15-20bpm above my training HR. I was going at 170bpm, yet much slower than the pace I wanted to follow. I was unable to reduce the HR and after 30' I felt exactly what I had felt while training at 170bpm: I was burnt!
After that point, the rest of the race was an agony, I was unable to maintain a decent pace. I missed miserably my usual half marathon time and thereafter... I feel embarrassed for having had to walk.
My conclusion is that training or race, I must keep a HR below 160bpm not to get burnt. But I wonder why this happened?
Nerved for the race?
Stress for being surrounded by racers?
Adrenaline?
Too many gels?
Taper too long?
Lack of hydration (training I don't drink the first hour so I don't think it applies as the issue happened before)?
My conclusion is that training or race, I must keep a HR below 160bpm not to get burnt. But I wonder why this happened?
Nerved for the race?
Stress for being surrounded by racers?
Adrenaline?
Too many gels?
Taper too long?
Lack of hydration (training I don't drink the first hour so I don't think it applies as the issue happened before)?
Thank you!
My "resting" HR before a ran is in the 85-105 range. It's normal. Your body is anticipating the race and your HR is higher due to anticipation (aka nerves). That would go away immediately after the start so your later problems are probably due to something you did out of the ordinary.
Did you drink an abnormally high amount of coffee before the start? Did you have a lot more sugar intake than normal within 60 minutes of the start? That might account for the struggle you experienced.
I had a decent size carb-rich breakfast 3 hours before the race with an expresso coffee. So I wouldn't say excess of caffeine.
I had more than usual sweet food though: honey for breakfast (-3h), a fruity-gel (-1h) and a powergel at race start. I also started having powergels from the beginning every 30', but during training, I would take the first one at 1h30' (and every 30' thereafter).