I'm going to make a bet that of the athletes and non-athletes who read this post, less than 10% will have heard of the key term to which it relates. A term which, without exaggerating, is one of the most pivotal elements to your running. Let's see.
'Cardiac Drift'.
Heard of it? Don't worry if you haven't. But read on either way, because it's something you need to know. It's a bit sciency, this post, but it's useful.
So, the basics of a human cell are pretty easy to understand. In order to produce energy, a cell needs oxygen and sugar. Once it gets these things, it produces a circular power generation process in a part of the cell called the mitochondria. The by-products of this process are the energy itself, plus water and carbon dioxide as waste.
The thing is, not all of the energy it produces is kinetic (running). Thanks to the first law of thermodynamics (the rule that energy is never created, only transferred from one form to another), some of the energy is released as heat. The more intense the exercise, the more sugar and oxygen we need in, and the more water, carbon dioxide and heat come out. Simple.
So what's cardiac drift, and how does it relate to all this? Well, cardiac drift is the phenomenon that during exercise, heart rate will gradually increase even if overall effort remains the same. Take a look at the graphic below:
This occurs in part because of the rising temperature of the body. As the exercise continues, the body has to power the working muscles AND remove the excess heat. This is mostly done by the body shunting blood to the skin to radiate outwards. Hence you having a face like a tomato after a 5k. But this extra shunting of blood requires a higher heart rate to cope with increased demands being placed on it. And, as has been previously alluded to, a higher heart rate means fatigue will occur sooner due to the excessive production of metabolic waste products that occur when heart rate is very high (it's those waste products that cause the "burn").
All of this means that you can offset the effects of cardiac drift by managing your body temperature during a race or hard effort.
If it's a hot day, consider not just what the weather can do to your race times, but how you can combat the heat. Choose clothes smartly. Consider headwear. Don't overdress. Aid stations may have ice or water, and if its warm, you should slow down to take advantage of them.
Never be afraid to pour water over your head when you can. The evaporation of the water will help remove large amounts of heat energy. You might not be able to remove the cardiac drift completely, but you can keep it at bay for a little while. The convective and evaporative cooling effect of water cannot be overstated. Maybe it'll be just enough to get the PB you've been chasing. It's just another tool in your armoury against the clock, and against each other.
On that note, one final thought. A friend of mine shared a post last week that said: "I like to celebrate the achievements of others, rather than trying to outdo them all the time".
At Triathlon Nation that's what we're all about.
'Cardiac Drift'.
Heard of it? Don't worry if you haven't. But read on either way, because it's something you need to know. It's a bit sciency, this post, but it's useful.
So, the basics of a human cell are pretty easy to understand. In order to produce energy, a cell needs oxygen and sugar. Once it gets these things, it produces a circular power generation process in a part of the cell called the mitochondria. The by-products of this process are the energy itself, plus water and carbon dioxide as waste.
The thing is, not all of the energy it produces is kinetic (running). Thanks to the first law of thermodynamics (the rule that energy is never created, only transferred from one form to another), some of the energy is released as heat. The more intense the exercise, the more sugar and oxygen we need in, and the more water, carbon dioxide and heat come out. Simple.
So what's cardiac drift, and how does it relate to all this? Well, cardiac drift is the phenomenon that during exercise, heart rate will gradually increase even if overall effort remains the same. Take a look at the graphic below:
You'll see that this person is holding a steady pace but as they pass mile 10, their heart rate climbs over 155, eventually to 160. Over 160 is the point at which lactate will start to build, so it's a real issue, especially on hot days.
All of this means that you can offset the effects of cardiac drift by managing your body temperature during a race or hard effort.
If it's a hot day, consider not just what the weather can do to your race times, but how you can combat the heat. Choose clothes smartly. Consider headwear. Don't overdress. Aid stations may have ice or water, and if its warm, you should slow down to take advantage of them.
Never be afraid to pour water over your head when you can. The evaporation of the water will help remove large amounts of heat energy. You might not be able to remove the cardiac drift completely, but you can keep it at bay for a little while. The convective and evaporative cooling effect of water cannot be overstated. Maybe it'll be just enough to get the PB you've been chasing. It's just another tool in your armoury against the clock, and against each other.
On that note, one final thought. A friend of mine shared a post last week that said: "I like to celebrate the achievements of others, rather than trying to outdo them all the time".
At Triathlon Nation that's what we're all about.
Comments
Post a Comment