It doesn’t take long before you realize that mountain biking requires a lot of cardio fitness. This makes cardio training one of the most popular subjects for riders looking to improve their performance. But what is cardio fitness and are the types of cardio training usually recommend to riders the best way to improve it?

At its most fundamental level, your cardio fitness comes down to how well your body can utilize oxygen. This is one of the reasons that VO2Max is considered an important part of performance in endurance sports – the more oxygen you can take in, the more oxygen your body has to work with.

However, the reason that VO2Max isn’t able to predict your performance is because there is a lot more going on than just how much oxygen your body can take in. Your body also has to be able to efficiently use that oxygen or else it doesn’t matter how much you can take in.

This is why athletes with a lower VO2Max can beat athletes with higher scores. Because they are able to make more efficient use of the oxygen they are taking in they can outperform someone who is able to take in more oxygen but can’t use it efficiently.

And while VO2Max is largely genetic and can’t be improved much after an initial training period, your ability to utilize the oxygen you do take in can be trained and improved to a much greater degree.

To better understand how we can do this, let’s first look at what our body uses oxygen in the first place. This will make it easier to understand what we want to focus on in order to improve how efficient we are with oxygen.

1 – Oxygen is transported via red blood cells in the body. The more red blood cells we have, the more oxygen we can carry in and the more metabolic “leftovers” we can carry out.

2 – The red blood cells release the oxygen where it is needed. The easier your red blood cells can offload the oxygen the faster you can get it where it needs to go, which is into the working muscles.

3 – Your muscles take in the oxygen and use it to produce energy. If they can’t get enough oxygen then they start to produce energy anaerobically and produce lactic acid. Lactic acid build up creates a build up of hydrogen ions, which contribute to muscle fatigue. The better your muscles can use oxygen and tolerate the build up of lactic acid the harder you can work before fatigue sets in.

4 – Your muscles offload metabolic “leftovers” from these processes, more notably Carbon Dioxide (CO2), and the red blood cells carry these leftovers to the lungs to be exhaled before the process starts over again with the next breath. It is the build up of CO2 that triggers the feelings of breathlessness so the better we can tolerate that build up the harder you can work before triggering that feeling.

Based on this you can get a blueprint for what you want your cardio training to accomplish. Not only do you need to be able to take in oxygen, you need to be able to transport it to where it is needed, offload it, utilize it and be able to tolerate the build up of the “leftovers” from this process. If you can do that then you will be able to make better use out of the oxygen you can take in.

So how do you accomplish this? As funny as it may sound, the answer lies in holding your breath.

Strong breath holds have been studied for a while and it is surprising to me that so few of us know about them or how to use them. Some of the effects of breath holds as they relate to our goals are…

1 – Signaling the release of EPO from the kidneys. This hormone creates a signal for the maturation of red blood cells in the bone marrow. This results in more red blood cells to carry oxygen.

2 – Improving CO2 tolerance. This has a double effect for us since CO2 is needed to offload oxygen from the red blood cells (known as the Bohr Effect) and a rise in CO2 is what triggers the breathless feeling, meaning that in improved tolerance means we can have more CO2 in the system – making it easier to offload oxygen – without triggering that feeling.

3 – Improved buffering of lactic acid build up/ hydrogen ions. One of the goals of hard interval training is to build up lactic acid in order to improve how well the body can tolerate the hydrogen ions that they produce. Strong breath holds create a build up of lactic acid since you don’t have more oxygen coming in, forcing the body to create energy anaerobically. This creates an improved buffering effect, meaning you can tolerate more lactic acid build up before succumbing to the fatigue the hydrogen ions help to trigger.

4 – Increased lung capacity. This helps us not only take in more oxygen but also makes it easier to offload CO2 and other leftovers from the metabolic processes in the cells.

5 – Increased strength of the respiratory muscles. While holding your breath the brain continues to signal your breathing muscles to contract, meaning that you are performing an isometric contraction during the breath hold. This increases the strength of these muscles, making them able to work harder with less effort.

As you can see, the effects of breath holding cover just about everything we need to improve how efficiently we can take in and utilize oxygen. Regular cardio training, including high intensity intervals, can only check a couple of these boxes, meaning that if you aren’t doing breath holds as part of your cardio training then you are missing out.

Another benefit to breath hold training is that since the breath holds are creating the stress for the body to adapt to then you don’t have to work as hard physically. You can create the metabolic environment needed to see the improvements without creating a lot of wear and tear on the body.

So how do you use breath holds as part of your cardio training? It is actually pretty simple.

A workout I like to start people out with consists of 5 warm up breath holds and 5 strong breath holds. Here is how to do it:

Warm Up Breath Holds
– Hold on Exhale while Walking for 10-15 paces
– Stop and do 30 seconds of Nose Breathing
– Repeat 5 times

Breath Hold Workout
– Hold on Exhale for 20 paces, walking for first 5 and then starting to run
– Minimal Nose Breathing for 6 Breaths
– Normal Nose Breathing for 1 minute
– Hold on Exhale for 25 paces, walking for first 5 and then starting to run
– Minimal Nose Breathing for 6 Breaths
– Normal Nose Breathing for 1 minute
– Hold on Exhale for 30 paces, walking for first 5 and then starting to run
– Minimal Nose Breathing for 6 Breaths
– Normal Nose Breathing for 1 minute
– Hold on Exhale for 35 paces, walking for first 5 and then starting to run
– Minimal Nose Breathing for 6 Breaths
– Normal Nose Breathing for 1 minute
– Hold on Exhale for 40 paces, walking for first 5 and then starting to run
– Minimal Nose Breathing for 6 Breaths
– Normal Nose Breathing for 1 minute

I call this type of workout CO2 Tolerance Training, since one of the main goals is to increase the levels of CO2 in order to allow your body to adapt to those higher levels. This means that you will be triggering that panicky “I can’t breathe” feeling, which is triggered by rising levels of CO2.

This will give you the chance to learn how to better deal with this feeling, allowing a chance to create a wedge between the uncomfortable stress and how you react to it. Creating a feeling of “relaxed suffocation” is one of the goals of this type of training which will pay off a lot when you get pushed into that feeling when performing.

Because this workout isn’t physically stressful you can perform it 3-6 times a week. If you are riding your bike a few times a week then this is probably all you need to do from an “extra cardio” standpoint since riding your bike is the most specific type of cardio training you can do. If you aren’t able to ride on a regular basis then having a more traditional cardio workout once or twice a week would help to keep your cardio rounded out.

Remember that the point of training is not to get better at training, it is to get better at our sport and daily activities. Part of this is understanding how to create the metabolic environment we need to trigger the changes we want.

While breath hold training may not look as intense or leave you panting in a pool of your own sweat they do create the necessary environment needed to improve how efficiently we utilize oxygen in several ways that regular cardio training simply can’t. Give this workout a try for a few weeks and see for yourself how this “easy” workout can improve your cardio where it matters the most – on the trail.

Until next time…

Ride Strong,

James Wilson
MTB Strength Training Systems