“Cardiorespiratory fitness is inversely associated with long-term mortality with no observed upper limit of benefit.” This conclusion comes from a 2018 study published in the journal Cardiology (1) measuring all cause mortality in 122,000 participants under a treadmill based cardiovascular test.
Segmented into groups of cardiovascular health as such – Low, below average, above average, high and elite we can see how shifting from one group to another changes your risk of all cause mortality. For example, if you improve your fitness from low to below average you decrease your risk of mortality by 50%. If you can manage to move from low to above average it will decrease by 60-70%. When comparing this improvement vs the benefits of quitting smoking or reversing diabetes, increasing your cardiovascular fitness actually has a greater impact on mortality risk. These are incredible results. No single action moves the needle more for increasing longevity than improving cardiovascular health.
I still prefer to prioritize strength training for the vast majority of my clients and for myself but thats because outside of general lifespan, high performance living requires muscle mass, coordination and stability. In my opinion nothing brings a more balanced capacity to thrive in life than strength training. But you can not argue with the results of the studies on V02max and longevity, including this one that has concluded that there is no independent predictor of lifespan better than VO2max (2). Therefore I think every good trainer should be incorporating high intensity cardio training in their protocols, but you need to do it properly. General HIIT is not going to do it. your group classes at orange theory are not going to do it, yoga is not going to do it, even going for a moderate level run is probably not going to do it. They all have benefits, just not the kind I am talking about here.
How do you increase your VO2max?
VO2max has been defined as the slowest pace one reaches maximum oxygen consumption. Research from Wenger and Bell in Sports Medicine, back in 1986 concluded that protocols using 90-100% of VO2max bring about the biggest gains in cardiovascular fitness. They also concluded that workouts between 35-45 minutes, including rest periods do a better job in maximizing gains rather than shorter workouts. For those who are starting at a lower capacity, shorter intervals for shorter total workout time will help increase capacity. This is important because training to increase Vo2max is highly strenuous activity and overdoing it has diminishing returns.
Further evidence suggest that these high intensity interval sessions should be done 3-4 times per week for maximal improvement. Again, it’s important to note that this isn’t necessarily where you need to start off. Doing this 1 time per week is a perfectly fine place to start. Also if you are already at a high to elite cardiovascular fitness level, doing more than 4 sessions per week has diminishing returns. In my opinion it may be harmful to do this kind of training more than 4 times per week. Some studies ((3) (4) suggest that excessive cardio training may actually cause cardiovascular disease in the form of atrial fibrillation, malignant ventricular arrhythmia and release of troponin (this signals heart damage) and brain natriuretic peptide (also signals heart damage). Marathoners have also been seen to have kidney damage and lower cognitive functioning.
Reduced cognitive functioning seems to be related to high levels of cortisol in the blood. Regular high spikes in cortisol oxidizes certain brain cells, impairing memory, fine motor skills and response time for simple cognitive tasks. One interesting study carried out by the olympic studies centre showed cognitive discrepancies between long distance olympic athletes vs “strength” athletes, like power lifters or shot-put throwers, with cognitive abilities favouring the strength athletes.
Extremes never favour anyone. It’s a very simple and almost universal truth. But there is a time and a place for short bouts of intensity, so knowing the protocols for VO2max training is important. Here is what Dr. Peter Attia suggests:
- Aim for 3-4 VO2max training sessions per week.
- The ideal length of intervals sit between 3-8 minutes, he usually suggest 4 min.
- The rest interval should be equal to the work interval – so 4 minutes of recover if doing a 4 minute highest intensity cardio interval.
How you gauge your intensity level is important. In an ideal world you could use a VO2max monitoring system to make sure you hit your plateau. But this is not available for most people so you will have to use perceived rate of exertion (PRE). For this kind of training, it is basically “all out” exertion. Trying to hit somewhere at or over 90% capacity. We don’t say 100% because most peoples’ ability to sustain 100% is about 10 seconds. If you want to be able to last 4 minutes, just keep trying your best for that entire time. During the 4 minute interval, your top speed will inevitably waiver and that is fine, as long as your PRE is still 90%. Uncomfortable is too nice of a word to describe what this is like. I don’t want to scare you off, I just want to prepare you to ease your way into this. When I do this type of training, it is equally a test of mental fortitude as it is physical endurance. Every second is a bargaining game of why its okay to ease up a bit, or maybe I’ll stop early or do another interval later, .or maybe i’ll change my career and become a baker because I never want to do this again. If you every need proof that one brain can hold multiple personalities…its during VO2max training.
Depending on my clients fitness level I use various spins on Dr. Attia’s protocol. I usually begin with 1-2 minute intervals, repeated 3 times. I will often split the intervals into 60-70% intensity and 90% intensity. For example:
- 3 rounds of 2 minute intervals – 2 minutes on/ 2 minutes rest
- Of the 2 minute work interval, the first minute is done at 60-70% capacity – often called zone 2 training. in PRE terms, this would be a level where you could carry a conversation but with some difficulty.
- The second minute will be done at 90% capacity, or zone 5 training. Conversation is impossible.
After a few weeks of this, I may increase the zone 5 part of the interval, increase the number of intervals or increase the interval lengths. Any of these adjustments work, you just have to know your client and understand which one carries less of a mental burden. Trial and error may be your best tool. Keep records of their peak performance times.
The vast majority of testing is done on treadmills or bicycles. I prefer the rowing machine due to its low impact on joints and total body mechanics.
I will eventually do a deep dive into the testing science, biomarkers used for progress and the biology of how this kind of training increases metabolic health but I thought I would take it easy on the long form writing for a bit.
If you or anyone you know is interested in testing or training, please do not hesitate to contact us if you are in the Montreal area. Our personal training services are vast and include detailed evaluation systems and specialized training and nutrition coaching.
Joey