Endurance Training Guide: How to Improve VO2 Max, Aerobic Fitness, and Longevity
endurance training is not only beneficial for powering through your local 5k and marathon but is also imperative for optimal health and longevity metrics. Being more aerobically fit drastically improves your body composition, metabolic and cellular function, improves muscle and heart tissue, and decreases your risk of chronic disease. This article will dive into what you need to know about endurance, how to train for overall endurance, define and outline how to improve your vo2 max, and outline a weekly schedule you can follow to improve your health and positively influence your longevity. Let’s start with how your body powers various endurance efforts.
how does your body power endurance efforts?
your body relies on three overlapping energy systems designed to create energy; the phosphagen system, anaerobic glycolysis, and aerobic oxidative metabolism.
the phosphagen system uses phosphocreatine readily stored in muscle TO rapidly generate ENERGY. this energy system fatigues fast but produces energy very quickly which is why it’s ideal for creating energy for short fast bursts like sprinting or jumping that last anywhere from 0-10s.
anaerobic glycolysis is the intermediate energy system that uses glucose or stored glycogen to rapidly produce energy. this energy system creates energy at a faster rate compared to aerobic oxidative metabolism but is slightly more fatigue resistant compared to the phosphagen system. this system is ideal for powering high intensity efforts that last anywhere between 10 seconds and 2 minutes.
finally, aerobic oxidative metabolism produces energy at the slowest rate but is most resistant to fatigue since it uses oxygen to generate energy from fuels such as carbohydrates and fats. this system is great for long endurance efforts where you’re maintaining a pace that is easy —for you— and semi-comfortable to hold for an extended period of time. this system becomes the dominant energy source during continuous efforts lasting several minutes to multiple hours.
now that we know the three different energy systems let’s break down what’s going on in your body when you do cardio so we can train for endurance appropriately and understand why we are doing certain types of workouts.
what happens in your body when you do cardio?
for endurance efforts you can think of these three layers as a series of steps to produce movement, (1) cardiac output, (2) peripheral oxygen extraction, and (3) movement economy. let’s break these down.
cardiac output is the total amount of blood pumped per minute and is determined by stroke volume and heart rate. stroke volume is the volume of blood ejected from the heart with each pump, heart rate is the total amount of pumps your heart does per minute. the lower your cardiac output, the less oxygen can be delivered to working muscles during exercise.
peripheral oxygen extraction is the ability for your tissues, mostly muscle tissue, to take in oxygen from the blood. all energy systems mentioned prior (phosphagen, anaerobic and aerobic) occur in your cells, so if oxygen delivery is limited, aerobic metabolism becomes less effective, forcing your body to rely more heavily on the anaerobic systems.
lastly, movement economy is related to your form while doing a movement. if you compare the running form of an elite marathoner versus a weekend warrior you’ll notice the marathoner looks like they’re running almost effortlessly with very little unnecessary movement compared to the weekend warrior. the marathoner in this case has a better movement economy which means they’ll expend less energy per step. overtime this will help them exert less energy with each step thus helping them sustain whatever pace they are moving at for a longer period of time. training to improve your movement economy comes from strength training and other methods while training to improve the other levers of the aerobic system are determined by specific cardio focused sessions. let’s talk more about that.
how to train for endurance
Training the aerobic system is pretty simple overall, 75-90% of your training should be in heart rate zones 1 and 2 and 10-20% of your training should be in heart rate zones 4 and 5.
Training in heart rate zones 1 and 2 improves ventricular filling, plasma volume, stroke volume and peripheral oxygen extraction, all of which are correlated with improvements in cardiac muscle and cellular function. this type of training improves the heart’s ability to pump and circulate oxygen-rich blood to working muscles. For non-elite athletes, or folks not training for a specific event, 3-4 hours per week of zone 1 and 2 training is recommended. if you can, try to make one of your sessions in this heart rate zone last anywhere between 75-120 minutes as extended sessions in this heart rate zone will have a greater impact to mitochondria and cellular function. The other weekly sessions can be 30-60 minutes. if you can’t do that long of a session, then frequent sessions of 30-45 minutes more often can produce similar adaptations.
the other 10-20% of your training should work your upper cardiac limit. one well studied protocol for training in these heart rate zones is the Norwegian 4x4 interval method. 4 minutes of near maximal intensity work (90-95% of your max heart rate) followed by a 4 minute rest and repeated 4 times. These suck, and should be very hard. that’s the point. If you’re not sucking air at the end you’re probably not pushing yourself hard enough.
endurance training is very straightforward but unfortunately people still end up plateauing, here’s why.
the biggest mistake people make with endurance training
the biggest mistake i see is people spending far too much time in the ‘grey zone’ zone 3. the reason for this is either their ‘slow and easy’ zone 1 and 2 sessions creep into zone 3 and/or their ‘hard interval’ sessions are not hard enough and they don’t get their heart rate up past zone 3.
i call zone 3 the grey zone because, while there is some benefit in training in this heart rate zone, the people who are benefiting most from sessions in this zone are most likely already well conditioned. if you are new to training or simply working to improve your overall vo2 max, you’ll get much more benefit from spending more time in the lower heart rate zones and specific time in the elevated heart rate zones. so drop your ego at the door, make your easy sessions easy and your hard sessions hard, try to avoid excessive time in the middle.
now what about vo2 max? you may have heard this thrown around as an important predictor of longevity. let’s define it and cover specific training you can do to improve your vo2 max.
what is vo2 max?
your vo2 max is the maximal amount of oxygen you can use to power aerobic activities. this scale ranges from below 20 ml/kg/min for sedentary individuals to above 90 ml/kg/min for elite endurance athletes. It’s important to note that everyone has a ceiling to how much oxygen they can use, even the fastest marathoners. through proper training you can raise your current ceiling which will increase your capacity to sustain endurance efforts for longer. let’s discuss how to do this.
training to improve your vo2 max
when you search up vo2 max training on google you’ll find a plethora of specific hard interval routines which, when starting out, will definitely help improve your vo2 max. However, there comes a point (speaking for the non-elite population) where your vo2 max will plateau if you only do cardio in this hard interval fashion; For most active individuals I’ve seen, the plateau occurs between 50-55 ml/kg/min. if you fall into this category here are three ways to check yourself and reevaluate your plan if necessary;
(1) you’re spending too much time in zone 3
for most, this is this main issue and addressing this will help break through the plateau. spending the bulk of your training in zone 3 means either your easy sessions aren’t easy enough or your hard sessions aren’t hard enough —or a combo of the two. excessive time in zone 3 simply accumulates fatigue without maximizing cardiac adaptations. you’re making yourself tired without getting any benefit from it.
(2) you’re not doing enough long aerobic work
this may seem counterintuitive since vo2 max specific workouts are purposely hard and short. this is true. however, in order to continue to elevate your vo2 max and overall conditioning you need to have a large and strong aerobic base. it’s the same thing when looking to get stronger in the gym. You can only get so far if you only lift heavy and don’t have a strong capacity to build off of. long slow sustained efforts improve mitochondrial density, cellular function, oxygen exchange, and tissue metabolism — all of which play a role in aerobic conditioning. the larger your base the higher your ceiling.
(3) no true vo2 max work
your vo2 max training sessions should be hard. you should be breathing extremely hard, unable to speak during your intervals, and near your maximal heart rate. this is because these sessions primarily train your upper cardiac limit and maximal oxygen delivery, both of which require higher intensities to accomplish these outcomes. if it’s hard to get to this level on your own, group classes can be an excellent avenue to achieve this. You really only need one session per week of this, and two max if you’re more trained and you’re able to recover fully between sessions. but really, one is more than enough.
weekly routine to improve your endurance and Vo2 max
at minimum,
1 zone 1-2 session that lasts between 75-120 minutes
1 true vo2 max interval session (4x4 intervals)
example weekly routine,
Monday - 60 minute zone 1-2 cardio (optional)
tuesday - strength train
wednesday - 4x4 vo2 max intervals
thursday - 60 minute zone 1-2 cardio (optional)
friday - strength train
saturday - 90 minute zone 1-2 cardio
sunday - 30 min zone 1-2 cardio (optional)
