If you’ve ever laced up a pair of runners, you know how hard it can be to pace yourself. Especially as you improve, it feels like every workout is a chance to push yourself just a bit further. You can quickly get into a mindset where each run must result in you giving it your all to consider it a success. Well, I’m here to say that this is our biggest downfall when it comes to running.
As a kinesiologist who is well-versed in exercise physiology, the most frustrating running mistake I see is probably not what you’re thinking. It’s almost counterintuitive, but the more and more I train clients, I’m realizing that most of us suck at doing the easy stuff. Unfortunately, science tells us it’s the slow, long runs where we should be spending a lot (if not most) of our training time.
“We work too hard on our easy days, and then we don’t have the base to push it hard enough on the hard days.” -Luke Jones
Why Slow Running Is Relevant for All Runners
It should be noted that the time spent completing slow runs will vary greatly depending on your experience level. For many elite marathon runners, they will spend up to 80% of their training volume here. If you’re a casual runner, this workout still has a place, but it may look like one session per week as opposed to 60+ miles. This may be an oversimplification, but for most distance runners, slow runs should be taking up at least 50% of training (with intervals, tempo runs, etc…taking up the rest).
The key to these easy efforts is that you’re staying below your aerobic threshold. This means that there is no transition to fast-twitch (type II) muscle fibers or anaerobic (fast-acting) metabolism. As for heart rate, you’ll be sitting around 50–65% of your max. Although everything within you will want to speed up your cadence and lower the mile splits, you must be patient. Trust me, this patience will pay off tremendously.
“Zone 2 training will upgrade your ‘battery’ so you can transform into the Tesla Long Range model.”
In the scientific literature, they often label this workout as zone 2 training. It is here that we can maximize fat oxidation to significantly increase endurance and improve fuel utilization. By taking the time to train in this zone, you’re developing the foundation on which your higher intensity efforts will sit. The reality is, no matter what distance or speed we’re training, the aerobic system will play a role — it’s just how our metabolism works.
To summarize up to this point, easy runs are the key to building your running volume while training to become more efficient at utilizing fuel. You’re essentially becoming a fat-burning machine. To use a metaphor, Zone 2 training will upgrade your ‘battery’ so you can transform into the Tesla Long Range model. Because of the low intensity, you have the capacity to increase the length of your longer runs and build a fantastic endurance base.
Here is a short excerpt from a previous blog post to hit this point home:
There is an abundance of upsides to Zone 2 training. To keep things short and sweet, here is a list of the primary outcomes (in no particular order).
Commit to training smarter, not harder, and you’ll experience…
Mitochondrial growth within muscle tissue (mitochondrial biogenesis).
Preservation of glycogen use (for the end when you need it most).
Improved lactate clearance capacity to boost recovery.
Increased stroke volume (due to left ventricle hypertrophy).
Increased plasma volume, along with elevated 02 transport and V02max.
Enhanced recovery through a decreased sympathetic drive.
Psychological benefits (you just ran for a long time, my friend).
An improved ability to utilize fat (Fat-Oxidation).
Notice how an enhanced fat-oxidation ability has a direct correlation to lower blood lactate levels (black boxes) at higher intensities.
If you didn’t catch all of that, just know that Zone 2 training transforms your performance and recovery. It does so by increasing the capacity of your heart, lungs, and nervous system. Whether it’s 5k, 10k, or a marathon, this training will have an immediate effect on your ability to stay fresh for longer and only dip into extra reserves when it’s absolutely required.
For the past 18 years working with professional and elite endurance athletes like cyclists, runners, and rowers, I have been able to see that zone 2 training is absolutely essential to improve performance. — Dr. Iñigo San Millán, PhD.
Whatever level you’re at with running, please make time for zone 2 training. If you don’t have the technology to observe your heart rate or other physiological measures, just do the talk test. As you perform your easy runs, ensure you can hold a prolonged conversation with someone quite comfortably. While this won’t guarantee you stay below the threshold, it will at least keep you accountable for maintaining an easy effort on your slow days.
I’m warning you now, this will feel extremely boring at first.
This is certainly the slow, mundane approach to aerobic training, but it’s so essential. Have patience, as the discipline to train well and pace yourself when necessary will pay off during race day. If you’re not interested in competitive running, this is still relevant as it constructs that valuable aerobic base as mentioned above.
Whether you’re running to win or running for life, slow runs need to be a part of your training regime.
This is a message to all runners: please don’t make the mistake of running hard every day. To optimize your endurance, conditioning, and metabolism, you must leave room for slow runs. While the volume or ratio of these efforts will vary based on your experience level, the thesis remains relevant for everyone.
Science tells us we should run slow, and we should absolutely listen. Hey, this may be a great chance to dive into a new podcast or finish that audiobook you’ve been neglecting. Whatever it takes for you to take your foot off the pedal, do it. You’ll be such a better runner for it in the long run (no pun intended).