Improving Cardiovascular Health

Where I'm at

I'm currently trying to increase my running frequency from once a week to 3-4 times a week. In my early 20s I was able to run 10km easy. I'd estimate that at my peak, I would be able to run somewhere between 10km and a half marathon. But now at 33, I'm barely able to run 5km, and it doesn't feel easy at all.

The Fick equation

$\text{VO}_2\text{max}$ is widely considered to be the gold standard for aerobic capacity and cardiovascular health ^[1]1Åstrand, P-O. & Rodahl, K.. (1986). Textbook of Work Physiology. 3rd ed.. McGraw-Hill. pp. 295–353., but other factors also play a part, notably: lactate thresholdThe exercise intensity at which blood lactate begins to accumulate faster than it can be cleared — typically 75–85% of VO₂max in trained athletes., movement economyThe oxygen cost of moving at a given submaximal pace. Two runners with identical VO₂max can differ by 20%+ in how much oxygen they need to hold 4 min/km., and muscle powerThe rate of force production, especially relevant for the final kick or hill surges. Distinct from strength — measured in watts, not kilograms..

Essentially, these are the components of Cardio, but how does it relate to improving our own cardiovascular system?

$\text{VO}_2\text{max}$ is often anecdotally compared to the size of an engine. HIIT (High-Intensity Interval Training) has been proven to be the most effective method. e.g. 400m repeats or "hill sprints" forces the heart to adapt to extreme demand.

Lactate Threshold or Moving the "Redline" - this is likened to how long you can drive fast without overheating the engine. It is the point during exercise where lactate builds up in your blood faster than your body can remove it. This is exercised through tempo or threshold runs - sustained efforts that feel "comfortably hard" - usually a pace you could maintain for about 40-60min if you had to.

Running/movement Economy or Increasing Efficiency - it's how efficient our engines are at using oxygen to run a certain speed. This is improved through Low-Intensity Steady State (LISS), often called zone 2 training. Strength training focusing on legs and a stable core also reduces "power leaks" in our running form.

The "80/20" framework is commonly studied for cardio health - 80% of your runs should be low intensity (zone 2), and 20% of your runs should be high intensity (intervals or tempo).

Where I want to be

What I really want to do is to challenge myself to firstly get back to what I could do in my prime, and then challenge it.

How do I get there?

1. Build frequency of runs, not distance or speed
   I've known that this was my main problem for a long time - the pace I'm comfortable at (7:15-7:30min/km) is too fast for my current aerobic base. Running at this pace tires me out too easily, making me unable to run longer distances where I would otherwise be able to if I reduced the pace to 8:00min/km or even slower. Practically I feel like there is a limit to how much I can run if I were to lower the pace even more, but maybe something for another time.
2. Make almost every run geniunely easy
   Following the 80/20 rule - 80% easy, 20% hard, this is well established - easy volume builds the aerobic engine that lets you eventually run faster without the all-out feeling
3. Following a reasonable 6 week starting block
   3 runs a week, 2 runs of 30-35min very easy, 1 "long" run of 40-60min

Tracking and Monitoring

Easy runs should sit at roughly 65-75% max HR. Max HR is roughly estimated with 220 - age, but a hard treadmil effort for 4-5min is more accurate.

Other things to track:

• resting HR each morning
• body weight before and after outdoor runs (sounds like too much effort to consistently maintain)
• RPE(rate of perceived exertion)
• sleep duration and quality
• pace at given HR over time

Glossary