Running your next PB depends heavily on your aerobic energy system.
From 5km upwards, 98% of your performance is fuelled by your aerobic energy system.
When you run your easy-aerobic runs too fast, you add unnecessary and nonspecific stress to your physiological system. More often than not, the result is that your races never align with your training. Due to a lack of aerobic development and chronically elevated systemic fatigue.
Using a heart rate monitor to control your aerobic runs, you can ensure that you’re training for maximal aerobic capacity. The ideal training zone for most runners is Zone 1 - Zone 2. Typically, 75 - 88% of your anaerobic threshold.
Most apps like Strava and Garmin will auto-calculate your threshold and zones, but it’s worth double-checking your threshold by finding your average heart rate from the last 20min of a 10km - half marathon race.
“This is way too SLOW!”
“I can’t get fast running this slow.”
You’ll find that you’re forced to slow down on your ‘general’ runs when you start training with heart rate. You might even need to walk up the hills 🥺.
WHY YOU’RE SLOW
Lack of aerobic base.
Your aerobic energy system is the engine that powers your muscles during endurance exercise. Aerobic respiration occurs in the mitochondria, remember the powerhouse of the cell ⚡🧑🏫. The more mitochondria you have, the more energy you can utilise for muscular contractions, so you can move faster for the same effort.
Using a heart rate monitor, you can ‘monitor’ your aerobic capacity. When your aerobic capacity is low, your muscular contract level will also be low. Therefore, anytime you try to increase your level of muscular contractions, like running uphill, your heart rate will need to increase to deliver more oxygen and remove excess carbon dioxide (CO2) from anaerobic respiration, which generates lactate and occurs outside of the mitochondria.
When most runners start training with heart rate, they l