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STILL IN MOTION
Because slowing down isn’t in the plan.
THIS WEEK'S STORY
About three years ago I went through a stretch where most of my cardio felt good. I was working hard, sweating, heart rate was up. I felt like I was doing the right thing.
My resting heart rate didn’t change. My recovery didn’t improve. My endurance on long hikes was essentially the same as it had been for years.
A sports cardiologist I eventually spoke with asked me to describe a typical cardio session. I told him: moderate to hard effort, twenty to thirty minutes, a few times a week.
“Moderate to hard,” he said. “Meaning what exactly?”
I described something that would be a six or seven out of ten on a perceived exertion scale. Breathing heavily, could speak but not comfortably.
He nodded. “You’re training in no man’s land. Too hard to build the aerobic base. Not hard enough to build peak capacity. Most people over 60 do this.”
He wasn’t wrong. And what he described next changed how I think about cardiovascular training entirely.
THE MAIN MESSAGE
Cardiovascular fitness after 60 rests on two distinct physiological systems that require two distinct training intensities. Almost all recreational exercisers train exclusively in the middle — and develop neither system effectively.
Zone 2: The aerobic base.
Zone 2 is a low-intensity effort where fat is the primary fuel, the aerobic mitochondrial system is doing the work, and the effort is sustainable for 30 to 90 minutes. The talk test: you can hold a conversation comfortably in full sentences. Heart rate: roughly 60 to 70 percent of your maximum. It feels almost too easy. That’s correct.
Zone 2 training is where mitochondrial density is built, cardiac stroke volume improves, fat oxidation efficiency develops, and long-term cardiovascular health is most significantly influenced. Research on Zone 2 for adults over 60 shows consistent reductions in resting heart rate, improved blood glucose regulation, and extended years of functional independence.
VO2 Max Work: The peak capacity.
VO2 max — the maximum rate at which your body can consume oxygen during effort — is one of the strongest single predictors of all-cause mortality. It declines with age and is trainable at any age. High-intensity interval work — 2 to 4 minutes at near-maximal effort with equal recovery — is the primary stimulus for VO2 max improvement.
The 80/20 model:
- 80 percent of cardiovascular training time at Zone 2 intensity — building the aerobic foundation.
- 20 percent at high intensity (Zone 4 to 5, true intervals) — stimulating VO2 max adaptation.
- Almost nothing in the moderate-hard middle (Zone 3) — where most recreational exercisers live and where neither system adapts optimally.
The practical implication: most people need to slow down on easy days and go harder on hard days. Both adjustments feel wrong at first. The easy days feel too slow. The hard days feel genuinely hard. That’s the correct response.
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Stretch of the Week: Standing Doorway Chest Opener with Thoracic Extension
Why: Cardiovascular training requires the chest and thoracic spine to be fully mobile for efficient breathing. This stretch addresses both the anterior chest and thoracic extension simultaneously in a standing position — a new combination not covered in previous issues.
How to do it:
Stand in a doorway, both forearms against the frame at shoulder height, elbows at 90 degrees
Step one foot forward and lean your entire chest gently through the doorway
Feel the stretch across both sides of the chest and the front of both shoulders simultaneously
Now gently tilt the chin slightly upward and let the thoracic spine extend — deepening the stretch into the upper chest
Hold 30–40 seconds, 3 rounds
Tuesday goes deeper with three pre-cardio mobility variations targeting the chest, thoracic spine, and rib cage as an integrated sequence.
Strength Move of the Week: Loaded Farmer Walk with Nasal Breathing
Purpose: A Zone 2 cardiovascular and strength hybrid. Nasal-only breathing enforces Zone 2 intensity automatically — the moment you need to breathe through your mouth, the load or pace is too high.
How to do it:
Hold a moderately heavy dumbbell or kettlebell in each hand, arms at sides
Stand tall — ribs down, shoulders back, gaze forward
Walk at a steady pace breathing exclusively through the nose
If nasal breathing cannot be maintained, lower the load or slow the pace
Walk continuously for 5 to 10 minutes, rest, repeat 2 to 3 rounds
Thursday expands with three cardiovascular formats mapped to Zone 2 — walking, cycling, and the 4x4 interval protocol for VO2 max.
Suggested Equipment: Heart Rate Monitor or Chest Strap
Zone 2 training requires knowing your actual heart rate, not estimating by feel. A wrist-based smartwatch provides adequate accuracy for Zone 2 monitoring during steady-state exercise. A chest strap is more accurate for interval work where heart rate changes rapidly.
Saturday covers the full cardiovascular toolkit: zone calculations, monitoring options, and training apps that make zone-based training trackable.
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THE TAKEAWAY
Most people are training in the least productive cardiovascular zone. Slowing down on easy days and going genuinely hard on hard days produces measurably better adaptation. Zone 2 is not a concession to aging. It is the foundation that makes everything else work better.
YOUR TURN
What does your current cardio look like? Same effort level every session, or do you vary intensity intentionally? Have you ever tried true Zone 2 — where it feels almost too easy? Reply and tell me where you’re starting from.
Still moving forward,
— The SIM60 Team
simsixty.com · Educational content only. Not medical advice.
