The Safe and Effective Way to Exercise

You Were Built to Be an Exceptional Athlete

Not Olympic-level exceptional. Hunter-gatherer exceptional.

Your ancestors tracked game for hours—sometimes days—at a conversational pace. Eight to twelve miles daily. Low heart rate. Fat-burning metabolism. Sustainable forever.

That movement pattern built your cardiovascular system, your metabolism, your mitochondria, and your stress response. That's what human physiology evolved for.

Modern fitness inverted this. We sit all day, then do chronic moderate cardio that's too hard to build aerobic capacity and not intense enough to trigger real adaptation. Our bodies are confused. Our hormones are wrecked.

Heart rate training rebuilds your aerobic base—the persistence hunting foundation that represents 80% of human movement throughout history.

This is the missing piece in most fitness programs. And it's the most important piece.

Why Aerobic Base Training Matters

Low-intensity aerobic training does what chronic moderate cardio can't:

Manages Cortisol (Protects Your Adrenals)

Chronic cardio elevates cortisol. You're pushing hard enough to trigger stress response but not brief enough to recover quickly.

Result: Chronically elevated cortisol damages arterial walls, suppresses immune function, breaks down muscle tissue, promotes visceral fat storage, and tanks your thyroid.

Aerobic base training keeps you in the "conversational zone" where cortisol stays low. You're moving, but your body doesn't interpret it as a threat.

Your adrenal glands can recover instead of being constantly mobilized for fight-or-flight.

Builds Mitochondrial Density (Energy Production)

Mitochondria are your cellular power plants. More mitochondria = more energy production capacity.

Aerobic training—sustained low-intensity effort—is the strongest signal for mitochondrial biogenesis (building new mitochondria).

This isn't about "burning calories." This is about building the metabolic infrastructure that makes everything else work better.

Trains Fat Oxidation (Metabolic Flexibility)

At low intensity, you burn primarily fat for fuel. Your body learns to access stored energy efficiently.

This improves insulin sensitivity, stabilizes blood sugar, and reduces reliance on constant carbohydrate intake.

Your metabolism becomes flexible—able to switch between fuel sources based on availability and demand.

Supports Thyroid Function

Moderate-intensity exercise supports thyroid hormone production and T4-to-T3 conversion.

Chronic high-intensity training suppresses thyroid function through cortisol elevation and caloric deficit stress.

Aerobic base training hits the sweet spot: enough stimulus to support thyroid without triggering suppression.

Improves Cardiovascular Health Without Damage

Sustained moderate-to-high intensity creates oxidative stress, damages heart tissue, and can lead to cardiac fibrosis in chronic exercisers.

Low-intensity aerobic work strengthens the cardiovascular system without the inflammatory damage. You build capillary networks, improve cardiac efficiency, and enhance oxygen delivery—all without beating up your heart.

Reduces Injury Risk

Training at conversational pace keeps joints, tendons, and ligaments under manageable stress. You're building tissue resilience without creating microtrauma that accumulates into injury.

You can train frequently (5-6 days per week) without overtraining because the intensity never pushes into tissue damage territory.

The Maffetone Method: How to Find Your Heart Rate

Dr. Phil Maffetone developed the simplest and most effective formula for determining your aerobic training heart rate.

Here's how it works:

Step 1: Start with 180 beats per minute

Step 2: Subtract your age

Step 3: That's the TOP of your range

Step 4: Subtract 10 to get the BOTTOM of your range

Example (36-year-old):

• 180 - 36 = 144 (top of range)
• 144 - 10 = 134 (bottom of range)
• Training range: 134-144 beats per minute

Adjustments for Health Status

If you've had any of the following in the past year, subtract an additional 10 beats from BOTH numbers:

• Major illness
• Surgery
• Hospital stay
• Significant injury
• Currently taking medication
• Recovering from overtraining

Adjusted example (same 36-year-old with recent surgery):

• 180 - 36 = 144
• 144 - 10 (health adjustment) = 134 (new top)
• 134 - 10 = 124 (new bottom)
• Training range: 124-134 beats per minute

What This Heart Rate Feels Like

You should be able to hold a conversation comfortably.

If you can't speak in complete sentences without gasping, you're going too hard.

It will feel "too easy" at first. That's the point. You're training aerobic metabolism, not pushing cardiovascular limits.

Most people discover they've never actually trained their aerobic system—they've been doing chronic moderate cardio that's too hard to be aerobic and not intense enough to be true high-intensity.

How to Implement Heart Rate Training

Duration

30-45 minutes per session, 3-6 days per week.

Include:

• 10-minute warm-up (gradually increase to target heart rate)
• 20-30 minutes at target heart rate
• 10-minute cool-down (gradually decrease heart rate)

Total time: 40-50 minutes per session.

Activities That Work

Any activity that allows you to sustain your target heart rate:

• Walking (most accessible, lowest impact)
• Easy jogging (if your heart rate stays in zone)
• Cycling (great for those with joint issues)
• Swimming
• Hiking
• Rowing machine
• Elliptical

Choose activities you enjoy. The best exercise is the one you'll actually do.

Equipment

Heart Rate Monitor: Essential for accurate training.

Chest strap monitors (Polar, Garmin) are most accurate. Wrist-based monitors (Apple Watch, Fitbit) work but can be less reliable during exercise.

You need real-time feedback to stay in your zone. "Perceived exertion" isn't accurate enough, especially when building aerobic base.

Frequency

Start with 3 days per week. Build to 5-6 days per week over 2-3 months.

This is low enough intensity that you can train frequently without overtraining. Daily aerobic base training is sustainable and beneficial.

Timeline for Results

Weeks 1-2: Feels too easy, frustrating pace

Weeks 3-6: Pace increases at same heart rate (aerobic system adapting)

Weeks 8-12: Noticeable improvements in energy, fat loss, sleep quality, stress resilience

Month 6+: Aerobic base fully developed, ready to add more high-intensity work

Build your base for 3-6 months before increasing high-intensity frequency. Most people skip this step and wonder why they can't recover from hard training.

The Missing Pieces (And Why They Matter)

Aerobic base training is the foundation. But it's not the complete picture.

Your ancestors didn't just walk. They also sprinted (the kill), lifted heavy things (carrying meat back to camp), and rested (tribal recovery around the fire).

Here's how the other pieces fit:

High-Intensity Work (1-2x Per Week)

Brief, maximum-effort intervals trigger different adaptations: VO2 max improvement, power development, hormonal responses (growth hormone, testosterone).

This is the ancestral "sprint for the kill"—30-90 seconds of maximum effort, then full recovery.

You need this. But only 1-2x per week. More than that without adequate aerobic base leads to overtraining, injuries, and hormonal dysregulation.

For specific guidelines on high-intensity training frequency and implementation, see this guide on CrossFit and HIIT.

Strength Training (2-3x Per Week)

Functional, purposeful strength—lifting, carrying, pushing, pulling.

This builds muscle mass (metabolic reserve), bone density (stress resilience), and insulin sensitivity (metabolic health).

Heavy, moderate, or light—all have value. The key is moving load through space with proper mechanics.

Recovery (Daily)

Mobility work, yin yoga, walking, sleep, stress management.

Training without recovery is just breakdown. Recovery is where adaptation happens.

Meditation, gentle movement, and parasympathetic nervous system activation allow your body to rebuild stronger.

The Complete Framework

These pieces together create what's often called the "80/20 rule"—80% low-intensity aerobic work, 20% high-intensity intervals and strength.

For the complete ancestral movement framework and how all these pieces fit together, see this guide.

But you don't need the whole framework to benefit from this piece.

Start Here

Calculate your Maffetone heart rate. Get a heart rate monitor. Start walking, cycling, or swimming at that pace for 30-45 minutes, 3-6 days per week.

This alone will:

• Build aerobic capacity
• Improve fat oxidation and metabolic flexibility
• Manage cortisol and support adrenal function
• Stabilize blood sugar and improve insulin sensitivity
• Support thyroid hormone production
• Strengthen cardiovascular system without inflammatory damage
• Reduce injury risk
• Improve energy, mood, and sleep quality

You don't need high-intensity work yet. You don't need complex programming. You just need to move at a pace your body was designed for.

Build your aerobic base. Everything else becomes easier when you have this foundation.

Move like the exceptional athlete you were built to be.

For comprehensive nutrition and lifestyle strategies that support cardiovascular health and exercise performance, visit the Fuel Your Body pillar page.

For stress management and recovery strategies that complement your training, visit the Regulate Your System pillar page.

Ready to optimize your health and performance? Dr. JJ Gregor uses Applied Kinesiology and functional health approaches to help patients achieve their wellness goals at his Frisco, Texas practice. Schedule a consultation to discover how personalized exercise programming, nutrition strategies, and lifestyle optimization can support your overall health.