How to use: Pre-record the narration below, then play it during your actual workout. As you exercise, you hear EXACTLY what your body is doing in real-time. Dual encoding: physical experience + auditory learning. This is the single most Pruimboom-compatible technique — he'd say you should be learning while moving anyway.
Format: A 20-minute bodyweight workout with cPNI narration between sets
(Record in a clear, coach-like voice. Leave pauses where indicated for exercise execution.)
Start moving. Light jogging on the spot, arm circles, whatever gets blood flowing.
As you begin, here's what's happening inside you right now:
Your sympathetic nervous system is waking up. Noradrenaline is being released from sympathetic nerve terminals throughout your body. Your heart rate is increasing — not because your muscles asked for it, but because your hypothalamus predicted you'd need more cardiac output and activated the response pre-emptively. This is feedforward control, not feedback.
Your adrenal medulla is releasing adrenaline into the bloodstream. Feel that mild buzz? That's catecholamines binding to beta-adrenergic receptors on your heart, increasing rate and contractile force.
Your blood vessels are doing something clever: vasodilation in skeletal muscle (beta-2 receptors), vasoconstriction in the gut and kidneys (alpha-1 receptors). Blood is being shunted from digestion to movement. This is why you shouldn't eat a big meal before training — your gut loses its blood supply.
Keep moving.
(60 seconds of movement)
Do 10 slow bodyweight squats. Ready? Go.
(pause 40 seconds for squats)
Good. While you rest, here's what just happened:
Your quadriceps, glutes, and hamstrings just contracted. Each muscle fibre that fired used ATP — and you blew through your stored ATP in about 2 seconds. Your creatine phosphate system donated phosphate groups to regenerate ATP for another 8 seconds.
Now, 10 seconds in, you've switched to anaerobic glycolysis. Glucose from blood and muscle glycogen is being split into pyruvate, yielding 2 ATP per glucose molecule. Fast but inefficient. Lactate is rising.
But here's the cPNI angle: that lactate isn't waste. It's a signalling molecule. Lactate activates GPR81 receptors on immune cells, modulating inflammation. It feeds the brain as alternative fuel. Lactate is an evolutionary survival molecule.
Do 10 more squats. Go.
(pause 40 seconds)
Rest. As you recover, your mitochondria are now fully engaged. Oxygen is arriving via increased cardiac output. Pyruvate enters the mitochondria, gets converted to acetyl-CoA, enters the Krebs cycle, and feeds the electron transport chain. Yield: 36 ATP per glucose. Eighteen times more efficient than glycolysis.
This is oxidative phosphorylation. This is why aerobic fitness matters — it's mitochondrial density and efficiency. Tom Fox in Module 10 hammers this: movement is medicine because it's mitochondrial training.
One more set of 10. Go.
(pause 40 seconds)
Do as many push-ups as you can with good form. Go.
(pause 45 seconds)
Rest. Feel your muscles trembling? That's motor unit fatigue — your brain is recruiting progressively larger motor units as smaller ones fatigue. This is Henneman's size principle.
Now, here's what exercise is doing to your immune system right now:
During this workout, your natural killer cells have surged into the bloodstream. Up to 300% increase. Your neutrophils are mobilised. This is the acute immune boost of exercise — catecholamines demarginate immune cells from blood vessel walls into circulation.
But after you stop — in the next 1-3 hours — there will be a temporary immune suppression window. Cortisol rises post-exercise and suppresses immune function briefly. This is the "open window" theory. It's why you might catch a cold after a marathon.
Pruimboom's insight: This is fine and ADAPTIVE if exercise is intermittent. The immune system oscillates — up, down, up, down. This oscillation is training. Just like muscle needs stress-recovery-stress cycles, so does immunity. This is intermittent living.
Another set. Go.
(pause 45 seconds)
Hold a plank for as long as you can. Go.
(pause — aim for 60 seconds)
Shake it out.
While you held that plank, your cortisol was rising. The HPA axis activated: hypothalamus released CRH, anterior pituitary released ACTH, adrenal cortex released cortisol.
Cortisol's job during exercise:
This is the acute cortisol response and it's HEALTHY. Problems only start when cortisol stays elevated chronically — that's when you get glucocorticoid resistance, hippocampal atrophy, visceral fat deposition, and immune dysregulation.
Exercise creates a cortisol pulse. Chronic stress creates a cortisol plateau. Same hormone. Opposite outcomes. Timing is everything.
Hold the plank again. Go.
(pause 60 seconds)
High intensity now. 30 seconds all-out. Go.
(pause 30 seconds)
Breathe. Your AMPK pathway just activated.
AMPK — AMP-activated protein kinase — is the cellular energy sensor. When ATP drops and AMP rises (like RIGHT NOW in your muscles), AMPK switches on. It does three critical things:
AMPK and mTOR are opponents. mTOR says "grow, build, proliferate." AMPK says "conserve, repair, recycle." Modern life is mTOR-dominant: constant feeding, no movement, no fasting. Exercise and fasting activate AMPK. This is the molecular basis of intermittent living.
One more round. 30 seconds. Everything you've got. Go.
(pause 30 seconds)
Walk slowly. Shake out your limbs. Breathe deeply.
As you cool down, your parasympathetic nervous system is taking over. The vagus nerve — cranial nerve X — is increasing its tone. Heart rate drops. Digestion resumes. Your body shifts from catabolic (breaking down) to anabolic (building up).
In the next few hours, something beautiful happens:
Your muscles will upregulate GLUT4 transporters — pulling glucose from blood without needing insulin. Insulin sensitivity improves for 24-48 hours post-exercise.
Your immune system will resolve its acute activation and return to baseline — but slightly more competent than before.
Your brain will release BDNF — brain-derived neurotrophic factor — which promotes neuroplasticity, memory consolidation, and neurogenesis in the hippocampus. You will remember what you studied today better because you moved.
Your mitochondria will begin biogenesis — making more of themselves via PGC-1-alpha activation. You are literally building more cellular power plants.
This is why Tom Fox teaches movement alongside nutrition. This is why Leo Pruimboom prescribes cold exposure, fasting, and exercise as medicine. Because these stressors, applied intermittently, train every system in the body.
You just studied cPNI and exercised at the same time.
Pruimboom would approve.
| Exercise Phase | Concepts | Module |
|---|---|---|
| Warm-up | Sympathetic activation, catecholamines, blood shunting | 3 |
| Squats | ATP systems (phosphocreatine → glycolysis → oxidative), lactate signalling, mitochondria | 10, 7 |
| Push-ups | NK cell mobilisation, immune oscillation, open window, intermittent living | 7, 10, 2 |
| Plank | HPA axis, cortisol pulse vs plateau, glucocorticoid resistance | 3, 7 |
| Burpees | AMPK vs mTOR, autophagy, insulin-independent glucose uptake | 10, 7 |
| Cool-down | Vagal tone, GLUT4, BDNF, mitochondrial biogenesis, PGC-1-alpha | 10, 3 |