The Catalyst

Chris Cooper

The Catalyst is your source for information about improving fitness and health. Once a week, host Chris Cooper of Catalyst Fitness bridges the gap between science and ground-level tactics in gyms and coaching practices. The Catalyst is perfect for coaches, trainers, nutritionists, athletes and general exercisers who want to learn more about training. Be sure to subscribe!

  1. 1d ago

    Zone 4: How to Get Through the Painful Zone (And Why It's Worth It)

    Zone 4 hurts. Not in a vague, uncomfortable way — in a specific, accumulating, burning way. Lactate is building faster than you can clear it. Every second feels longer than it should. And it is absolutely worth it. In this episode, Coach Chris explains exactly what Zone 4 is, why it produces the most direct improvements to your lactate threshold, and how to actually get through it — physically and mentally. The physiology first: the burning sensation in Zone 4 isn't caused by lactic acid itself. It's caused by hydrogen ion accumulation. Lactate is actually a useful fuel — your slow-twitch fibres burn it. Zone 4 training teaches your body to shuttle lactate from where it accumulates to where it gets burned, faster. The ceiling rises. What feels like Zone 4 today starts to feel like Zone 3. The formats: the Norwegian 4×4 protocol — four intervals of 4 minutes at Zone 4, 3 minutes active recovery between — is one of the most researched structures in endurance science. Tabata-style intervals (20 seconds on, 10 seconds off) work for most people at Zone 4 to 5 intensity. The mental game: dissociation — counting backward, the backward alphabet, chunking to landmarks — reduces perceived exertion and improves tolerance in ways research consistently supports. And a training partner produces a measurable physiological effect that makes Zone 4 efforts feel survivable in ways solo training simply cannot match. Book your free No-Sweat Intro at catalystgym.com/free-intro.

  2. Jul 27

    Zone 3: Training the Sweet Spot (Without Getting Stuck in the Grey Zone)

    Zone 3 has a reputation problem. Some coaches call it the grey zone — too hard for recovery, not hard enough for maximum stimulus. And when Zone 3 happens by accident, drifting up from what should have been a Zone 2 session, that criticism is fair. But the athletes who dismiss Zone 3 entirely are missing one of the most time-efficient tools in training: sweet spot intervals, deliberately executed at the top of Zone 3 for extended durations. In this episode, Coach Chris breaks down the crucial difference between grey zone grinding and intentional sweet spot training, and why that distinction changes everything. At sweet spot intensity — the upper edge of Zone 3 into the very bottom of Zone 4 — your body can use lactate as a direct fuel source. You're training your Type IIa muscle fibres to become more aerobically efficient. And you can sustain this intensity for 20 to 60 minutes, creating extended adaptation time that Zone 4 intervals simply can't match. You'll learn two formats that actually work: long sustained sweet spot intervals, starting at 2×20 minutes and building toward a single 60-minute effort, and over-under intervals — the structure used by athletes like Tadej Pogačar that alternates just below and just above threshold to train lactate clearance directly. Plus: how often to do this, how to structure recovery around it, and the one mistake that turns a great sweet spot session into wasted fatigue. Book your free No-Sweat Intro at catalystgym.com/free-intro.

  3. Jul 25

    How to Get the Most Out of Your Zone 2 Training

    Zone 2 training is the most talked-about topic in endurance and longevity science right now. But most people doing it aren't getting the full benefit — either they're working at the wrong intensity within the zone, missing key tactics, or skipping the pre-session prep that makes a real difference. This episode is not about how to know if you're in Zone 2. It's entirely tactical — specific things you can do before, during, and after a session to get dramatically more out of the time you're already spending there. Coach Chris covers four evidence-backed tactics. First: Zone 2 has a ceiling and a floor, and the research from Dr. Iñigo San Millán is clear that mitochondrial adaptation is strongest at the top of the zone, not the middle. Most people are training too conservatively. Second: nasal breathing is free real-time feedback for your intensity — and produces nitric oxide that improves oxygen delivery. Third: your diaphragm is a muscle, and warming it up with five minutes of deep belly breathing before your session delays respiratory fatigue and extends how long you can hold Zone 2 — the free version of what those Instagram breathing devices do. Fourth: session duration matters more than most people realize — 45 to 60-minute sessions produce meaningfully different mitochondrial adaptations than 20-minute sessions. Plus: the case for occasional fasted Zone 2 training and why frequency compounds the adaptation faster than any single-session tactic. Book your free No-Sweat Intro at catalystgym.com/free-intro.

  4. Jul 16

    METCONs Aren't Everything: Why Hard Workouts Alone Stop Working

    METCONs changed fitness. CrossFit popularized them, and before that, training to complete exhaustion in a group setting was unusual. Now it's everywhere — and for good reason. Metabolic conditioning workouts are one of the fastest tools for improving VO2max, building cardiovascular fitness, and triggering real body composition change, especially for beginners. But there's a problem. A lot of people are doing METCONs every single day and hitting a wall — weight loss stalled, strength plateaued, motivation tanked. This episode explains exactly why. Coach Chris Cooper breaks down what METCONs actually do well (and the research is solid), then covers three things they can't do on their own: they don't train your body to burn fat efficiently, they hit a strength ceiling without progressive overload, and daily high-intensity training leads to physiological burnout — not boredom, burnout — that causes most people to quit. The fix is the 80/20 principle: for every hard, high-intensity session, you need at least two zone 2 workouts — aerobic, conversational-pace training that builds your fat-burning base and lets your nervous system recover. Plus one dedicated strength session with progressive overload. This isn't about balance or injury prevention. It's about performing better, changing your body composition, and staying in the game for years — not just weeks. You'll get three specific prescriptions you can apply this week, whether you're brand new or stuck at a plateau. Listen at catalystgym.com

  5. Jul 10

    What Your Fitness Tracker Is Getting Wrong

    Nearly half of all adults now own a fitness tracker. Most are using it to make real decisions — when to push, when to rest, whether to even show up today. The problem: some of the most important numbers on that screen are significantly less accurate than the device lets on. In this episode, Coach Chris gives an honest breakdown of what wearables actually measure well — and where they quietly mislead you. The good news first: heart rate during exercise is reasonably accurate, sleep duration tracking is useful, and long-term trend data over weeks and months is probably the most valuable thing these devices produce. The bad news: calorie burn estimates are off by 30 to over 100 percent depending on the study. The Apple Watch has been shown to overestimate energy expenditure by as much as 115 percent. That number is the flashiest readout on your screen and also the least accurate. And recovery scores built from HRV — the green/yellow/red readiness ratings on Whoop, Oura, and Apple Watch — are based on a noisy, highly individual signal that varies with hydration, alcohol, stress, sleep timing, and room temperature. Research shows a single morning's recovery score is a weak predictor of actual workout performance. For anyone still building the fitness habit, letting a subscription algorithm decide whether to skip the gym is the wrong call. You'll also get three evidence-based ways to actually use your tracker effectively. Book your free No-Sweat Intro at catalystgym.com/free-intro.

  6. Jun 26

    The Truth About Testosterone (And Why Every Man Over 40 Is Being Sold TRT)

    If you're a man over 35, you've probably seen the ads. Tired all the time? Brain fog? Low drive? Struggling to keep muscle? The ad has an answer — it's your testosterone — and a clinic ready to fix it with an online quiz and a prescription. Testosterone prescriptions in the US jumped from 7.3 million in 2019 to over 11 million by 2024. In this episode, Coach Chris breaks down what's actually driving that explosion — and why the symptoms used to sell TRT online (tired, foggy, low drive, struggling in the gym) describe almost every overworked, under-slept man in his 40s. TRT is a legitimate treatment for genuinely low testosterone — it can improve insulin sensitivity, increase bone density, and meaningfully help men with real hypogonadism. But it also carries real trade-offs: increased blood pressure, clotting risk, and suppression of your body's own natural production. The FDA mandated new safety labeling in February 2025. What rarely makes it into the advertising: lifestyle factors move testosterone significantly. Losing excess body fat can raise testosterone production by up to 30%. Compound lifts produce the strongest hormonal response of any training style. A single week of 5-hours-a-night sleep dropped testosterone 10-15% in healthy young men. You'll learn what actually moves the needle before reaching for a prescription, and how to spot a clinic that's selling a business model rather than practicing medicine. Book your free No-Sweat Intro at catalystgym.com/free-intro.

  7. Jun 21

    Seed Oils: Should You Stay Away?

    Seed oils are toxic. They cause inflammation. They're driving the obesity epidemic. One prominent voice called them "worse than glyphosate, herbicides, and pesticides combined." In response, fast food chains switched to beef tallow, food companies started reformulating, and people across North America threw out their canola oil. But is any of this based on evidence? In this episode, Coach Chris Cooper breaks down the seed oil controversy from the ground up — what seed oils actually are, where the fear came from, and what the research actually shows. The science is consistent and substantial. A 2019 study tracking over 68,000 people across 13 countries found that higher blood levels of linoleic acid — the primary fat in seed oils — were associated with lower rates of cardiovascular disease and stroke. A 2025 study of nearly 1,900 people found higher linoleic acid linked to lower inflammation markers. A peer-reviewed 2026 paper in Nutrition Today concluded clearly: linoleic acid does not promote inflammation or oxidative stress. The anti-seed-oil movement has correctly identified a real health problem — ultraprocessed food. They've just pointed at the wrong culprit. The oil isn't what's making those foods harmful. You'll learn what's actually worth worrying about, why the omega-3 to omega-6 conversation matters but isn't solved by avoiding canola oil, and three evidence-based steps that address the real issue. Don't let a well-marketed panic distract you from what actually matters. Book your free No-Sweat Intro at catalystgym.com/free-intro.

About

The Catalyst is your source for information about improving fitness and health. Once a week, host Chris Cooper of Catalyst Fitness bridges the gap between science and ground-level tactics in gyms and coaching practices. The Catalyst is perfect for coaches, trainers, nutritionists, athletes and general exercisers who want to learn more about training. Be sure to subscribe!