The Next Move

Dr. Richard MacKenzie is an associate professor specializing in human metabolism and a clinician working at the intersection of exercise physiology, metabolic health, and stress. He is the author of Stress Tested: How The New Science of Stress Hormones Can Transform Your Health.
In this episode, Richard unpacks what stress actually is from a physiological perspective, how acute and chronic stress differ, and why chronic stress can quietly undermine insulin sensitivity, recovery, sleep, and training adaptations.
We also explore how stress shows up in metrics like heart rate variability, glucose variability, and fuel metabolism, why mindset and perception dramatically alter stress responses, and how exercise, nutrition, caffeine, sleep, and even cold exposure can either buffer or amplify stress.
Episode breakdown:
00:00 – Who is Dr. Richard MacKenzie?
00:16 – Why write Stress Tested now?
02:23 – What is stress?
04:28 – When does stress turn from helpful to harmful?
04:52 – How does chronic stress show up day to day?
06:15 – Can stress actually be measured?
07:41 – What does a personal “stress dashboard” look like?
09:59 – How changeable is stress with mindset?
13:59 – Does exercise reduce stress—or add to it?
15:29 – Is stress one of our biggest health threats?
19:56 – What hidden stressors are we missing?
26:06 – Can diet increase—or reduce—stress?
36:04 – What has stress research changed for Richard?
41:05 – What’s next: protein, metabolism, and future research?


This is a public episode. If you would like to discuss this with other subscribers or get access to bonus episodes, visit johngetstrong.substack.com

Gommaar D’Hulst is an exercise physiologist at ETH Zurich and the mind behind the WOD Science YouTube channel, with a background rooted in CrossFit and a growing focus on HYROX and hybrid endurance sports. Through his research and applied lab work, Gommaar bridges elite performance, physiology, and real-world training decisions for functional fitness athletes.
In this episode, Gommaar breaks down the key physiological differences between CrossFit and HYROX, why HYROX is best understood as an endurance-dominant sport, and how muscle fiber types, VO2 max, lactate threshold, and anaerobic power shape performance. He shares insights from lab testing with elite athletes—including novel functional ramp tests using burpees and thrusters—explains why fatigue dramatically alters running economy in HYROX, and explores how tools from endurance science (like threshold training, Zone 2 work, and power metrics) can be adapted to functional movements. We also dive into interference effects, fueling strategies, and where sports science is headed as HYROX continues to professionalize.
Episode breakdown:
00:00 — Intro: Gommaar (ETH Zurich) + WOD Science + CrossFit → HYROX
00:24 — CrossFit vs HYROX demands: longer duration, lower intensity, aerobic bias
01:40 — Can you excel at both? Specialization, rising level, and the Tia example
03:13 — Is HYROX endurance or strength? Why it’s primarily endurance (and sled/turf impact)
04:48 — Muscle fibers 101: slow vs fast twitch and what they’re built for
07:50 — Why strong powerlifters can struggle: strength vs strength-endurance
11:01 — HYROX strength training: when (and if) low-rep work fits in the season
12:17 — VO2 max + lactate threshold: what they are and why they matter
15:56 — Elite CrossFit VO2 findings: lower-than-expected on the bike + specificity issue
18:27 — Functional ramp test: burpees + thrusters protocol + what lactate curves show
21:55 — Run → lunges/deadlifts → run: fatigue increases VO2 cost (running economy drop)
26:02 — What predicts HYROX performance beyond VO2: fatigue-resistance across stations
28:22 — Heart rate: good for running, limited for stations + why VO2 can drop in strength work
34:15 — Interference effect: separating strength and endurance (same-day vs split) outcomes
46:53 — Nutrition rapid-fire: carbs (timing + high intakes) and bicarb/creatine practicality


This is a public episode. If you would like to discuss this with other subscribers or get access to bonus episodes, visit johngetstrong.substack.com

George Hearn is a life coach who came into coaching through a high-achieving academic and corporate path—studying Geography at Cambridge, spending years in strategy consulting, and then moving into the startup world—before realizing he was more drawn to helping people design intentional, fulfilling lives
In this episode, George breaks down what coaching actually is (and why it’s often not about giving advice), how he structures sessions using tools like the Wheel of Life, Ikigai, and visualization, and how everyday practices like journaling, distraction-free walks, and even AI chatbots can support self-reflection. He also shares the behind-the-scenes of building his coaching business from scratch—finding clients, learning marketing and sales on the fly, navigating uncertainty, and building the support network needed to go all-in.
Episode breakdown:
00:00 — What a coach actually does
01:01 — Coaching vs therapy, consulting, and mentorship
03:04 — George’s life coaching origin story
10:34 — The Wheel of Life: mapping the key areas and finding gaps
13:27 — Prioritization + Pareto: focusing on what actually moves the needle
14:04 — Ikigai: purpose at the intersection of skills, love, value, and need
16:26 — Visualization: the “80-year-old you” exercise
18:59 — Self-coaching tools: journaling for clarity + momentum
21:34 — Thinking walks: default mode network and the “exam question”
24:11 — Using chatbots for reflection: powerful, but don’t outsource decisions
28:20 — Building the coaching business: learn-by-doing + finding clients
32:28 — Living with uncertainty: risk, confidence, and growth mindset
35:23 — The solo founder problem: building a support network
38:22 — Developing coaching skills: listening, communication, self-work
41:01 — When self-improvement becomes obsessive: staying balanced
44:32 — What George is curious about: why people don’t aim for a 10/10 life
46:44 — Closing reflections


This is a public episode. If you would like to discuss this with other subscribers or get access to bonus episodes, visit johngetstrong.substack.com

Gabrielle Nicora-Baker is an Elite 15 HYROX athlete who came into the sport from a pure strength and bodybuilding background, with almost no running experience before her first race in 2024. In less than a year, Gabrielle progressed from her first mixed doubles race to competing in elite fields. In this episode, Gabrielle breaks down how her strength base accelerated her rise in HYROX, how she trains and fuels for elite racing, and what she’s learned from racing frequently, hiring a coach, and chasing a Worlds-level performance.
Episode breakdown:
00:00 – Intro
01:48 – Strength background and rapid rise into elite competition
03:57 – Bodybuilding years: training splits, progressive overload, big lifts
06:09 – Early running volume (~20km/week)
08:11 – How strong do HYROX athletes really need to be?
11:11 – Current training structure: thresholds, speed, long runs (~15 hrs/week)
17:28 – Home gym setup: treadmill, ergs, bikes, and winter training
21:43 – Nutrition shift from bodybuilding to endurance fueling (carbs, prep)
26:39 – Race weaknesses: wall balls, burpees, fatigue management, mindset
32:42 – Learning the sport fast: podcasts, racing reps, hiring a coach
36:02 – Worlds relay experience + doubles vs solo racing
39:42 – 2026 goals, testing curiosity, Phoenix prep + where to find Gabrielle


This is a public episode. If you would like to discuss this with other subscribers or get access to bonus episodes, visit johngetstrong.substack.com

Owen Silver is a software engineer and experienced triathlete who ran a 60-minute HYROX in his very first season of racing. Owen and I also teamed up for the HYROX Pro Doubles in Melbourne, where we finished in 58:52. In this episode, Owen breaks down the training principles that helped him cut five minutes off his HYROX time in just six months.
Episode breakdown:
00:57 – Why Owen switched from triathlon to HYROX
02:06 – “HYROX is a runner’s sport”: endurance base vs strength
05:11 – Owen’s triathlon benchmarks (5k / marathon / weekly training load)
08:20 – Melbourne Open result: ~1:00 (with extra lap) + what improved
10:08 – Wall balls: technique, volume, and going unbroken
15:43 – Sled push/pull: training heavy, technique, and fixing blow-ups
18:55 – Running build to ~60km/week + managing shin issues
24:05 – Doubles vs solo: pacing, station load-sharing, and why doubles is fun
29:23 – Training consistency with a full-time job (routine, fueling, sleep)
34:05 – Coaching: self-coached now, thoughts on hiring a coach
37:28 – What’s next: Olympic weightlifting + explosive goals


This is a public episode. If you would like to discuss this with other subscribers or get access to bonus episodes, visit johngetstrong.substack.com