This episode explores one of the most debated topics in endurance training: whether athletes should take full rest days or train every day. Drawing from elite athlete examples and recent research, the hosts explain that there’s no single “correct” approach. Instead, recovery depends on training intensity, individual preferences, and lifestyle. They highlight the importance of low-intensity (zone 1) training, the role of the nervous system in recovery, and why many athletes sabotage progress by pushing too hard on easy days. Ultimately, recovery—whether active or complete—is a critical part of performance, not a break from it.

• There is no universal rule: both daily training and scheduled rest days can work.
• Elite athletes follow vastly different recovery strategies—context matters.
• Active recovery (zone 1 movement) can enhance recovery through parasympathetic activation.
• Many athletes train “easy days” too hard, limiting adaptation.
• Zone 1 and Zone 2 training are crucial for building aerobic capacity and heart function.
• Full rest days are especially valuable when fatigued, sick, or mentally drained.
• Recovery is not just physical—it’s also mental and emotional.
• Walking, mobility work, and light movement are highly underrated recovery tools.
• Low-volume athletes may not need full rest days but should manage intensity carefully.
• Consistency and quality of sessions matter more than rigid schedules.

• Ep. 34 Øyvind Sandbakk: The Sc… - Race Ready - Apple Podcasts
• Paul Warloski - Simple Endurance Coaching
• Marjaana Rakai | Nordic Performance Lab

Heart rate variability (HRV) is transforming how endurance athletes approach training by providing real-time insight into recovery and readiness. Instead of following rigid training plans, HRV allows athletes to adapt workouts based on their nervous system state, leading to better performance gains and reduced risk of overtraining. This episode breaks down what HRV actually measures, how it reflects the balance between stress and recovery, and why factors like sleep, stress, and lifestyle play a major role. The discussion also explores practical strategies to improve HRV, when to adjust training intensity, and how to interpret low HRV without overreacting.

1. HRV measures the variation between heartbeats and reflects nervous system balance
2. Higher HRV generally indicates better recovery and readiness to train
3. HRV-guided training leads to better performance gains than static plans
4. Poor sleep is one of the biggest drivers of low HRV
5. One low HRV day → switch to aerobic training
6. Two consecutive low HRV days → consider full rest
7. Chronic low HRV requires looking at the bigger picture (stress, hormones, lifestyle)
8. Aerobic training is the most effective way to improve HRV
9. Strength training is beneficial but should avoid training to exhaustion
10. Consistency and context matter more than single HRV readings

• Why Your HRV Won’t Improve — Daily Reset to Boost Recovery
• Paul Warloski - Simple Endurance Coaching
• Marjaana Rakai | Nordic Performance Lab

In this episode of the Athletes Compass Podcast, the hosts explore the pros and cons of training alone versus training in a group. Recent research suggests that while both approaches can produce similar fitness outcomes, group training may lead to greater improvements in functional performance due to social support and motivation. The discussion highlights psychological drivers like self-efficacy, autonomy, and relatedness, and how they shape training success. The hosts share personal experiences with solo workouts, group sessions, and online communities, ultimately concluding that the optimal approach is often a balance tailored to an athlete’s personality, schedule, and goals.

1. Both solo and group training work – overall fitness improvements can be similar across both approaches.
2. Group training may enhance functional performance such as strength and flexibility due to social motivation.
3. Psychological factors matter – social support boosts self-efficacy and self-regulation, which can improve performance.
4. Autonomy vs relatedness – solo training supports independence, while group sessions provide connection and accountability.
5. Training context matters – competitive athletes may benefit from focused solo sessions, while others thrive in social environments.
6. Groups can push athletes beyond perceived limits, helping them discover untapped strength.
7. Races often require solo resilience, making some independent training essential.
8. A balanced approach (often around 80% solo / 20% group) can combine efficiency with motivation and social benefits.

• Paul Warloski - Simple Endurance Coaching
• Marjaana Rakai | Nordic Performance Lab

In this episode of the Athletes Compass Podcast, the hosts explore Athletica’s new AI Coach, a tool designed to provide personalized training feedback and answer athlete questions based on the science of high-intensity interval training. Built using a retrieval-augmented AI system trained on the HIIT Science textbook and Athletica’s internal knowledge base, the coach analyzes workout data, recovery metrics, and athlete comments to generate contextual advice. The conversation highlights real-world examples of how athletes use the tool to improve pacing strategies, adjust training plans, monitor recovery, and avoid injury. The hosts also discuss how consistent logging of RPE and workout notes strengthens the system over time and share a vision for the future where AI could automatically adjust training plans in real time.

1. Athletica’s AI Coach is powered by RAG AI (Retrieval-Augmented Generation), pulling from the HIIT Science textbook, blogs, and platform knowledge to answer training questions.
2. The system combines scientific knowledge with an athlete’s personal data including power profiles, training load, and recovery metrics.
3. Athletes can ask questions about: recovery status, training intensity distribution, pacing strategies, nutrition for key workouts, strengths and weaknesses in their data.
4. The AI can reference historical training data, even comments written months earlier, to give contextual advice. Example use cases include: deciding workout order (threshold vs endurance), planning pacing strategies for races, adjusting training after illness or injury.
5. Consistency in training and logging feedback (RPE, notes, comments) improves the AI’s ability to give useful recommendations.
6. The current system cannot automatically modify your training calendar, but future versions may include that capability.
7. A strong aerobic base remains essential—relying only on high-intensity sessions can lead to plateaued fitness and reduced recovery capacity.

• Athletica's Architecture
• Paul Warloski - Simple Endurance Coaching
• Marjaana Rakai | Nordic Performance Lab

In this episode of The Athletes Compass, the team sits down with Siren Seiler-Viken—researcher, coach, and emerging voice in Hyrox performance science. From her early years as an elite dancer to national-level distance running and now competitive Hyrox racing, Siren shares how sustainability, intelligent planning, and aerobic development form the foundation of hybrid performance. The conversation explores the physiological demands of Hyrox, why running may be the most overlooked performance driver, how to balance strength and endurance without sabotaging adaptation, and why pacing strategy can make or break your race. Whether you're a competitive athlete or new to hybrid fitness, this episode delivers practical, science-backed insight on building performance that lasts.

1. Running accounts for ~60% (or more) of Hyrox race time — aerobic development is foundational.
2. Wall balls produce the highest physiological strain due to total-body demand + accumulated fatigue.
3. Hyrox is primarily an endurance event with strength elements—not the other way around.
4. Max strength matters—but mostly to raise your ceiling so race loads feel submaximal.
5. Muscle mass can become a liability if it compromises running economy.
6. A pyramidal or polarized endurance approach builds sustainable fitness.
7. Double-threshold training can be effective for advanced athletes when carefully structured.
8. Splitting strength and endurance sessions by 5–6 hours reduces interference effects.
9. Pacing is critical—early overexertion can derail the entire race.
10. Variation in endurance modalities (run, row, ski) supports durability and injury prevention.
11. Hyrox’s appeal lies in accessibility, inclusivity, and standardized global competition.

00:00 – Injury Prevention & Mixing Modalities

02:07 – From Elite Dance to National-Level Running

07:57 – What Is Hyrox? Format & Demands

12:03 – Why Running Determines Hyrox Performance

16:25 – Why Wall Balls Break Athletes

22:13 – Is Max Strength Overrated in Hyrox?

26:25 – Programming: Base Building, Strength & Specificity

52:35 – Double Threshold & Concurrent Training

46:05 – The Rise of Hyrox & Olympic Potential

• Siren Seiler-Viken Coaching
• Paul Warloski - Simple Endurance Coaching
• Marjaana Rakai | Nordic Performance Lab

In this powerful and deeply relatable episode, Jeff Weiss shares how he went from starting his first 10K at age 48 to completing Ironmans, ultra marathons, and chasing the World Marathon Majors in his 60s. Along the way, he unpacks the mental battles behind endurance sport, the value of failure, and why chasing big goals reshapes how we see ourselves. From narrowly missing the cutoff at the legendary Comrades Marathon to discovering resilience through ice baths and yoga, Jeff makes a compelling case that racing isn’t just about fitness — it’s about identity, courage, and choosing a life without regret.

1. You’re never too old to start — progress is possible at any age.
2. Big races build identity and self-belief, not just fitness.
3. Failure can unlock even bigger breakthroughs.
4. Planning your “next goal” prevents post-race emotional crashes.
5. Working with a coach builds confidence, accountability, and consistency.
6. Long races reveal mental weaknesses — and mental strength.
7. Ice baths and endurance racing both train the same muscle: courage.
8. Controlled discomfort in sport builds resilience for life and business.
9. “Do it scared” — fear is natural, but action reduces it.
10. Health span (not just lifespan) should be the real goal of training.

• Paul Warloski - Simple Endurance Coaching
• Marjaana Rakai | Nordic Performance Lab

In this episode of The Athletes Compass, Dr. Paul Laursen and the team break down the science and practical application of the second threshold — also known as LT2, VT2, FTP, or critical power. They explain what physiologically happens when you cross this boundary, why base training is essential before adding threshold work, and how over-unders, tempo sessions, and VO2 max intervals raise performance. The conversation explores common mistakes athletes make (especially doing too much intensity), the role of durability, and how to assess threshold progress without lab testing. If you want to train smarter, improve pacing, and sustainably increase performance, this episode delivers a masterclass in intensity control.

1. LT1 vs LT2: LT1 (aerobic threshold) = top of Zone 2, sustainable “all-day” effort. LT2 (second threshold) = highest sustainable steady-state effort before rapid fatigue.
2. Above LT2: Glycolytic demand increases, lactate accumulates faster, heart rate drifts, and fatigue accelerates.
3. Functional vs Lab Testing: FTP and critical power are practical field markers of LT2. Lab tests measure physiology, but field tests often matter more for performance.
4. Day-to-Day Variation Is Real: Sleep, fueling, equipment, environment, and training phase can significantly affect test results.
5. Base Training First: A strong aerobic base (mitochondrial development) improves tolerance to threshold work and increases fat oxidation capacity.
6. Over-Unders Work Because: They stimulate mitochondrial adaptations by forcing lactate clearance and improving aerobic durability.
7. Intensity Control Matters: Spending more time in the correct zone is more beneficial than constantly pushing the top end.
8. Most Common Mistake: Too much high-intensity work without sufficient aerobic base.
9. Durability Is the Goal: Threshold training should build resilience so performance doesn’t break down late in races.

• Paul Warloski - Simple Endurance Coaching
• Marjaana Rakai - Tired Mom Runs - Where fitness meets motherhood.

In this episode, Dr. Mikki Williden returns to The Athletes Compass to explore the Constrained Energy Model, a concept reshaping how athletes and coaches think about training and fueling. Drawing on the groundbreaking work of Dr. Herman Pontzer, Mikki discusses the biological limits of daily energy expenditure, and why the old model of "more exercise = more calories burned" often backfires, leading to fatigue, weight gain, and hormonal dysfunction. The conversation tackles RED-S, perimenopause, nutrient timing, energy availability, and the limits of tracking tools, all while emphasizing the importance of individual context, intuitive feedback, and informed nutrition.

1. The Constrained Energy Model posits that daily energy expenditure plateaus, even with increased exercise.
2. Energy is redirected from "non-essential" functions like immunity and reproductive health under high training loads.
3. Over-relying on devices or formulas to track calories burned can lead to overfueling, weight gain, or gut issues.
4. RED-S (Relative Energy Deficiency in Sport) can impair hormones, recovery, and bone health, especially in female athletes.
5. Basal metabolic rate (BMR) forms the majority of energy use, but varies with sex, age, lean mass, and training history.
6. Fueling needs are individual: what works for Michael Phelps or Killian Jornet won’t work for everyone.
7. Tools like calorie counters can be helpful for education, but not as rigid frameworks.
8. Protein and strength training are critical, especially for perimenopausal women looking to protect bone and muscle mass.

• Paul Warloski - Simple Endurance Coaching
• Mikkipedia | Dr. Mikki Williden’s podcast, covering topics such as nutrition, fitness, and longevity.
• Marjaana Rakai - Tired Mom Runs - Where fitness meets motherhood.