
Critical Oxygen
We teach athletes and coaches how to optimize their physiology and maximize their endurance potential! By speaking to experts with backgrounds in research, coaching, nutrition, and physiological testing we bring the science of endurance sport success directly to you in an applied way!
Latest episodes

Mar 28, 2024 • 1h 5min
How our Bodies Adapt to Exercise (Signaling Mechanisms) | #44 ft. Dr. Robert A. Jacobs
In this episode of the Critical Oxygen podcast, Dr. Robert Jacobs and I discuss how our bodies adapt to exercise. We explore the various cellular disturbances that are sensed by specific sensors and translate into intracellular signaling cascades that drive adaptation. The key themes covered include the importance of stress and adaptation, the specificity of exercise adaptations, energetic and mechanical signals, redox balance, decreased partial pressure of oxygen, mechanical tension, and extracellular signals. This conversation explores the signaling effects of various molecules and stimuli on muscle adaptation and overall health.
Primary papers of discussion - https://pubmed.ncbi.nlm.nih.gov/23395166/
https://pubmed.ncbi.nlm.nih.gov/36395350/
TAKEAWAYS
1) Exercise imposes stress on the body, which leads to adaptations.
The type and intensity of exercise determine the specific adaptations that occur.
2) Energetic and mechanical signals, redox balance, decreased partial pressure of oxygen, and mechanical tension are important cellular disturbances that drive adaptation.
3) Extracellular signals, such as hormones and proteins, also play a role in the adaptation process. Myokines, cytokines, and adipokines play important roles in signaling within different tissues.
4) Heat may act as a signaling agent and contribute to muscle and cardiovascular adaptations.
5) Exercise is a transient stress that promotes muscle adaptation.
Disturbing cellular sensors through exercise and other means is important for overall health.
Enjoy!
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If you have a question or topic you want us to address, leave a comment!
Follow Phil on Instagram - https://www.instagram.com/criticalo2
Interested in testing, courses, or other long form content check out the critical oxygen website - https://www.criticaloxygen.com
CHAPTERS
00:00 Introduction
03:09 The Importance of Stress and Adaptation
10:10 Specificity of Exercise Adaptations
17:14 Energetic and Mechanical Signals
21:41 Redox Balance
25:28 Decreased Partial Pressure of Oxygen
31:26 Mechanical Tension
53:17 Extracellular Signals
56:39 Signaling Effects of Myokines and Cytokines
57:34 Heat as a Signaling Agent
58:28 Heat Shock Proteins as a Seventh Stimulus
59:32 Redundancy in Cellular Disturbances
01:00:30 The Importance of Redundancies in Human Robustness
01:01:25 Insulin Signaling and Non-Redundant Hormones
01:02:40 Exercise as a Transient Stress
01:03:30 Disturbing Cellular Sensors for Health

Mar 26, 2024 • 55min
How to Know When to Take a Recovery Day or Down Week? | #43 ft. Aaron Geiser
In this episode of the Critical Oxygen podcast, Coach Aaron Geiser and I discuss the importance of recovery days and down weeks in training. We emphasize the need for individualized approaches and the importance of listening to your body. We also discuss the impact of motivation on performance and the dangers of pushing through lack of motivation. The conversation highlights the benefits of flexibility in training and the importance of adjusting workouts based on athlete response. Overall, the episode provides valuable insights into optimizing training and recovery for athletes.
TAKEAWAYS
1) Recovery days and down weeks are important for optimizing training and performance.
2) Individualized approaches are crucial in determining the timing and implementation of recovery days.
3) Listening to your body and recognizing signs of fatigue and lack of motivation are key in making adjustments to training.
4) Flexibility in routines and workouts can help prevent burnout and improve motivation.
5) Comparing workouts and evaluating progress can provide valuable insights into training effectiveness.
Enjoy!
Enjoying these podcasts? Don't forget to subscribe to get notified when new episodes are released.
If you have a question or topic you want us to address, leave a comment!
Follow Phil on Instagram - https://www.instagram.com/criticalo2
Follow Aaron on Instagram - https://www.instagram.com/triageiser/
CHAPTERS
00:00 Introduction and Setting the Context
01:02 Defining Recovery Days and Down Weeks
02:24 Factors to Consider in Implementing Down Weeks
03:16 Monitoring Athlete Fatigue and Wellness
04:42 The Importance of Individualized Approaches
05:42 Evaluating Progression and Motivation
08:05 The Impact of Motivation on Performance
09:27 Recognizing the Signs of Overtraining
10:24 The Dangers of Pushing Through Lack of Motivation
11:42 The Importance of Flexibility in Training
12:11 The Role of Consistency and Specificity
13:40 Making Adjustments Based on Athlete Response
15:33 The Benefits of Changing Workouts
17:22 Managing Training During Stressful Periods
18:46 The Importance of Flexibility in Routines
19:44 Adapting Training During Life Fluctuations
20:39 The Benefits of Recovery Days and Cold Plunges
21:35 The Timing and Implementation of Recovery Days
26:26 Implementing Rest Days for Triathletes
27:01 The Importance of Recovery Days for Athletes
28:24 Adjusting Rest Days Based on Athlete Needs
29:34 The Importance of Individualized Approaches
30:04 Making Decisions Based on Athlete Response
32:28 The Importance of Listening to Your Body
33:28 The Benefits of Comparing Workouts
35:30 The Importance of Long-Term Progression
36:22 Avoiding the Pitfalls of Overdoing Workouts
37:49 The Benefits of a Positive Trajectory
39:17 The Importance of Progression and Recovery
41:38 The Value of Evaluating Workouts
43:35 The Importance of Individualized Approaches
44:33 The Challenges of Implementing Down Weeks
46:52 The Benefits of Adjusting Workouts in the Moment
48:17 The Importance of Trial and Error in Training
49:17 The Role of Listening to Your Body
52:13 Understanding the Purpose of Workouts
53:12 Finding Guidance in Workouts
54:05 Engaging with the Audience
54:29 Upcoming Opportunities and Services

Mar 21, 2024 • 52min
Are More Carbs Always Better for Running Performance? | #42 ft. Jonah Rosner
In this episode of the Critical Oxygen podcast, hosts Philip Batterson and Jonah Rosner discuss the importance of fueling for running and the optimal carbohydrate intake for endurance athletes. We share our personal experiences with fueling during training and races, emphasizing the need for proper fueling to support performance and recovery. We discuss the recommended carbohydrate intake for different durations of exercise and the potential benefits of higher carbohydrate intake. We also highlight the importance of individualization and practice in finding the right fueling strategy for each athlete. Additionally, we explore the sex differences in carbohydrate intake and the implications for female endurance athletes.
TAKEAWAYS
1) Proper fueling is essential for optimal performance and recovery in endurance athletes.
2) The recommended carbohydrate intake for endurance exercise is typically 30-90 grams per hour, depending on the duration and intensity of the activity.
3) Higher carbohydrate intake, up to 120 grams per hour, may be beneficial for endurance athletes, especially during longer and more intense workouts and races.
4) Individualization and practice are key in finding the right fueling strategy for each athlete.
5) There may be sex differences in carbohydrate intake, with females potentially needing more exogenous carbohydrates compared to males.
If you have a question or topic you want us to address, leave a comment!
Follow Phil on Instagram - https://www.instagram.com/criticalo2
Follow Jonah on Instagram - https://www.instagram.com/rosnerperformance
Interested in testing, courses, or other long form content check out the critical oxygen website - https://www.criticaloxygen.com
CHAPTERS
00:00 Introduction and Recap of the Philly Marathon
04:30 Importance of Fueling for Running
20:10 Carbohydrate Intake Recommendations
32:51 Sex Differences in Carbohydrate Intake
39:01 Modeling the Optimal Carbohydrate Intake for a Sub-Two Hour Marathon
46:11 Lower carbohydrate fueling and performance gaps
47:07 Benefits of strength training for women
48:08 Importance of gaining muscle mass for women
49:07 Strength training and its impact on performance
50:26 Summary and key takeaways

5 snips
Mar 20, 2024 • 21min
Is There Truly a Training "Sweet Spot" (Zone 3 training)? | Fast Physiology #2 ft. Dave Schell
In this episode of Fast Physiology on the Critical Oxygen podcast, I am joined again by Coach Dave Schell where we discuss sweet spot or gray zone training. We start by defining sweet spot training as high zone three to low zone four training, which is has been used to accumulate training stress for time crunched athletes while also improving performance. We explore the history of sweet spot training and its popularity among time-crunched athletes. The conversation also delves into the drawbacks of excessive sweet spot training and the importance of periodization and specificity in training. The episode concludes with key takeaways, emphasizing the need for a balanced approach to training and the importance of individualization.
TAKEAWAYS
1) Sweet spot training is define as below threshold but in the upper portion of Zone 3.
2) It could be useful to improve sport specific efficiency and fitness.
3) Sweet Spot Training is attractive to many time-crunched athletes but it shouldn't be your only training intensity!
4) Cyclists may be able to get away with more sweet spot training, but as a runner be cautious of doing too much zone 3 training!
Enjoying these podcasts, subscribe to get notified when new episodes are released.
If you have a question or topic you want us to address, leave a comment!
Follow Phil on Instagram - https://www.instagram.com/criticalo2
Follow Dave on Instagram - https://www.instagram.com/kaizenendurance/
Interested in Gravel or Mountain Bike Coach? Head to Dave's website - https://www.kaizenendurance.coach/
CHAPTERS
00:00 Introduction
01:13 Definition of Sweet Spot Training
03:12 History of Sweet Spot Training
04:06 Benefits and Drawbacks of Sweet Spot Training
05:59 Gray Zone Training in Running
07:24 The Role of Sweet Spot Training in Race Preparation
09:49 The Relationship Between Fatigue and Physiological Adaptation
11:18 Debate on the Effectiveness of Sweet Spot Training
12:21 The Importance of Volume and Intensity in Training
15:40 The Role of Specificity in Training
18:32 Takeaways

Mar 19, 2024 • 58min
How to Recover Better: Beyond Sleep and Nutrition | #41 ft. Aaron Geiser
In this episode of the Critical Oxygen podcast, Coach Aaron Geiser and I discuss various recovery tactics beyond sleep and nutrition. We explore the benefits of cold plunge therapy, including improved sleep and mental toughness. Heat therapy, such as saunas and hot baths, may also aid in recovery and heat acclimation. Massage therapy and trigger point therapy are effective in releasing tension and improving blood flow. We also explore recovery tactics that help athletes de-stress and increase blood flow to optimize performance.
TAKEAWAYS
1) Recovery tactics beyond sleep and nutrition can aid in faster de-stressing and improved blood flow.
2) Cold plunge therapy can improve sleep, mental toughness, and circulation.
3) Heat therapy, such as saunas and hot baths, can aid in recovery and heat acclimation.
4) Massage therapy and trigger point therapy can release tension and improve blood flow.
5) Recovery tactics should focus on de-stressing and increasing blood flow.
Enjoy!
Enjoying these podcasts? Don't forget to subscribe to get notified when new episodes are released.
If you have a question or topic you want us to address, leave a comment!
Follow Phil on Instagram - https://www.instagram.com/criticalo2
Follow Aaron on Instagram - https://www.instagram.com/triageiser/
OUTLINE
00:00 Introduction
03:04 Moving Beyond Sleep and Nutrition
03:30 Cold Plunge Therapy
09:23 Duration and Benefits of Cold Plunge
13:03 Vasoconstriction and Vasodilation
15:26 Heat Therapy and Heat Acclimation
18:37 Massage Therapy
23:49 Trigger Point Therapy
26:27 Maintenance and Proactive Care
28:48 Identifying and Addressing Muscle Imbalances
31:12 Therapeutic Tools: TheraGun and Cupping
35:44 Shockwave Therapy
43:12 Regenerative Medicine: PRP and Stem Cell Injections
50:16 IV Therapy and Legal Considerations
54:11 Importance of Certified Supplements
55:37 Recovery Tactics for De-stressing and Increasing Blood Flow
56:35 Avoiding Shady Practices and Unfair Advantages
57:03 Engaging with the Audience and Conclusion

Mar 14, 2024 • 1h 13min
How to Grow your Mitochondria with Exercise? | #40 ft. Dr. Robert A. Jacobs
This episode of the Critical Oxygen podcast explores the adaptation of mitochondria to exercise. I am joined by Dr. Robert Jacobs where we discuss topics such as the variability in measurements, challenges of wet lab work, dispelling the myth of mitochondrial biogenesis, different populations of mitochondria, hypertrophy of slow twitch fibers, the role of AI in education, and the importance of search engine optimization in research. This conversation explores the remodeling and functional changes that occur in mitochondria in response to exercise. It discusses how mitochondria adapt by adding folds (cristae) and forming super complexes to improve efficiency and electron transfer.
Primary paper of discussion - https://pubmed.ncbi.nlm.nih.gov/26440213/
TAKEAWAYS
1) Mitochondria adapt to fit the energetic needs of muscle cells, forming a network of reticular channels throughout the muscle.
2) There is variability in measurements such as heart rate and lactate, which should be considered when interpreting results - https://pubmed.ncbi.nlm.nih.gov/36866970/
3) Mitochondrial biogenesis is a myth, as mitochondria actually expand and build upon existing networks to meet energy demands.
4) Mitochondria remodel and undergo functional changes in response to exercise, adding folds and forming super complexes to improve efficiency and electron transfer.
5) Temperature plays a role in mitochondrial adaptations, with mitochondria potentially getting 10-15 degrees hotter than the surrounding cell.
6) Exercise intensity affects mitochondrial adaptations, with high-intensity exercise preferentially increasing mitochondrial function and low-intensity exercise promoting mitochondrial volume.
Enjoy!
Enjoying these podcasts? Don't forget to subscribe to get notified when new episodes are released.
If you have a question or topic you want us to address, leave a comment!
Follow Phil on Instagram - https://www.instagram.com/criticalo2
Interested in testing, courses, or other long form content check out the critical oxygen website - https://www.criticaloxygen.com
OUTLINE
00:00 Introduction to Mitochondria and Muscle Fiber Adaptation
06:14 Variability in Measurements
10:55 Challenges of Wet Lab Work
14:09 Dispelling the Myth of Mitochondrial Biogenesis
26:12 Mitochondrial Adaptation to Exercise
34:07 Different Populations of Mitochondria
36:03 Hypertrophy of Slow Twitch Fibers
46:17 The Role of AI in Education
49:15 The Importance of Search Engine Optimization in Research
50:40 Remodeling and Functional Changes in Mitochondria
57:19 Continual Functional Changes and Expansion
59:16 Mitochondrial Heat Dissipation
01:05:48 Effects of Exercise Intensity on Mitochondrial Adaptations
01:08:41 The Influence of Temperature on Fatigue and Adaptation
01:09:40 Homeostatic Perturbations that Stimulate Adaptation
01:11:31 Closing Remarks

Mar 12, 2024 • 1h 2min
How to Improve your Sleep and Fueling to Recover Better! | #39 ft. Aaron Geiser
In this episode of the Critical Oxygen podcast, Aaron and I discuss the importance of recovery for optimizing athletic performance. We emphasize the role of sleep and nutrition in the recovery process, highlighting the need for adequate sleep duration and quality, as well as sufficient protein intake. We hosts also explore individualized recovery strategies and the use of tools such as cold plunges and saunas. we provide practical tips for creating a bedtime routine and optimizing sleep environment.
TAEKAWAYS
1) Recovery is a crucial aspect of optimizing athletic performance.
2) Adequate sleep duration (at least 7 hours) and quality are essential for effective recovery.
3) Individualized recovery strategies should be implemented based on personal needs and preferences.
4) Proper nutrition, including sufficient protein intake, plays a vital role in the recovery process.
5) Supplementing with whey protein or casein protein can help if you struggle to get enough protein from whole foods.
6) Eating patterns, such as consuming more calories earlier in the day and smaller meals before bedtime, could improve sleep quality.
Enjoying these podcasts? Don't forget to subscribe to get notified when new episodes are released.
If you have a question or topic you want us to address, leave a comment!
Follow Phil on Instagram - https://www.instagram.com/criticalo2
Follow Aaron on Instagram - https://www.instagram.com/triageiser/
OUTLINE
00:00 Introduction to Recovery
03:41 The Importance of Sleep and Nutrition in Recovery
05:03 Individualized Recovery Strategies
07:27 The Impact of Sleep on Recovery
09:22 Using HRV for Training Data
10:49 The Benefits of Optimizing Sleep
12:14 Creating a Bedtime Routine
14:38 The Use of Tools for Sleep Improvement
16:02 Foundational Aspects of Recovery
18:00 The Importance of Light and Temperature
20:25 Creating a Wind-Down Routine
23:12 The Benefits of Cold Plunge and Sauna
26:00 The Impact of Alcohol on Sleep
27:52 The Pitfalls of Sleep Tracking Devices
30:14 The Role of Nutrition in Recovery
33:00 Considerations for Vegetarian and Vegan Athletes
45:00 The Importance of Protein Intake
52:54 Importance of Protein Intake
56:03 Protein Targets and Muscle Protein Synthesis
57:29 Eating Patterns and Sleep Quality
59:06 Next Week: Advanced Tactics for Recovery

Mar 7, 2024 • 1h 15min
Oxygen is the most important molecule for endurance performance! | #38 ft. Dr. Robert A. Jacobs
This episode of the Critical Oxygen podcast explores the importance of oxygen in human performance. Dr. Robert Jacobs and I explore the role of mitochondria in energy production, the transfer of electrons and protons, and the process of ATP synthesis. The relationship between oxygen and other energy systems, such as phosphocreatine and glycolysis, is also discussed. The episode highlights the need for a balance between mitochondrial volume density and contractile proteins, as well as the adaptations that occur with different types of training. The role of mitochondria in fatigue reduction and the benefits of high mitochondrial volume density and function are also explored. This conversation explores the distribution of energy systems within cells, the importance of capillary density and mitochondrial volume density, and the potential benefits of supplementing with creatine for endurance athletes.
TAKEAWAYS
1) Oxygen is the most important molecule for endurance performance and life as we know it.
2) Mitochondria play a crucial role in energy production and the transfer of electrons and protons.
3) Training can lead to adaptations in mitochondrial volume density and function.
4) Developing capillary density and mitochondrial volume density should be a priority for endurance athletes.
5) Supplementing with creatine can aid in recovery and improve strength and some aspects of performance for endurance athletes.Enjoying these podcasts?
Don't forget to subscribe to get notified when new episodes are released.
If you have a question or topic you want us to address, leave a comment!
Follow Phil on Instagram - https://www.instagram.com/criticalo2
Interested in testing, courses, or other long form content check out the critical oxygen website - https://www.criticaloxygen.com
CHAPTERS
00:00 Introduction and Importance of Oxygen
02:19 The Origin Story of Critical Oxygen
03:42 The Role of Mitochondria in Performance
05:11 Understanding the Powerhouse of the Cell
06:05 The Energy Transfer Process
08:28 The Importance of Oxygen as an Electron Acceptor
10:18 The Role of Oxygen in Energy Transfer
11:47 The Majority of Oxygen Utilization during Exercise
12:45 The Electron and Proton Transfer Process
14:44 The Role of Substrates in Energy Production
17:07 Understanding Oxidation and Electron Transfer
20:31 The Electrochemical Gradient and Proton Motive Force
23:03 The Inner Mitochondrial Membrane and Cristae
25:01 ATP Synthesis and the Mechanical Energy of ATP Synthase
27:44 The Role of Phosphocreatine and Glycolysis
35:26 The Relationship Between Oxygen and Energy Systems
38:14 The Optimal Balance of Mitochondria and Contractile Proteins
41:36 The Adaptations from Zone 2 and High-Intensity Interval Training
49:04 The Collective Activation of Energy Systems
52:03 The Role of Mitochondria in Fatigue Reduction
53:53 The Benefits of High Mitochondrial Volume Density and Function
54:50 Distribution of Energy Systems within Cells
57:20 Importance of Capillary Density and Mitochondrial Volume Density
58:16 Supplementing with Creatine
01:00:14 Effects of Creatine on Endurance Performance
01:01:13 Benefits of Creatine for Recovery and Consistency
01:02:11 Additional Benefits of Creatine
01:06:00 Phosphocreatine Pool and Mitochondrial Function
01:07:18 Loss of Phosphocreatine during Exercise
01:09:43 Supplementing with Creatine for Endurance Athletes
01:10:12 Strength Training and Force Output
01:12:56 Oxygen as the Most Important Molecule
01:13:26 Closing Remarks and Call to Action

Mar 6, 2024 • 26min
Bonus: Are you doing Zone 2 incorrectly? | Fast Physiology #1 ft. Dave Schell
In this episode of Fast Physiology on the Critical Oxygen podcast, Dave Schell and I discuss the nuances and importance of zone two training. We start with a quick introduction of our new series - Fast Physiology, which is designed to dispel the myths surrounding training trends. We define zone two training as the intensity necessary to build volume over time and emphasize the importance of perceived effort for practical application. We highlight the role of zone two training in supporting high-intensity work and recovery, as well as its contribution to endurance performance. They also address the misconceptions and limitations of zone two training and stress the significance of consistency in training.
TAKEAWAYS
1) The purpose of Zone 2 training is to build volume and absorb harder training!
2) The upper boundary of Zone 2 is close to your first threshold (LT1, VT1, NIRS BP1, Fatmax).
3)Zone 2 training doesn't always have to be right at first threshold!
4) When adding more training time, for most people it's probably best to add more Zone 2 or Volume.
Enjoying these podcasts, subscribe to get notified when new episodes are released.
If you have a question or topic you want us to address, leave a comment!
Follow Phil on Instagram - https://www.instagram.com/criticalo2
Follow Dave on Instagram - https://www.instagram.com/kaizenendurance/
Interested in Gravel or Mountain Bike Coach? Head to Dave's website - https://www.kaizenendurance.coach/
CHAPTERS
00:00 Introduction and Purpose of the Series
03:17 Defining Zone Two Training
04:43 The Nuances of Zone Two Training
08:05 Perceived Effort and Practical Application
10:25 The Importance of Zone Two Training
14:07 Consistency and Volume in Training
19:20 Zone Two Training and Fatigue Resistance
21:43 The Misconceptions of Zone Two Training
23:08 Summary and Takeaways

Mar 5, 2024 • 54min
How to Maximize Your Base Training | #37 ft. Aaron Geiser
In this episode of the Critical Oxygen podcast, Coach Aaron Geiser and I discuss how to make indoor training fun. We acknowledge the boredom and monotony of indoor training, especially during the off-season, and share strategies to keep it engaging. We emphasize the importance of variation in cadence, elevation, power, and training modes to stimulate the mind and body. We also discuss the significance of monitoring heart rate and power during indoor training and the potential impact of heat accumulation and carbohydrate burning. Overall, we encourage athletes to find ways to stay mentally engaged and make the most of their indoor training sessions.
TAKEAWAYS
1) Varying cadence, elevation, power, and training modes can make indoor training more engaging and enjoyable.
2) Monitoring heart rate and power during indoor training helps athletes stay within their desired training zones and avoid overexertion.
3) Pushing the limits in shorter bouts of training can be beneficial for performance improvement, but caution should be exercised for longer training sessions. Communicate with your coach to understand the purpose of each workout and maximize its benefits.
4) Diversity is key in training to keep it fun and interesting.
5) Implement warm-up and cool-down routines in your indoor training sessions.
Enjoying these podcasts? Don't forget to subscribe to get notified when new episodes are released.
If you have a question or topic you want us to address, leave a comment!
Follow Phil on Instagram - https://www.instagram.com/criticalo2Follow Aaron on Instagram - https://www.instagram.com/triageiser/
CHAPTERS
00:00 Introduction and the Boredom of Indoor Training
07:17 The Challenge of Indoor Training
13:03 Creating Variation in Indoor Training
22:02 Heat Accumulation and Carbohydrate Burning
26:24 Pushing the Limits in Training
27:51 Maximizing the Benefit of Workouts
32:34 Making Cycling Training Fun
37:03 The Value of Treadmill Training
42:01 Making Treadmill Training Enjoyable
46:37 Gait Retraining on the Treadmill
50:03 Implementing Warm-up and Cool-down in Indoor Training
51:58 Progressing and Varying Treadmill Workouts
53:19 Closing Remarks and Call to Action