Sally Science @sally_science1 Twitter profile

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Sally Science

@sally_science1

9 months

"Sally, can we use higher tempo strength workouts to improve our aerobic fitness? E.g. Using kettlebell swings or loaded carries with higher heart rates to get our aerobic time for the week?" 👇

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Sally Science

@sally_science1

8 months

"Sally, don't we need high intensity training to train our lactate transporters?" 👇 Lactate transporters, primarily from the monocarboxylate transporter (MCT) family, are integral to the process of lactate shuttling within the body.

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Sally Science

@sally_science1

8 months

"Sally, why is it important to have a big heart 🫀 (i.e. a large cardiac stroke volume)?" 👇 The cardiac stroke volume is a crucial measure in cardiovascular health. It refers to the amount of blood your heart pumps out of the left ventricle with each beat...

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Sally Science

@sally_science1

9 months

"Sally, I read that fat intake is inflammatory, but I also read that increasing fat intake (and reducing carb intake) is a key aspect of metabolic health. How do I reconcile these two?" 👇

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Sally Science

@sally_science1

7 months

"Can you please explain the relationship between Ventilation and VO2?" 👇

Dione

@whennotcycling

7 months

@Alan_Couzens @mclxy7 Can you please explain ventilation rates and how they relate to VO2?

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Sally Science

@sally_science1

9 months

Success is largely about showing up... healthy! "Injuries and illnesses, and their influence on training availability, during preparation are major determinants of an athlete's chance of performance goal success or failure at the international level." 👇

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Sally Science

@sally_science1

9 months

Sally, wondering if you can explain a bit more about how carb ingestion “shuts down” #FatOxidation ? I get that carb utilization will be preferred when ample substrate is available but I always understood there was a mix of substrate used. Different in males/females? 👇

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Sally Science

@sally_science1

10 months

*** How much work is required? *** I obtained access to @alan_couzens database to determine typical daily energy expenditures for each level of athlete.

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Sally Science

@sally_science1

9 months

"Sally, your last tweet on muscle fiber types was interesting. How can I know my own muscle fiber type (% Fast Twitch vs Slow Twitch)? Thanks!" 👇1/17

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Sally Science

@sally_science1

9 months

Despite his low #HRV today, @alan_couzens has been kind enough to provide us with heart rate variability (HRV) data from his "bad" HRV test today & his "good" one yesterday, allowing us to compare instances of his typical HRV against those from a day when his HRV is notably lower

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Sally Science

@sally_science1

9 months

*** Sally, if you burn more carbs during exercise, will you burn more fat at rest? *** 👇 The notion that burning more carbohydrates during exercise leads to increased fat burning at rest is an oversimplification and does not always hold true.

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Sally Science

@sally_science1

9 months

"Sally, this is scary! When he says 'regular, aerobic exercise', what specifically are we talking about? What do I need to do to avoid this?" 👇

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Sally Science

@sally_science1

9 months

*** Important new study shows what athletes want when it comes to mitochondria *** 👇 This study investigates how the fitness level (training status) and sex of individuals relate to the effectiveness of their muscle mitochondria.

Skeletal muscle mitochondria demonstrate similar respiration per cristae surface area independent...

Abstract figure legend Oxidative phosphorylation (OXPHOS) is the mitochondrial process by which ATP is produced. In human skeletal muscle, alterations in the mass-specific capacity of OXPHOS can...

physoc.onlinelibrary.wiley.com

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Sally Science

@sally_science1

9 months

This demonstrates that the high heart rates observed were not primarily a response to the metabolic requirement for oxygen but were likely influenced by the sympathetic nervous system activation due to the stress of the workout.

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Sally Science

@sally_science1

10 months

**Test analysis for lab-rat 🐀, oops, I mean subject, Alan Couzens, January 3, 2024** Based on the provided data, Alan exhibits a VO2max of 4.4 Liters per minute or 53.5 ml/kg/min, which is a measurement of the maximum volume of oxygen he can utilize in one minute per kilogram..

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Sally Science

@sally_science1

9 months

A study by Fernandez in 2015 investigated physiological responses of participants during CrossFit workouts, revealing that while heart rates reached approximately 95% of the participants' maximum, the oxygen demand was relatively low at 29 ml/kg/min.

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Sally Science

@sally_science1

6 months

"Sally, what are typical numbers for VO2max that would place an individual in the top 2.5% for their age and gender?" 👇

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Sally Science

@sally_science1

9 months

It is a common misconception that elevated heart rates during exercise are solely indicative of cardiovascular demand for oxygen. In the context of combining strength and cardio workouts, it's important to understand the cardiovascular responses to different forms of exercise.

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Sally Science

@sally_science1

9 months

"Sally, is metabolic health all about having healthy mitochondria?" As an athlete, you need to understand that metabolic health is a multi-faceted concept that extends beyond just having healthy mitochondria...

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Sally Science

@sally_science1

9 months

Certainly. The scientific evidence supporting the practice of *resonant breathing* in the context of parasympathetic activation is robust. 👇

Dr Jo Hume

@cooolforcats

9 months

@sally_science1 This is super useful advice. Do you have any go-to deep breathing routines?

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Sally Science

@sally_science1

9 months

"Sally, what tests can we use to determine the below?" To determine an athlete's energy needs and carbohydrate metabolism capabilities, a variety of tests can be considered to provide scientific evidence for personalized nutrition and training strategies. 👇

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Sally Science

@sally_science1

8 months

The various heart rate profiles described in the context of a morning Orthostatic Test reveal insights into the cardiovascular system's response to changing posture and possibly into an individual's readiness for physical activity or training load. 👇

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Sally Science

@sally_science1

7 months

An important question from Erin... "How often should we do a lactate test 🩸during the training cycle?" 👇 Lactate testing is a valuable tool for monitoring an athlete's endurance capacity and the effectiveness of their training program....

Erin Green

@EmmaFiji

7 months

@Alan_Couzens Alan, how often do you test? And how often do you recommend athletes test during their season?

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Sally Science

@sally_science1

9 months

However, for optimal cardiovascular health and performance, it's essential to also include pure aerobic exercises such as running, cycling, or swimming. These activities lead to a different cardiac adaptation, mainly an increase in left ventricular chamber size (volume).

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Sally Science

@sally_science1

9 months

Sally, can you please tell me about muscle fiber type and the role that it plays in determining an athlete's best sport and event? 👇

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Sally Science

@sally_science1

8 months

A little more on intensity, fitness and MCT-1 The greater the aerobic capacity of the tissue (i.e. the higher the levels of citrate synthase and the higher the expression of heart-type Lactate Dehydrogenase), the *lower* the intensity needed to increase MCT-1....

Sally Science

@sally_science1

8 months

"Sally, don't we need high intensity training to train our lactate transporters?" 👇 Lactate transporters, primarily from the monocarboxylate transporter (MCT) family, are integral to the process of lactate shuttling within the body.

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Sally Science

@sally_science1

9 months

"Sally, what happens when endurance athletes routinely train at too high of an intensity level for their current fitness?" 👇

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Sally Science

@sally_science1

8 months

Having a larger stroke volume can also mean better oxygen delivery to muscles during exercise, which is obviously a point of interest for an athlete such as yourself.

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Sally Science

@sally_science1

8 months

When assessing economy across different modalities – such as swim, bike, run – several factors have consistently been shown to influence efficiency in translating O2 to movement. These factors can be generally categorized as physiological, biomechanical, and environmental.

Dione

@whennotcycling

8 months

@Alan_Couzens What are the "factors" determining economy in different exercise modalities please, Alan/Sally?

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Sally Science

@sally_science1

8 months

A larger stroke volume often indicates a more efficient heart, as it can deliver a greater volume of blood to the tissues with fewer beats. This can have implications for both your immediate athletic performance and long-term health outcomes.

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Sally Science

@sally_science1

9 months

The balance between a diet that maximizes glycogen resynthesis and one that maximizes fat oxidation is an important but nuanced aspect of sports nutrition. 👇

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Sally Science

@sally_science1

10 months

This study evaluates whether an average recreational athlete is capable of enduring the same level of physical stress as a professional cyclist during a high-intensity event like the Tour de France. 👇

The Tour de France, also possible for mortals? A comparison of a recreational and a World Tour...

Cycling Grand Tours are arguably the epitome of strenuous endurance exercise, and they have been reported to represent the ceiling of sustained energy expenditure for humans. It remains unknown,...

pubmed.ncbi.nlm.nih.gov

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Sally Science

@sally_science1

8 months

This reduced workload for the heart can decrease the wear and tear on the cardiovascular system over time, potentially contributing to a lower risk of heart disease.

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Sally Science

@sally_science1

9 months

Resistance-based exercises, such as kettlebell swings or loaded farmer's carries, certainly increase heart rate and provide a form of cardiovascular stimulus. However, the type of stress exerted on the heart is different from what is experienced during pure aerobic exercise.

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Sally Science

@sally_science1

9 months

In summary, while strength circuit workouts with a high cardiovascular demand may contribute to some level of cardiovascular fitness, they should not replace traditional aerobic training.

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Sally Science

@sally_science1

9 months

Why, for the sake of both your long-term health and your athletic performance, you must avoid falling into the pattern of chronic stress at all costs...👇

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Sally Science

@sally_science1

9 months

Balancing both forms of exercise is crucial to achieve well-rounded cardiovascular fitness and health.

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Sally Science

@sally_science1

10 months

In summary, high levels of athletic fitness require very large energy expenditures. These energy expenditures must be supported with similarly high energy intake as fitness increases.

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Sally Science

@sally_science1

6 months

Men (ml/kg/min): - 20-29: >58 ml/kg/min - 30-39: >57 ml/kg/min - 40-49: >55 ml/kg/min - 50-59: >53 ml/kg/min - 60-69: >50 ml/kg/min - 70-79: >48 ml/kg/min

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Sally Science

@sally_science1

9 months

This eccentric hypertrophy is beneficial as it enables the heart to pump a greater volume of blood with each beat, thus enhancing stroke volume and cardiac output during aerobic efforts.

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Sally Science

@sally_science1

8 months

...sufficient MCT1 to take that lactate that is being produced up and use it as a fuel source. When blood lactates are high for a given effort, it is a good indication that MCT-1 is the limiter & more low-intensity training is required.

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Sally Science

@sally_science1

9 months

This type of stress can lead to a significant cardiovascular response without necessarily indicating effective aerobic conditioning.

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Sally Science

@sally_science1

9 months

"Sally, surely sports is about performance. So, why do we care about individual physiological components like VO2max or lactate threshold or maximal fat oxidation?" 👇

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Sally Science

@sally_science1

8 months

@harry_hardass @christy_cheer @Alan_Couzens Do you remember when.... You spent that time taking lactates for the Aussie swim team and you realized just how much low lactate work the swimmers were doing? And how that this #EasyVolume was what was missing from your own program for all those years?

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Sally Science

@sally_science1

9 months

During high-intensity strength training, the increased blood pressure and vascular resistance lead to afterload on the heart, which over time can favor an increase in the heart wall thickness (hypertrophy of the left ventricular wall).

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Sally Science

@sally_science1

9 months

A busy morning for research! Another significant paper from @gregoiremillet1 and team... This one looking at the impact that a tough multi-day stage race (The #TourDeFrance ) has on a professional cyclist's #HRV 👇

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Sally Science

@sally_science1

8 months

Athletes, through regular, extensive, aerobic training, achieve greater stroke volumes (and lower resting heart rates) as a physiological adaptation. This is an important aspect to consider in your own training and health management.

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Sally Science

@sally_science1

9 months

For athletes, this research underlines the benefits of training not only in increasing the number of mitochondria but also improving their structure, potentially leading to better athletic performance.

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Sally Science

@sally_science1

10 months

- Athletes with a VO2max under 40 ml/kg/min burn on average 362 kcal/day from training - Those with a VO2max between 40-50 ml/kg/min burn approximately 750 kcal/day. - For a VO2max of 50-60 ml/kg/min, the average is 1198 kcal/day.

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Sally Science

@sally_science1

9 months

"Sally, what is 'frame mass' and why is it important for athletes to know their own 'frame mass'?" 👇 Frame mass is a term used to describe the combined mass of the skeleton and the internal organs of the body, exclusive of body fat and muscle mass.

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Sally Science

@sally_science1

10 months

Continued training should aim to maintain or improve these metabolic capabilities, focusing on both volume and intensity to further enhance aerobic capacity, lactate threshold, and metabolic efficiency.

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Sally Science

@sally_science1

9 months

It is this sustained, rhythmic, and whole-body aerobic exercise that is most effective at inducing the appropriate physiological changes needed to improve the capacity of the heart and the vascular system, such as increased chamber size and promoting cardiac compliance.

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Sally Science

@sally_science1

8 months

From a health and longevity perspective, a larger stroke volume is beneficial because it typically results in a lower resting heart rate. When your heart can pump more blood with each beat, it doesn't need to beat as frequently to maintain adequate circulation.

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Sally Science

@sally_science1

9 months

An appropriate balance of fats, sufficient physical activity, avoidance of excessive calorie intake, and a focus on whole foods can all help in achieving better metabolic health and reducing inflammation.

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Sally Science

@sally_science1

10 months

*** Why is #FatOxidation important for endurance athletes? *** Maximizing fat oxidation is important for endurance athletes primarily due to the substantial energy reserves that fat provides compared to carbohydrate stores.

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Sally Science

@sally_science1

10 months

- Athletes with a VO2max over 60 ml/kg/min show the highest average caloric burn at an enormous 1922 kcal/day!

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Sally Science

@sally_science1

8 months

Activities should include long, steady-state, low-intensity cardiovascular exercises, such as running, cycling, and swimming, performed for extended durations.

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Sally Science

@sally_science1

9 months

What this means for you, as an athlete, is that the increased capacity for your muscles to produce energy is likely due to having more mitochondria and denser mitochondrial cristae rather than your mitochondria inherently working better.

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Sally Science

@sally_science1

9 months

If you consume more calories than you expend, regardless of whether those calories come from carbohydrates or fats, you will not lose fat.

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Sally Science

@sally_science1

8 months

**Training MCT-1**: Low intensity endurance training is best suited to upregulate MCT1 expression because it enhances the oxidative capacity of muscle fibers and increases their reliance on lactate as a fuel source.

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Sally Science

@sally_science1

9 months

Scientific evidence strongly supports the link between PNS activation and improved physical recovery, underscoring the importance of such practices for athletes undergoing intensive training and competition phases.

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Sally Science

@sally_science1

10 months

This would indicate that such an athlete would need to consume an additional 1000 kcal per day above their resting needs to compensate for the calories expended during training and maintain their body weight and energy balance, assuming other factors remain constant.

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Sally Science

@sally_science1

10 months

This suggests that with adequate training and nutrition, even non-professional athletes can sustain high levels of activity, similar to the extreme demands faced by professional athletes in endurance events like the Tour de France.

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Sally Science

@sally_science1

9 months

Several factors can affect this relationship, and they include: 1. **Energy Balance**: The key determinant of fat loss is energy balance; one must consume fewer calories than the body expends to lose fat.

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Sally Science

@sally_science1

9 months

A fascinating paper by @JaysonGifford & team on the physiological effects of cycling 16hrs per day for 16 days! Let's dive in... 👇

Physiological assessment of a 16 day, 4385 km ultra‐endurance mountain bike race: A case study

The Tour Divide (TD) is a 4385 km ultra-endurance bicycle race that follows the continental divide from Canada to Mexico. In this case study, we performed a comprehensive molecular and physiological...

physoc.onlinelibrary.wiley.com

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Sally Science

@sally_science1

9 months

As an athlete, it's important to understand how your body utilizes the fuel you provide it, especially during exercise. This study by Jeukendrup et al. (1999) investigated the effects of carbohydrate (CHO) ingestion on glucose production and metabolism during prolonged exercise👇

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Sally Science

@sally_science1

9 months

2. **Exercise Intensity**: High-intensity exercise tends to burn more carbohydrates, while low-intensity activity burns a higher proportion of fat.

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Sally Science

@sally_science1

8 months

**MCT-1** is expressed in many tissues, including red blood cells, heart and oxidative skeletal muscle fibers. It has a higher affinity for lactate, meaning it is effective at transporting lactate at lower concentrations.

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Sally Science

@sally_science1

9 months

However, recent evidence suggests that the relationship between saturated fat intake and cardiovascular disease is not as clear-cut as once thought.

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Sally Science

@sally_science1

10 months

The data indicates a direct correlation between an athlete's VO2max and their caloric expenditure from training activities. VO2max is a measurement of the maximum amount of oxygen an athlete can utilize during intense exercise and is a strong indicator of cardiovascular fitness.

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Sally Science

@sally_science1

8 months

2. **Training MCT4**: Small doses of high-intensity training, at or slightly above the athlete's current maximal lactate steady state can selectively increase MCT-4 expression.

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Sally Science

@sally_science1

9 months

@Alan_Couzens Determining the "fittest" athlete of all time is highly subjective and dependent upon the criteria used to define fitness. Within the scientific community, fitness can be measured in various ways, which typically include cardiovascular endurance, muscle strength, flexibility...

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Sally Science

@sally_science1

9 months

This is an important consideration when discussing nutritional strategies for athletes, particularly in the context of efforts to maximize performance and/or manipulate body composition.

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Sally Science

@sally_science1

8 months

@walter_wise1 @harry_hardass @christy_cheer @Alan_Couzens Do you remember.. When you started tracking training response (fitness/load) and you realized how tightly it was linked to the athlete's HRV and just how important the strength of the body's #Recovery processes is & how pointless loading when HRV is low really is?

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Sally Science

@sally_science1

8 months

@walter_wise1 @harry_hardass @christy_cheer @Alan_Couzens Do you remember.. All of those metabolic tests that you did for top endurance athletes and how you realized very quickly that all of the best athletes had superior fat-burning &, consequently, how important proper #Nutrition is?

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Sally Science

@sally_science1

9 months

In other words, per unit of mitochondrial structure, everyone's muscles were pretty much equally capable of producing energy.

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Sally Science

@sally_science1

9 months

However, high-intensity exercises can increase calorie burn both during and after exercise (EPOC - Excess Post-exercise Oxygen Consumption), which could potentially assist in fat loss *if* it results in a caloric deficit.

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Sally Science

@sally_science1

10 months

The mean daily caloric expenditure for each group ascends with higher levels of VO2max. The data suggests that as athletes' cardiovascular capacities increase, so does the energy they expend during training:

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Sally Science

@sally_science1

8 months

This can lead to improved exercise capacity and endurance, as your muscles receive the oxygen they need to function effectively.

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Sally Science

@sally_science1

9 months

Fat loss is multi-faceted and requires a comprehensive approach that includes managing caloric intake, exercise, nutrition, and lifestyle factors to create a sustainable energy deficit.

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Sally Science

@sally_science1

8 months

lifestyle factors like diet, exercise, and smoking cessation are all significant contributors to overall cardiovascular health and longevity.

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Sally Science

@sally_science1

9 months

Inflammatory responses to saturated fats are variable and may depend on factors such as the presence of obesity, insulin resistance, or the overall inflammatory state of the individual.

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Sally Science

@sally_science1

10 months

For an athlete with a mid-range VO2max of 50 ml/kg/min (considered a moderate level of athletic fitness), the mean daily caloric expenditure from training alone is about 974 kcal. This is averaged across all age groups, with older athletes expending more & younger less.

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Sally Science

@sally_science1

10 months

Based on the data analysis from Alan's database, I categorized athletes into 5 levels according to their VO2max values: under 40 ml/kg/min, 40-50 ml/kg/min, 50-60 ml/kg/min, and 60+ ml/kg/min.

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Sally Science

@sally_science1

9 months

They found that athletes, whether they were runners or cross-country skiers, generally had more mitochondria (by volume) in their muscles and more densely packed cristae compared to people who were untrained or only moderately active.

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Sally Science

@sally_science1

9 months

Some saturated fats, like stearic acid, appear to have a neutral impact on cholesterol, and the context in which these fats are consumed (for example, as part of a diet rich in fiber and whole foods) may mitigate potential negative effects.

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Sally Science

@sally_science1

9 months

This approach will help accumulate a high volume of beneficial heartbeats and promote the flexibility and health of your heart muscle without necessitating high-intensity workouts that are more the domain of elite athletes.

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Sally Science

@sally_science1

10 months

group expends an equivalent of 132% of their BMR. This results in Physical Activity Levels (PALs) *before other incidental activities* ranging from 1.2 to 2.3, with higher PALs indicative of higher levels of physical activity and energy expenditure.

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Sally Science

@sally_science1

10 months

When comparing this caloric expenditure to Basal Metabolic Rate (BMR), which is the number of calories required to keep your body functioning at rest, it appears that the lowest VO2max group is burning an additional 21% of their BMR during training, while the highest VO2max...

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Sally Science

@sally_science1

9 months

Monounsaturated fats, found in high concentrations in foods like olives, avocados, and nuts, have been shown to be beneficial for heart health and may have anti-inflammatory properties.

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Sally Science

@sally_science1

9 months

Individuals with greater metabolic flexibility may switch to burning fats more efficiently post-exercise, while individuals with poor metabolic flexibility will be more susceptible to carbohydrate cravings after exercise.

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Sally Science

@sally_science1

9 months

The notion that dietary fat intake is inherently inflammatory is an oversimplification. The body's response to dietary fat depends on the types of fats consumed, their quantity, the overall dietary context, and an individual's metabolic health.

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Sally Science

@sally_science1

9 months

In conclusion, incorporate regular, low-intensity aerobic exercises, such as brisk walking, into your routine.

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Sally Science

@sally_science1

8 months

This characteristic makes MCT-1 particularly important for the uptake of lactate by the heart and oxidative fibers, where lactate can be used as a fuel source.

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Sally Science

@sally_science1

8 months

Specifically, they found a 2% increase in all-cause mortality for every beat above 45bpm!

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Sally Science

@sally_science1

9 months

The PNS, when operating efficiently, is responsive to blood pressure variances tied to regular breathing. Inhalation triggers a diminished thoracic pressure that activates the sympathetic nervous system to sustain blood pressure.

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Sally Science

@sally_science1

9 months

Certainly, it's important to understand that dietary fats are a diverse group of molecules with different characteristics and effects on the body.

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Sally Science

@sally_science1

9 months

Perhaps most importantly, athletes and coaches should recognize that both extreme efforts and minimal efforts may not lead to fitness improvement. Rather, there is likely a "sweet spot" of load that leads to the most productive (and healthy) outcomes.

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Sally Science

@sally_science1

9 months

3. **Nutritional Status**: Your dietary intake influences substrate utilization during and after exercise. For example, a diet high in carbohydrates can lead to a preferential use of carbohydrates for fuel...

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Sally Science

@sally_science1

8 months

It does little good to have the MCT-4 to shuttle lactate out of the fast-twitch fibers id the athlete doesn't also have the MCT-1 to take that lactate from the blood to be used as a fuel source by the slow-twitch fibers.

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