#082 The Science of Vigorous Exercise — Should We Train Hard or Train Long? | Martin Gibala, Ph.D.
Sep 19, 2023
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Martin Gibala, a muscle physiologist and professor, discusses the benefits of high-intensity interval training (HIIT) for cardiovascular health, metabolism, and brain function. He explores the trade-off between duration and intensity of exercise, the role of VO2 max in cardiorespiratory fitness, and the effects of HIIT on mitochondrial biogenesis and fat oxidation. The podcast also covers topics such as muscle fiber types, insulin sensitivity, vilpa as a non-exercise alternative, lactate monitoring, work-to-rest ratios, interval training progression, exercise guidelines, and the skepticism of hypoxic training.
High intensity interval training (HIIT) offers various benefits for overall health and fitness, making it a valuable alternative to remaining sedentary.
Engaging in shorter, intense HIIT sessions can potentially yield similar or greater improvements in VO2 max compared to longer, continuous training at a moderate intensity.
HIIT stimulates the growth of new mitochondria in skeletal muscles, enhancing mitochondrial capacity and fat oxidation during exercise.
Vigorous intermittent lifestyle physical activity (VILPA), incorporating bursts of vigorous activity throughout the day, has potential health benefits and is associated with reduced mortality risks.
Interval training can be tailored to different goals and fitness levels, allowing beginners to start with alternating periods of higher and lower intensity, and experienced individuals to incorporate longer or varied intervals to enhance performance.
While individual health and exercise capacity need to be considered, HIIT can be a valuable option for improving cardiovascular fitness, body composition, and glucose regulation in various populations.
Deep dives
The Power of Options: Achieving Health and Fitness Even on Busy Days
This podcast episode discusses the importance of having options when it comes to maintaining a healthy lifestyle, especially on busy days. It explores the benefits of high intensity interval training (HIIT) compared to lower intensity, but higher volume zone two training. It raises the question of whether spending more time at a vigorous intensity or running slow to run fast is more effective. The episode emphasizes the importance of finding the right intensity distribution that suits individual fitness goals and lifestyles. It also highlights the benefits of HIIT, such as optimizing time, improving cardiovascular health, and potentially enhancing cognitive function.
HIIT and Its Impact on VO2 Max and Cardiovascular Fitness
This section delves into the impact of high intensity interval training (HIIT) on VO2 max, which is a marker of cardiorespiratory fitness. It debates whether engaging in shorter, more intense HIIT sessions can yield similar or even greater improvements in VO2 max compared to longer, continuous training at a moderate intensity. It discusses non-response to moderate intensity exercise and the potential for high intensity exercise to eliminate such non-response. Additionally, it highlights the significance of VO2 max in predicting longevity and cardiovascular health.
The Influence of HIIT on Mitochondrial Capacity and Fat Oxidation
This part focuses on the impact of high intensity interval training (HIIT) on mitochondrial biogenesis and fat oxidation. It explains how HIIT stimulates the growth of new mitochondria in skeletal muscles, leading to improved mitochondrial capacity. It clarifies that fat oxidation during exercise is primarily determined by mitochondrial content. The section challenges the assumption that exercising in the fat burning zone is the only way to enhance fat oxidation and highlights the importance of overall mitochondrial content for fat oxidation capacity.
Exploring Other Benefits and Considerations of High Intensity Exercise
This segment explores additional benefits and considerations of high intensity exercise. It covers topics such as insulin sensitivity, glucose control, and the potential impact of high intensity exercise on autophagy. It also touches on the concept of vigorous intermittent lifestyle physical activity (VILPA), which involves incorporating bursts of vigorous activity throughout daily routines. The section examines the potential health benefits of VILPA and its association with reduced mortality risks. Furthermore, it discusses ongoing research and interventions focused on exercise snacks and the potential impact of short bursts of vigorous exercise throughout the day.
Interval training for different goals
Interval training can be tailored to different goals and fitness levels. For beginners, simply getting out of your comfort zone and alternating periods of higher intensity with lower intensity is a good starting point. For those already accustomed to interval training, incorporating longer intervals at high intensity or varying the work-to-rest ratios can provide different challenges and enhance performance. It's important to listen to your body and adjust the intensity and duration of intervals based on your fitness level.
Different types of interval training
There are different types of interval training, such as Tabata, where you go all-out for 20 seconds and rest for 10 seconds, or longer intervals lasting 3-5 minutes. Each type has its own benefits and challenges. Tabata-style training can provide a time-efficient workout and improve cardiovascular fitness, while longer intervals can enhance VO2 max and provide more continuous endurance training. Choosing the right type depends on individual goals and preferences.
Interval training for different populations
Interval training is not limited to athletes, but can be beneficial for various populations. Studies show that interval training, even in short bursts, can improve cardiovascular fitness, body composition, and glucose regulation. Interval training can be adapted for individuals with different fitness levels and health conditions. It is always recommended to consult with a healthcare professional and adjust the intensity and duration of intervals based on individual health and needs.
Considerations and risks
While interval training can be beneficial, it's important to consider individual health and exercise capacity. Individuals with underlying health conditions or those new to high intensity exercise should start gradually and monitor their response. Vigorous intensity exercise, including interval training, temporarily increases the risk of cardiovascular events during exercise. This risk is higher in de-conditioned individuals or those with existing risk factors. However, the absolute risk of adverse events during exercise remains low compared to staying sedentary. It's important to balance the benefits of interval training with individual health considerations and consult with a healthcare professional if necessary.
Benefits of High-Intensity Interval Training
High-intensity interval training (HIIT) offers numerous benefits for overall health and fitness. It is emphasized that remaining sedentary poses a risk to health, making HIIT a valuable alternative. HIIT is especially beneficial for people who are inactive or have underlying health conditions, as it allows them to gradually increase their intensity. The podcast highlights that certain medical conditions, such as atrial fibrillation and unstable angina, are contraindications for vigorous-intensity exercise. It is recommended to consult a cardiologist before engaging in any form of exercise. The episode also emphasizes the importance of tailoring hit programs to individual needs and capabilities. Additionally, the discussion acknowledges that misconceptions exist around HIIT, such as the belief that it must always be performed at maximum intensity. The importance of reframing HIIT as intervals of varying intensity and duration is stressed to make it more accessible to a wider range of individuals.
Reconciling Risk and Benefits
The risks associated with high-intensity exercise, such as atrial fibrillation and coronary calcification, are acknowledged, and it is stated that further research is needed to fully understand the mechanisms and extent of these risks. While some potential risks exist, the episode points out that individuals who engage in high-intensity exercise still have a lower risk of cardiovascular-related mortality. It is suggested that the risks associated with extreme exercise may arise from factors beyond the exercise itself, such as individual variability and other biological factors. Future research in this area may help reconcile the potential risks and benefits of high-intensity exercise.
Future Directions in HIIT Research
The future of high-intensity interval training (HIIT) research encompasses several key areas. Firstly, the focus is on exploring behavioral strategies that promote physical activity, including brief vigorous exercise, intermittent physical activity, and non-exercise physical activity. This aims to encourage more individuals to engage in any form of physical activity. Secondly, rigorous research design is emphasized, with an emphasis on large-scale randomized clinical trials comparing traditional endurance exercise and interval training, using proper sample size estimation and power calculations. Thirdly, the importance of understanding optimal training methodologies for elite athletes is highlighted, to move beyond individual case studies and toward larger interventional studies. Lastly, technological advancements are expected to play a significant role, with advancements in activity tracking, continuous lactate monitoring, and data analysis for everyday individuals and athletes alike.
Dr. Martin Gibala is a muscle physiologist, professor, and kinesiology department chair at McMaster University in Hamilton, Ontario, Canada. He is best known for pioneering research on the health benefits of high-intensity interval training (HIIT) and his profound understanding of HIIT's physiological mechanisms. He is a co-author of the book "The One-Minute Workout."
In this episode, we discuss:
(00:00) Introduction
(11:00) What is high-intensity training?
(11:53) Zone 2 vs. HIIT for VO2 max — which is better?
(13:22) The vital role of vigorous exercise
(14:40) Why VO2 max matters for longevity
(17:45) Why athletes vs. exercisers benefit from different intensity distributions
(22:09) Measuring maximum heart rate and VO2 max
(30:31) How the heart adapts to HIIT to increase VO2 max
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