Justin Carrard on Training, HIIT, and Longevity

Welcome to the latest edition of Unlock Longevity, where science meets inspiration to empower healthier, longer lives. I’d like to introduce the first issue in a special series of newsletters that is brought to you in collaboration with the Scientific Committee of Clinique La Prairie. Together, we delve into groundbreaking research and innovations that are shaping the future of healthy aging.

?The Clinique La Prairie Scientific Committee brings together world-renowned researchers and clinicians, whose expertise spans diverse fields such as medicine, nutrition, biochemistry, immunology, genetics, and pharmacology.

?This series takes the form of exclusive interviews between myself and the experts on the Scientific Committee. Through these conversations, we will uncover the cutting-edge science and personal insights driving their pioneering work.

?Our first contributor is Dr. Justin Carrard, a Sport and Exercise Physician and accomplished researcher at the Department of Sport, Exercise and Health at the University of Basel, Switzerland. Dr. Carrard’s research focuses on the metabolic determinants of healthy aging and active living. Passionate about the power of exercise to enhance longevity, treat chronic diseases, and prevent injuries, he brings invaluable insights into topics like lipid metabolism, overtraining, and musculoskeletal health.

?In the coming weeks, you can look forward to an array of enlightening articles that marry the rigor of scientific discovery with practical applications for your health journey.

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Can you give us an overview of the overall benefits of regular physical activity on both physical and mental health?

?Regular physical activity improves physical and mental health globally by strengthening muscles and bones, boosting immune function, reducing the risk of chronic cardiometabolic diseases, and reducing stress, anxiety, and depression while improving mood and cognitive function.

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Why is exercise often said to be "better than medicine" when it comes to promoting long-term health and longevity?

?Exercise is considered one the most potent medicines because it simultaneously acts on different body systems, while drugs usually act on a few specific sites of the body (called receptors).

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How much physical activity should an average person aim for each week to achieve minimum health benefits?

?The World Health Organization recommends that adults aim for a minimum of 150–300 minutes of moderate-intensity aerobic activity or 75–150 minutes of vigorous activity per week, along with strength training exercises twice weekly.

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Are resistance or weight training exercises as important as aerobic exercises? Why?

?Both aerobic (endurance) and strength training are essential and should be done as they act differently on the body. For instance, endurance and strength training tend to reduce blood glucose levels using different (synergic) ways.

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What are some generic but effective exercise tips you can share for beginners?

?Start slow and focus on consistency rather than intensity. Choose activities you enjoy, set realistic goals, incorporate rest days, and gradually increase duration and intensity as your fitness improves.

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What is cardiorespiratory fitness, and why is it considered a critical component of overall health?

?Cardiorespiratory fitness refers to the ability of the lungs, heart, blood vessels and muscles to deliver and use oxygen to produce energy during exercise. This is arguably one of the most potent proxy (markers) we have globally, and the American Heart Association even recommends assessing it as a new vital sign in clinical practice.

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What are the specific benefits of improving cardiorespiratory fitness, particularly as it relates to longevity?

?Improving cardiorespiratory fitness reduces the risk of developing chronic diseases, the mortality linked to specific diseases (e.g. cardiometabolic diseases or cancer) and the global mortality. Ultimately, being fitter enables one to live a longer and healthier life.

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Is there scientific evidence linking regular physical activity to increased lifespan or reduced age-related risks?

?Yes, there is plenty of scientific evidence demonstrating that being regularly physically active leads to a lower risk of developing a chronic disease and dying of such a disease. In addition, unfit people who become fit reduce their risk.

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Why is VO2max such an important metric in assessing fitness levels and longevity?

?VO2max is used to assess cardiorespiratory fitness, and both terms are often used interchangeably. It reflects the body's capacity to uptake, transport, and use oxygen to produce energy to exercise. As written above, it is a crucial global health and longevity marker.

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Can you explain in simple terms how VO2max works and how it reflects a person's health and performance potential?

?VO2max is the maximum amount of oxygen the body uses to produce energy and, therefore, movements. It reflects the ability of the lungs, heart, blood vessels and muscles to deliver and use oxygen to produce energy during exercise.

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Does exercise intensity influence VO2max, and if so, how?

?Regular bouts of high-intensity exercise, for instance, under the form of high-intensity interval training, can lead to a significant improvement of VO2max. On average, VO2max can be increased by 10-20% with adequate training, the rest being genetically determined.

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How does exercise intensity impact mortality and longevity? Is there a "sweet spot" for maximizing benefits without overtraining?

?Following the WHO recommendations regarding physical activity is a safe method to improve one's health and optimize longevity. It has been shown that doing twice as much as the WHO recommendations leads to even more health benefits. However, it is possible to train too much and land in a state of chronic fatigue, which is called either non-functional overreaching or overtraining syndrome. The difference between syndromes lies mainly in the time needed to fully recover, with overtraining syndrome needing months to sometimes even years to recover. However, it is essential to remember that these syndromes remain relatively rare and affect very ambitious sportspeople who train a lot. In our modern societies, most people have the opposite problem, i.e. they don't move enough.

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How would you design the ideal HIIT training session for someone who is relatively healthy but has limited time?

?There is no one-size-fits-all HIIT protocol, but rather general principles to follow. A good start could be to repeat six times 1 minute of intensive exercise with 1 minute of rest in between. With time, the number of repetitions can be increased.

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What should the ultimate goal of a well-structured HIIT program be in terms of health and fitness outcomes?

?The idea of HIIT is to spend more time on the training volume close to the intensity reached at VO2max, thereby optimizing the effect of training in a limited amount of time. The ultimate goal is to improve VO2max, well-being and healthspan.

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Can you explain the difference between active recovery and passive recovery? How do you determine which is more appropriate?

?Whether the recovery should be passive or active in a HIIT session depends on the recovery duration between two intensive bouts. It is usually recommended to do an active recovery for a recovery period longer than 2-3 minutes. This enables maintaining the heart rate at a certain level during the recovery and, therefore, reaching the desired heart rate range during the next intensive bout. On the contrary, short periods of recovery (less than 2 minutes) should instead be passive to give the body time to recover to be ready for the next intensive bout.

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For busy professionals who struggle to find time, can you suggest a 30-minute workout routine that maximizes health benefits while being time-efficient?

?A balanced 30-minute routine could include 5 minutes of dynamic warm-up, 20 minutes alternating between 1-minute high-intensity effort and 1 minute of passive recovery (walking), and 5 minutes of cool-down (low-intensity jogging).

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Is it true that as we age, we need to be more cautious about the intensity of our HIIT workouts?

?As we age, VO2max tends to lower, and it is indeed wise to adapt a HIIT session to the current state of VO2max (or fitness). So, the absolute intensity could be lowered, but the relative intensity in terms of percentage of VO2max would remain relatively similar.

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How much rest or recovery time should there be between HIIT sessions to avoid injury or overtraining, especially for older adults?

?Allow 48 hours of relative rest between HIIT sessions to ensure adequate recovery and reduce the risk of fatigue or injury. With relative rest, it is meant not to train at a high intensity in this period. However, low-intensity training can be done.

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What are your thoughts on hypoxic training (training in reduced oxygen conditions)?

?Hypoxic training can improve endurance and repeated sprint capacity by adapting the body to function with reduced oxygen availability. Still, it should be done cautiously and under supervision, especially for untrained individuals.

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Can you explain what hypoxic training is and how it might benefit someone looking to improve their endurance or health outcomes?

?Hypoxic training involves exercising or living in environments with reduced oxygen availability to enhance physical performance and adaptation. There are two main types of hypoxic training:

?Live High, Train High: Individuals consistently live and train at high altitudes, exposing themselves to low oxygen levels. This approach stimulates the production of red blood cells and haemoglobin, improving oxygen-carrying capacity.

?Live High, Train Low: Participants live at high altitudes to benefit from hypoxic adaptation but train at lower altitudes where oxygen is sufficient to maintain high-intensity performance. This method combines physiological adaptation with optimal training intensity.

?Hypoxic training creates an oxygen deficit, prompting the body to produce more erythropoietin (EPO), stimulating red blood cell production. This increases oxygen delivery to muscles during exercise. It also enhances mitochondrial efficiency, vascular growth, and aerobic capacity.

?While hypoxic training improves endurance, its effectiveness depends on the duration, intensity, and individual's baseline fitness. Elite athletes widely use it, but it requires careful management to avoid fatigue or health risks.

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Are there specific populations or age groups that might benefit more from hypoxic training?

?Athletes preparing for endurance sports or high-altitude events and individuals looking to improve cardiovascular efficiency may benefit most from hypoxic training. There is also growing data showing that some patients (for instance, with obesity) could benefit from hypoxic training.

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For someone who is just starting out or is intimidated by intense exercise, what's a simple, realistic way to get started and build consistency?

?Start with low-intensity activities like walking or light yoga, set small and realistic goals, establish a consistent schedule, and gradually progress as your confidence and stamina build.

The "Unlock Longevity" newsletter is my personal contribution to exploring, but most importantly simplifying and making accessible, the themes, techniques, and strategies related to longevity.

If you believe these insights could benefit your network, feel free to share this article!

This article reflects my personal views and is not intended to replace professional medical advice.