Remembering Dr. Walter Bortz, the Grandfather of Lifestyle Medicine

“Living longer is active, not passive. You create your own destiny”

These are the wise words of Dr. Walter Bortz II, the former Stanford professor and physician whose pioneering work laid the foundation upon which our Lifestyle Medicine Program now stands. After 93 years, filled with groundbreaking research, influential books, and inspiring athletic achievements, Dr. Bortz peacefully passed away on August 5th.

 “Dr. Bortz is considered the grandfather of lifestyle medicine and was a great mentor for me,” says Michael Fredericson, MD, Director of Stanford Lifestyle Medicine. “He was way before his time and was promoting lifestyle medicine principles to his patients and the greater community before anyone else.”

As one of America’s most distinguished scientific experts on aging and longevity, Dr. Bortz devoted his life to reshaping our perspective on aging and health. He boldly challenged the conventional belief that growing older inevitably leads to frailty and decline, asserting that aging should be regarded as a treatable condition largely caused by disuse. By understanding aging in this way, he advocates for a more proactive approach to maintaining lifelong health and vitality through regular exercise. Practicing what he preached, Dr. Bortz was an avid runner who completed 45 marathons across the world, including the 2013 Boston Marathon at the age of 83. 

His work continues to inspire countless individuals to take charge of their well-being and recognize that they have the power to shape both the quality and duration of their lives. Dr. Bortz wrote several books on this topic, including We Live Too Short and Die Too Long, Dare to be 100, The Roadmap to 100, Living Longer for Dummies, Next Medicine, and Occupy Medicine.

“He was my best friend, best man and best expert on how quality of life trumps quantity of life, and health span is far more important than life span,” said attorney Jack Russo, who was Dr. Bortz’s next-door neighbor, running buddy, and co-advisor to the Stanford Lifestyle Medicine program. “If his philosophy is adopted worldwide, the medical profession will be transformed, as will all of us.”

Click to read more about the life chronology of Dr. Walter Bortz II


By Maya Shetty, BS

Healthy, Easy, and Quick Recipes with Stanford Lifestyle Medicine Experts

Nourishing our bodies with wholesome food is an investment in our health and well-being, but does not need to be expensive or complicated to be effective. In the series, “Healthy, Easy, and Quick Recipes with Stanford Lifestyle Medicine Experts,” Jessica Hope, RN and Rusly Harsono, MD, share simple, efficient, and affordable nutrition tips and recipes.

Stanford Lifestyle Medicine nutrition expert Jessica Hope is a 15-year advocate of plant-based diets who conducts clinical research in nutrition at the Stanford Prevention Research Center and staffs the Humane & Sustainable Food Lab at Stanford Medicine. 

“By creating a simple, thoughtful meal plan, you will be able to minimize food waste, save time, and transform budget-friendly and quick-to-prepare ingredients into a variety of nutritious and delicious meals,” says Hope.

Hope recommends eating nuts and beans as great sources of whole-food protein. While her go-to for nuts are ones that have not been roasted, she recommends having beans either straight from the can or preparing dried beans, which is the more affordable option. “Beans are an amazing whole-food, zero-prep, affordable nutrition source,” says Hope. “For breakfast, I often eat two cups of kidney beans with salt, green peas, or chickpeas with tahini.”

Recipe Ideas for Easy and Inexpensive Meals

Stanford Lifestyle Medicine experts Jessica Hope and Dr. Rusly Harsono share simple recipes containing the whole foods of beans and nuts.

The Stanford Simple Salad


  • Two handfuls of leafy greens 
  • Canned beans (pinto, black, garbanzo, or kidney) as the source of protein
  • A handful of nuts (peanuts, almonds, or cashews) for crunch 
  • Fruit (apples, cherries, or pears) for sweetness

Mix these ingredients together and enjoy!

Jessica’s Sweet Potato and Beans


  • Sweet potato (baked)
  • Black beans with salt (heat up and pour over the sweet potato)
  • A sprinkle of salt 

This recipe makes a delicious, protein- and iron- rich meal that only takes about 5 minutes to prepare (if you bake the potato ahead of time). 


  • Since sweet potatoes keep well in the refrigerator, you can bake a bunch of them at once until they are very soft, then store them for later. 
  • To make your sweet potato even sweeter, swap the beans for natural peanut butter that is free of sugar, preservatives, or added oil. 

The common denominator across all these recipes is that they follow the golden rule to use natural or minimally processed foods and freshly made dishes and meals over ultra-processed products. This golden rule is defined by NOVA, which is a nutritional organization recognised by the Food and Agriculture Organization of the United Nations.

Through the insights of Stanford Lifestyle Medicine experts, Jessica Hope and Dr. Rusly Harsono, we can see that good nutrition does not have to be a complex equation. We hope these simple tips and recipes can be a gateway toward a healthy lifestyle where flavor, nutrition, and simplicity coexist.


By Helena Zhang, BS

Expert Weighs in on Wearable Technology for Sleep: Are They Worth it?

The introduction of wearable technologies has sparked a fascination with personal metrics, particularly when it comes to sleep analysis. Those who have trouble sleeping may think this data could help them sleep however, recent assessments have suggested otherwise.

“These sleep wearables should be used cautiously to avoid misleading conclusions about sleep stages,” says Stanford Lifestyle Medicine sleep expert, Jamie Zeitzer, PhD. “Even if these metrics were accurate, which they aren’t, how much do they matter?”

Dr. Zeitzer says it is crucial to not get too focused on the feedback that wearables provide. “A device’s perception of our sleep quality can greatly influence our own,” says Dr. Zeitzer. “For instance, a device indicating a ‘bad night’s sleep’ can create a perception of fatigue, even if the individual slept soundly. This misperception can lead to feelings of tiredness or even induce insomnia.”

The Importance of REM Sleep

While wearables gather data on all the stages our brain goes through during sleep, one particular sleep stage of interest is rapid-eye movement (REM) sleep due to its positive effects on brain development and learning, regulating emotions and consolidating memories.

 During REM sleep, our brain activity is similar to that of being awake and it is during this stage when most of our dreams occur. Research suggests that getting enough REM sleep may help mitigate potentially negative emotional reactions during the day since REM sleep is associated with a reduction in amygdala reactivity—the area of the brain responsible for anxiety, stress, and fear.

On average, REM sleep constitutes about 20 to 25 percent of our total sleep time. This means that getting 7 to 8 hours of sleep would equal around 90 minutes of REM sleep. The REM stage usually starts 90 minutes after you fall asleep, with each of your REM cycles getting longer throughout the night: the first period typically lasts 10 minutes, with the final one lasting up to an hour. Therefore, because REM increases with each cycle, if you do not sleep for long enough, your body may not get enough REM sleep to feel rested the next morning.

“If you need eight hours of sleep, but only sleep for six hours, not only is that a 25 percent reduction in total sleep, that may translate to 60 or 90 percent of lost REM sleep,” says Dr. Zeitzer.

The Importance of Sleep Timing 

Rather than looking at a wearable device to determine whether we’ve gotten enough sleep, Dr. Zeitzer suggests checking in with ourselves and assessing our fatigue levels.

“Wearables can be misleading, so a better way to assess whether we’ve gotten enough REM sleep, is to see if there are any functional consequences, such as feeling tired or having reduced mental clarity,” says Dr. Zeitzer. 

Instead of focusing on the REM sleep data provided by your wearable, Dr. Zeitzer suggests focusing on sleep timing, i.e. going to bed and waking up at the same time every day. “Quality sleep is highly dependent on consistency in sleep timing,” he says. “Consistent sleep-wake times can keep your circadian rhythm in check, to ensure you get enough quality sleep.”


By Helena Zhang, BS

What Should Athletes Eat to Fuel Peak Performance?

Athletes, driven by the pursuit of peak performance, have been in the spotlight for numerous studies exploring how various dietary patterns optimize performance. Due to the breadth of research and recommendations available, athletes are at a crossroads when determining the best way to fuel their goals. For this reason, our Stanford Lifestyle Medicine team members (Matt Kaufman, MD, Maya Shetty, BS, Michael Fredericson, MD, and Marily Oppezzo, PhD) reviewed the research regarding how popular diets impact athletic performance and well-being. They summarized their findings in a comprehensive research article titled Popular Dietary Trends’ Impact on Athletic Performance: A Critical Analysis Review, which was recently published in the journal Nutrients. Their research focused on six dietary patterns: Mediterranean diet, ketogenic diet, low-carbohydrate diet, plant-based diet, intermittent fasting, and disordered eating. Whether you are an elite athlete or an enthusiastic beginner, keep reading to learn more.

Mediterranean Diet

The Mediterranean diet, rich in whole grains, unsaturated fats, lean proteins, fruits, and vegetables, is consistently associated with improved health and performance for athletes. Research on athletes finds this diet is linked to improved muscle power and endurance, as well as body composition. The low inflammatory index of this diet is also associated with enhanced recovery time.

Ketogenic Diet

The ketogenic diet restricts the consumption of carbohydrates and protein to boost the use of fat as an energy source, thus improving weight loss and potentially athletic performance. While this may help athletes, such as wrestlers, who need to stay within specific weight requirements, the prolonged carbohydrate restriction can negatively affect training performance. Research has shown this restriction can increase baseline heart rates, perceived exertion, and rate of bone loss, harming short and long-term performance. However, research has not found significant decrements in performance for athletes following this diet.

Low-Carbohydrate Diet

People often think that Ketogenic and Low-Carbohydrate diets are the same. A low-carbohydrate diet is less restrictive and does not restrict protein intake in the same way that Ketogenic diets would. Research has found that athletes on this diet have no differences in muscle strength and power compared to athletes following a regular diet. However, notable improvements in sprint times and exhaustion perceptions have been observed. As carbohydrates are restricted, the same detriments on performance found in ketogenic diet research may occur. Studies examining low-carbohydrate diets use extremely variable interventions that are difficult to compare. Thus, more research is needed to determine its specific impact on performance.

Plant-Based Diet

Plant-based diets are also adopted by many athletes due to ethical or health-conscious reasons. Typically, vegetarians and vegans consume less saturated fat, cholesterol, and protein but more fiber and iron than omnivores. Due to the restrictions of vegetarian and vegan diets, following these dietary patterns without proper planning may lead to nutritional deficiencies, such as protein, vitamins B12 and D, iron, zinc, calcium, and iodine. These deficiencies may affect performance, recovery, and bone health. Despite these challenges, research has yet to demonstrate a tangible performance decline in comparison to omnivorous counterparts.

Intermittent Fasting

Intermittent fasting, with its varying protocols, involves limiting the time window for eating during the day. This dietary pattern might not be suitable for athletes given their training schedules or the nutrition to fuel performance. As a result, the potential risks may outweigh the benefits. Limited eating windows may be helpful for weight loss or maintaining a strict weight class, but it can also lead to low energy availability and actually harm performance and overall health. Research studies have found that intermittent fasting impaired athletes’ sprint speed and endurance.

Disordered Eating

The pressure to maintain a low body weight for athletics can lead to restrictive diets or even clinical eating disorders, affecting both physical and mental health. These include anorexia nervosa, bulimia nervosa, binge eating disorder, and orthorexia. Athletes, especially those in aesthetics-focused sports such as gymnastics, dance, and ice skating, have the highest rates of disordered eating and eating disorders. These eating patterns can weaken muscles, cause fatigue, and lead to injuries and complications like anemia and osteoporosis. Restrictive diets like ketogenic, plant-based, or intermittent fasting might appeal to athletes with disordered eating tendencies. Thus, athletes should carefully assess their motivations for diet changes and consult professionals to ensure their nutritional needs are met.


To summarize, the researchers found that the Mediterranean diet has the most benefits for athletes regarding recovery and performance. Low-carbohydrate and ketogenic diets show no harm to athletic performance; however, the non-ketogenic low-carbohydrate diets that emphasize protein intake might be more sustainable for the energy demands of athletics. Vegans and vegetarians are at high risk for nutrient deficiencies, especially in nutrients essential for athletic recovery and muscle maintenance. Intermittent fasting may aid weight loss but could hamper athletic performance in endurance and aerobic sports.  For any dietary intervention, the reasoning for the change should be closely monitored by the athlete and their healthcare team to ensure disordered eating is not a risk. Restricting the type and amount of food an athlete consumes can severely impact performance and overall well-being.

Dr. Matthew Kaufman, the lead author of this review article, emphasizes, “Nutrition and athletic performance are inextricably linked. The Mediterranean diet is abundant in foods that support the high energy demands of athletes and promote recovery. However, no one diet is universally recommended for athletes, and any dietary changes should be done in collaboration with healthcare professionals to ensure maintenance of overall health.”


By Maya Shetty, BS


  1. Kaufman M, Nguyen C, Shetty M, Oppezzo M, Barrack M, Fredericson M. Popular Dietary Trends’ Impact on Athletic Performance: A Critical Analysis Review. Nutrients. 2023 Aug 9;15(16):3511. doi: 10.3390/nu15163511. PMID: 37630702; PMCID: PMC10460072.

Everything You Need to Know About Creatine

A recent analysis done by members of the Stanford Lifestyle Medicine team on how different supplements impact sports performance, highlighted creatine since it has been vastly researched and shown to improve muscle strength.

“What many do not realize is that supplements, like creatine, can be beneficial for more than just professional athletes and bodybuilders,” says Matthew Kaufman, MD, member of the Stanford Lifestyle Medicine Exercise and Movement research team and lead author of “The Impact of Supplements on Sports Performance for the Trained Athlete: A Critical Analysis.”

What is Creatine?

So, what is creatine? Creatine is a natural amino acid that people can gain in their diet with foods high in protein or through supplementation. Mechanistically, creatine supports powerful muscle contractions, which is why it is popular among bodybuilders. After digestion, creatine-phosphate is stored in skeletal muscle until the onset of quick, intense physical activity. Once activity is initiated, it is used to rapidly phosphorylate ADP into ATP, which drives fast-twitch muscle contractions, the primary drivers of quick, forceful exercise movements like weight lifting and sprinting.

According to the analysis, athletes that also depend on fast, powerful movements and mobility, like soccer and basketball players, may also benefit from increasing their creatine intake. Its ability to heighten muscle performance is continuing to be tested and is being used by many to increase the size and strength of their muscles.

“What’s nice about creatine, especially compared to other supplements, is how much it has been studied. It has robust, promising data that shows it can really improve athletic performance and muscle composition,” says Dr. Kaufman. “Plus, it can help muscle growth and performance for all different types of people.”

Creatine Is Not Just for Bodybuilders!

Creatine may also be a good supplement for plant-based athletes. The analysis found evidence that vegetarian athletes improved more than omnivorous athletes with creatine supplementation in terms of muscle power output and lean muscle mass, therefore plant-based athletes could consider supplementation to support their athletic performance.

Creatine is also recommended for older individuals to support muscle sarcopenia. With age, many people experience a loss of muscle vitality, which heightens risk of falling and injury. Research published in the Journal of Clinical Medicine indicates that creatine supplementation may help older adults maintain muscle vitality. It suggests that there could be significant benefits from supplementing their diets with creatine for an “anti-aging” effect for the body.

How Much Creatine Do I Need?

Whether taking creatine supplements for athletic performance or daily functioning, it is important to know what the International Society of Sports Nutrition’s (ISSN) recommended dosing strategy is. Their recommendation begins with all individuals taking 5 grams, four times per day for about a week. This first week is called the loading stage, which helps many people adjust to the supplement before experiencing any physical changes. Next, ISSN recommends maintaining a dose between 3-10 grams daily, depending on one’s initial body size.

People considering taking creatine should be aware of some potential side effects. Studies report the possible side effects of increased water retention and airway sensitivity in elite athletes, the latter suggesting the need for further research on how creatine affects those with asthma. We recommend consulting with your physician ahead of time so they can tailor the ISSN’s dosing recommendations for your specific needs.

Overall, creatine supplementation may be promising for many individuals, bodybuilders or not, looking to improve the power of their muscles.

By Carly Smith, BS, MPH (c)


  1. Kaufman, Matthew W. MD; Roche, Megan MD; Fredericson, Michael MD, FACSM. The Impact of Supplements on Sports Performance for the Trained Athlete: A Critical Analysis. Current Sports Medicine Reports 21(7):p 232-238, July 2022.
  2. Burke DG, Chilibeck PD, Parise G, Candow DG, Mahoney D, Tarnopolsky M. Effect of creatine and weight training on muscle creatine and performance in vegetarians. Med Sci Sports Exerc. 2003;35(11):1946–1955.
  3. Candow DG, Forbes SC, Chilibeck PD, Cornish SM, Antonio J, Kreider RB. Effectiveness of Creatine Supplementation on Aging Muscle and Bone: Focus on Falls Prevention and Inflammation. J Clin Med. 2019 Apr 11;8(4):488.
  4. Kreider RB, Kalman DS, Antonio J, et al. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. J. Int. Soc. Sports Nutr. 2017; 14:18.

The Benefits of HIIT and Other Forms of Interval Training

In an era where time is a precious commodity, individuals are constantly seeking efficient ways to achieve their fitness goals. Amidst this quest, high-intensity interval training (HIIT), which is a type of interval training (IT), has gained popularity among fitness enthusiasts due to its ability to yield significant health benefits in a short amount of time.

“I recommend interval training for people who are busy but still want to get fit, because it gets great results in a fraction of the amount of time compared to more traditional cardio workouts. Interval training can be a powerful tool in a well-rounded fitness plan,” says Anne Friedlander, PhD, exercise physiologist and assistant director of Stanford Lifestyle Medicine.

What is Interval Training?

Interval training (IT) was originally defined in 1973 as “intermittent periods of intense exercise separated by periods of recovery.” HIIT stands for high-intensity interval training, which has become the most popular form of IT in recent years. This back-and-forth between physical effort and rest is effective because it challenges the body without causing total exhaustion. IT can encompass various exercise modalities, including cardio, explosive movements with weights, and bodyweight exercises, as long as the period of intense exercise strenuously stimulates the body.

Despite IT’s recent surge in popularity in the US, European runners in the 1950s commonly used this training method, including long-distance runner Emil Zatopekl from the Czech Republic. Zatopekl’s success in the 1952 Olympics is believed to have ignited the widespread adoption of IT across various sports disciplines.

In 2006, a study conducted by Canadian researcher Martin Gibala sparked enthusiasm for IT to improve fitness, not only among athletes, but for the general population as well. The Gibala paper found that even though study participants trained eight hours less over a two-week period, their IT protocol (four to six, 30-second cycling intervals at supramaximal effort with a four-minute recovery) yielded similar fitness and muscle improvements compared to their moderate intensity continuous training (MICT) protocol (90 to 120 minutes of continuous cycling). Adaptations included better time-trial performance (time to complete a set amount of work on a bike), increased oxidative capacity (ability of muscles to use oxygen), buffering capacity (ability to handle acidity during exercise), and glycogen content (more energy stores in the muscles).

Since this pivotal 2006 study, researchers have studied IT protocols extensively and found, when compared to MICT, participants can elicit the same or greater benefits in mitochondrial density, aerobic capacity, metabolic health, insulin sensitivity, body composition, heart disease progression, and markers of genetic age.

In the last two decades, IT has evolved into various types, such as HIIT and sprint interval training (SIT), which have differences in physiological and psychological responses depending on the duration and intensity of the exercise protocol. Many use the classifications outlined in a 2014 review paper, which defines HIIT as a training protocol that requires “near maximal” effort, eliciting 80 to 100 percent of maximal heart rate (HRmax) or aerobic capacity (VO2max). (A very rough estimate of your max heart rate can be obtained using the formula: 220 – your age.) SIT, on the other hand, is classified as a training protocol that requires “supramaximal” or all-out effort, using at least 100 percent of one’s maximal aerobic capacity.

“No matter what your starting fitness level, adding intensity to your workouts can help you achieve your health and fitness goals,” says Dr. Friedlander, adjunct professor in the Stanford Program in Human Biology. “There are many different protocols out there, but the key element is pushing yourself hard for short bursts of time separated by recovery periods. Those bursts of hard work will jump start beneficial adaptations in your physiology and metabolism.”

What are the Benefits of Interval Training?


Muscle Health

The 2006 Gibala paper was the first to reveal how SIT has nearly the same effects on skeletal muscle adaptations as MICT despite significantly less training time and workload. Additional research has shown that a single session of HIIT or SIT increases mitochondrial biogenesis (the process through which muscle cells increase the number and functional capacity of mitochondria), and repeated sessions lead to overall increases in mitochondrial density. Mitochondrial biogenesis plays a crucial role in energy production, metabolic regulation, and overall cellular health. It is important to have healthy and functioning mitochondria to maintain muscle health and decrease the risk of sarcopenia (age-related muscle loss).

Research suggests, in the short-term, that the intensity and interval nature of HIIT and SIT increases mitochondrial biogenesis more than MICT, even when performed for less time and at an equal or less total amount of work. Therefore, incorporating interval training into your lifelong exercise routine (such as adding short bouts of running to your daily walks) will help improve your short-term, and possibly long-term, muscle function.

Body Composition

A meta-analysis that included individuals of all ages and health statuses found SIT protocols were more time efficient than MICT and HIIT in decreasing body fat.

Another meta-analysis, looking at studies including only overweight individuals, found HIIT protocols were more time efficient than MICT in reducing whole-body fat mass and waist circumference. Here, the researchers found that running protocols were more effective than cycling protocols for decreasing body fat, potentially because running uses more muscles throughout the body, which leads to greater energy expenditure.

Cardiovascular Health

A wealth of research since 2006 has consistently demonstrated that IT provides superior improvements in markers of cardiovascular health, cardiometabolic health, and mitigates the risk of heart disease progression more efficiently compared to MICT.

Cardiorespiratory health: VO2max (the body’s maximum rate of oxygen consumption) is a common indicator of cardiorespiratory health. Individuals with a higher VO2max tend to have better overall physical fitness, improved lung function, stronger heart muscles, and enhanced oxygen delivery to the body’s tissues.

A meta-analysis determined that both HIIT and SIT protocols are more efficient than MICT regarding the improvement of VO2max (cardiorespiratory fitness). One study found that SIT increased VO2max to the same extent as MICT, but in one-fifth of the time.

The duration of intervals may also have an impact on VO2max. A comprehensive meta-analysis revealed that IT protocols with longer intervals of intensity (three-to-five minutes) yielded greater improvements in VO2max compared to shorter interval protocols performed for the same total amount of time.

Cardiometabolic health: Interval training is also a powerful tool for improving markers of cardiometabolic health, such as insulin sensitivity and insulin resistance.

A meta-analysis found a variety of IT protocols were superior to MICT in improving insulin resistance, lowering blood glucose levels, and decreasing body weight. The analysis examined various IT protocols, including HIIT and SIT, with a range of two-to-sixty intervals, durations from four seconds to five minutes, and both maximal and supramaximal intensities. Some studies were conducted in lab settings with stationary bikes or treadmills, while others were outdoors on tracks or trails.

“Although research has confirmed that IT is a more time-efficient method than MICT for improved muscle, cardiorespiratory, and cardiometabolic health in the short-term, more research is needed to confirm that those superior benefits continue in the long-term,” says Dr. Friedlander. “As with many aspects of life, balance is key.  Therefore, integrating IT into a well-rounded fitness plan is probably healthier and more advantageous in the long-term than doing IT as your only training method.”

Brain Health

Research suggests that regular physical activity can mitigate age-related volume loss in brain regions associated with memory by improving blood flow to the brain and increasing the maintenance and production of neurons.

One study suggests that intense exercise, like HIIT and SIT, can enhance memory in older adults more effectively than MICT protocols. Participants in this study underwent a HIIT protocol, which included four-minute intervals of running on a five percent incline, interspersed with three-minute recovery periods of walking. They performed this protocol three times per week for a total of 12 weeks, resulting in improved memory performance significantly more than MICT or stretching protocols.

Another study found that young adults had more memory improvements following HIIT sessions (two-minute intense intervals interspersed with two-minute recovery periods) than MICT training sessions. The underlying mechanisms behind these improvements in memory are unknown, but the study did find a correlation between memory improvements and the release of blood lactate following exercise.

During exercise, the chemical lactate travels via the bloodstream to the brain and it is hypothesized that lactate promotes the creation of new cells and blood vessels, thus improving brain function. Higher exercise intensity leads to higher lactate production, resulting in increased levels of lactate in the bloodstream.

It has also been hypothesized that exercise induces the release of brain derived neurotrophic factor (BDNF), a protein that plays an essential role in the health and function of our brain cells. BDNF can be thought of as a “brain fertilizer” that helps neurons grow, survive, and communicate with each other.

Research studies have determined the majority of BDNF is produced in the brain, but other parts of the body, such as skeletal muscle and blood vessels, can also produce BDNF when stimulated by exercise. The previous studies in older and younger adults found that both HIIT and MICT protocols increased BDNF in the bloodstream immediately following exercise.

“Whether your goals relate to health, performance, or body composition changes, research has shown time and time again that IT protocols provide a time efficient way to target those goals,” says Dr. Friedlander. “However, you shouldn’t do IT every day as the intense nature of the activity requires sufficient recovery time, so as not to wear yourself down.”

Types of Interval Training Workouts

Since it is not recommended to do IT every day, one can integrate one of the following IT workouts a couple of times into their weekly exercise regimen.

Here are a few IT training methods that can be modified to any fitness level:

Martin Gibala General Recommendations: Gibala, one of the most notable IT researchers, recommends three sessions of HIIT or SIT exercise per week. Intervals should be between one and four minutes and the entire workout, including rest, should be between 20 to 30 minutes.

Fartlek: Fartlek is a running training method that involves alternating between faster-paced running and slower recovery periods, which can be at an easy or moderate pace. Fartlek training is flexible and can be adjusted based on the terrain, fitness level, and desired outcomes.

Tabata: Tabata involves 20 seconds of all-out intense exercise followed by 10 seconds of rest, repeated for a total of eight rounds (four minutes total). Tabata workouts can be customized for various training modalities that include stationary bikes, sprints, or body weight exercises.

4×4 Interval Training: In 4×4 IT, one performs four sets of intense intervals, with each set consisting of a four-minute, high-intensity exercise followed by a three-minute recovery period. This protocol should last a total of 28 minutes with each set lasting seven minutes (four minutes of activity and three minutes of recovery).

10-20-30: 10-20-30 training involves intervals of an aerobic exercise that alternates interval times. The workout consists of repeating cycles of 30 seconds of low-intensity exercise, followed by 20 seconds of moderate-intensity exercise, and finally, 10 seconds of high-intensity exercise. This pattern is repeated for several intervals, typically for a total of four to five minutes. 

“Whatever your fitness level, incorporating safe and balanced interval training into your exercise routine can improve several aspects of your health and fitness.  This is even true as we get older,” says Dr. Friedlander. “As we age, we tend to stay in our comfort zones, but sometimes it is good to push ourselves to keep our maximum capacity higher. This allows all of our other activities of daily life to feel easier. It can help us live life to the fullest into our later years.”


“If you’re new to interval training, start by adding a few bursts of running or hill climbing into your daily walk or find the stairs in your building at work and do three rounds of vigorously climbing while slowing descending them,” says Dr. Friedlander. “Regardless of your age or fitness level, we encourage you to embrace the challenge of IT and experience its whole-body health benefits!”


By Maya Shetty, BS

Enhancing Health and Speed in Female Distance Runners Through Improved Diet

A groundbreaking nutrition study for female collegiate runners was recently published by Professor  Michael Fredericson, MD, Stanford Lifestyle Medicine (SLM) Director, and Megan Roche, MD, member of the SLM Movement & Exercise pillar. The study’s goals were to improve the health of these runners through a diet intervention, decrease the incidence of bone stress injuries (aka stress fractures), and ultimately improve their performance.

“A runner’s diet is extremely important for maintaining overall health,” says Dr. Fredericson, who has served as the Stanford University track team head physician for decades. “Runners who are excessively lean are prone to injuries, infectious diseases, mental health problems, and loss in bone density.”

The study followed 78 female long-distance runners at both Stanford and UCLA. Over a four year period, the athletes were educated on caloric and balanced nutrient intake, with regular presentations by dieticians and individualized consultations. Athletes with nutrition deficiencies, irregular menstruation, or injuries had more frequent meetings with dieticians. Throughout the study, incidence of bone stress injuries were tracked in the participating athletes.

The nutrition counseling resulted in a remarkable 50 percent reduction in bone stress injuries and doubled the occurrence of regular menstruation among athletes, indicating improved overall health. Even though bone stress injuries affect runners of both genders, there is a higher prevalence among females, which is why the study focused specifically on female distance runners. While the reasons for these findings remain unclear, factors such as male bone density and potential protective effects of testosterone might contribute to the observed gender discrepancy.

In addition to these improvements in health, the nutrition counseling intervention also enhanced athletic performance. Athletes who regained their menstrual cycles and achieved higher bone density also demonstrated enhanced athletic capabilities.

“Your strongest self is your fastest self,” says the second researcher of the study, Dr. Roche, who is an ultrarunner and running coach. “The idea that a leaner body makes for a faster stride is common among distance runners. But it’s inaccurate and sets a dangerous ideal.”

Crucial to the success of the study was shifting the team’s mindset on nutrition and weight. At Stanford University, the coaches and dieticians for the  women’s track and cross-country teams, who were actively involved in the study, played a significant role in fostering a positive perspective on nutrition among the athletes.

Dr. Fredericson and Dr. Roche hope that athletes from every sport, age, and gender can learn from this study. Here is their advice for all athletes:

  1. Eat enough to maintain a healthy weight, which varies from athlete to athlete.
  2. Replenish within 30 minutes after a workout, ideally with carbohydrates and protein.
  3. Consume four to five frequent smaller meals throughout day, rather than three larger meals.
  4. Don’t shy away from healthy, plant-derived fats, like nuts and avocados.
  5. Remember to get enough calcium and Vitamin D for bone strength.


By Maya Shetty, BS

Practice of the Month: HIIT Workouts for All Levels

High-Intensity Interval Training (HIIT) is an intense workout that effectively boosts aerobic capacity and overall health in a shorter amount of time than traditional workouts. 

Former pro-athlete, celebrity trainer, and founder of Platinum Fitness, Peter Park, recommends HIIT workouts for his clients at every fitness level. He suggests one-to-two HIIT workouts per week, in addition to three-to-four days of low-intensity cardio exercise, such as walking or biking for 20 minutes to an hour. 

“Cardio workouts build endurance while HIIT builds muscle strength and higher-end aerobic capacity,” says Park, author of Foundation Training: Redefine Your Core, Conquer Back Pain, Move With Confidence and Rebound: Regain Strength, Move Effortlessly, Live Without Limits.

HIIT Routine

Park has 23 years of experience training elite athletes and has designed the following HIIT routine:

Warm up: Perform five reps of the exercises in the graphic at a slow and controlled pace, modifying as needed, and repeat.

Main set: Perform eight reps of the exercises at a faster pace with minimal rest between each exercise, then take a 45-second rest. Repeat with nine reps, then 10 reps for a total of three cycles.

Exercise Details:

  1. Body weight squats: Perform squats to parallel while extending your arms fully as you descend. Ensure you engage your core and maintain proper posture throughout the movement. Aim for a complete range of motion, focusing on squeezing your quads, core, and glutes at the top of each repetition. Maintain a steady tempo while staying in control.
    • Modification: Sit in a chair and stand back up.
  2. Push-ups: Keep your core engaged and maintain proper posture while performing push-ups. Maintain a controlled tempo and form.
    • Modification: Perform the push-ups on your knees, or against a wall or table.
  3. Jumping jacks: Stay smooth and controlled throughout the movement.
    • Modification: Stand with your feet hip-width apart and perform the jumping jack movement with your arms only.
  4. Stand-ups (aka Burpees): Begin by lying on your stomach on the floor with your hands at chest level. Jump your feet forward, contracting your abdominals, and stand up quickly. Return to the lying position and repeat the process.
    • Modification: Press hands into floor and step back into a high plank position, then step forward and return to a standing position.

Tips for HIIT at Every Fitness Level

Beginner: For individuals just starting out, focus on incorporating intense periods of exercise lasting at least one minute into one’s regular training routine. For example, one could speed up sections of a morning walk or finish a workout with a burst of all-out effort. Don’t worry if you become breathless and have trouble speaking – this is how you’re building your aerobic capacity!

Intermediate: Individuals who already participate in regular exercise but are relatively new to HIIT should focus on incorporating two-to-three HIIT workouts per week into their regular exercise regime. Any exercise modality can be turned into an IT protocol as long as one can push themselves into near maximal or maximal exertion. To optimize benefits, research suggests higher intensities and longer intervals are best. 

Advanced: In well-trained individuals, intense exercise is necessary to generate additional improvements in exercise performance and overall health. To achieve these benefits, extremely high-intensity sprint interval training (SIT) or long-interval HIIT at least three times per week may be necessary. 

Important Considerations

Prepare your body before engaging in HIIT: The intense nature of HIIT can be problematic for individuals with weaker musculoskeletal systems or chronic health issues. Additionally, healthy individuals unfamiliar with this workout type also risk injury. So, remember to build up your capacity for this workout by gradually incorporating periods of higher intensity into your regular exercise routine.

“Pushing your body to its physiological limits without proper training can lead to injuries, compromising your overall health and performance,” says Park. 

Don’t perform interval training every day: While it may be enticing to engage in HIIT daily due to its wide-ranging benefits, this workout can strain the body and hinder physical adaptations when performed too frequently. Instead, opt for one-to-two HIIT sessions per week and mix them with low-intensity activities such as walking or yoga for active recovery. 

Have fun: While incorporating HIIT into your exercise regimen, remember to prioritize your safety and comfort, but also do your best to make it enjoyable so that you stick with it. “HIIT workouts are much more fun with a training partner, says Park. “So, grab your spouse, friend, or co-worker and help each other get out of your comfort zone!”


By Peter Park, CSCS, BS & Maya Shetty, BS