Category Archives: Exercise

A 7 Minute Workout That Really Works

“Maximum Results With Minimal Investment”. It sounds like a shady late night infomercial, but it’s actually the subtitle of a recentreview article from the American College of Sports Medicine’s Health & Fitness Journal. Titled High Intensity Circuit Training Using Body Weight, it made worldwide headlines, especially after the New York Times picked up on it. It discusses the hot topic of high intensity interval training, which essentially means a very short burst of intense exercise plus quick breaks. So instead of the recommended 150 minutes a week of moderate exercise or 90 minutes of strong exercise, you could spend 15 of HIIT, three times a week — and get similar health benefits. Is it too good to be true?

Let’s step back a minute and review the benefits of exercise. Most guidelines, including those from the U.S. CDC, recommend a combination of aerobic activity and muscle strengthening activity based on extensive research showing strong evidence of exercise lowering risks of early death; coronary heart disease; strokes; high blood pressure; diabetes; colon and breast cancer, among others. Even 90 minutes of moderate exercise lowers your risk of premature death by 20%; more is better but the effects start to tail off after 300 minutes, maxing out at 40% reduction.

But very few of us achieve even 30 minutes a week, much less the 90 or 150 minutes recommended. Physical inactivity is one of the world’s leading risk factors for disease, ranked #6 in the USA and #10 in China. That’s why any research showing benefits with less time committment is crucial for our modern societies, all increasingly less active. HIIT got its first boost in 1996 when a Japanese research team led by Professor Izumi Tabata compared moderate intensity training of 60 minutes versus a 4 minute high intensity training on stationary bikes. The HIIT group not only had a similar increase in aerobic activity but also had a much better improvement in anaerobic activity. One study published in 2011 from the Department of Kinesiology and Health Education, Southern Illinois University tested overweight college students and found that just one 15 minute session of high intensity activity changed their resting energy expenditure (metabolic rate) for 72 hours. This was just as effective as a more routine 35 minute workout. Another study from the Faculty of Medicine, University of New South Wales showed that a 15 minute HIIT workout three times a week, compared to more traditional longer workouts, actually had better outcomes losing total body fat as well as insulin resistance. I consider these latter improvements very significant as diabetes continues to skyrocket right along with obesity in most countries.

When it comes to exercise, I confess I am much more sloth-like than a fitness freak, so I love the idea of a quick fix for health which actually works. I first heard about HIIT last autumn and started to do a 5 minute routine each morning. I went all out for 30 seconds performing as many squat thrusts as I could, then took 10 second breaks, then repeated 10 times for a total of 5 minutes. I confess that I stopped this routine after a month, as I do with most of my ambitions for exercise. But I definitely had felt stronger and more alert during those weeks, and I certainly felt that achy muscle sensation after these sessions. Last week I started this newly publicized 7 minute routine, combining 30 second intervals with circuit training. With circuit training, you rotate your exercises between focused muscle groups, and finishing the entire routine ideally will have covered all muscle groups. You can choose any exercises for HIIT, but one additional benefit of this particular cycle is that you don’t need any weights or machines, just your own body, a wall and a chair. You can perform this anywhere, from your hotel room to your office and home. Here’s an image of the routine, from the original New York Times page:

Each exercise should be done for 30 seconds, with 10 seconds of rest in between, for a total of 7 minutes and 30 seconds. You could also repeat this cycle one of two more times for added benefit. It’s important to take these very short breaks as it increases the healthy metabolic response. You will definitely need help keeping track of these seconds, and I found a wide collection of apps for smartphones and tablets which can be custom set to beep at the correct intervals. Just search your app store for HIIT, Tabata or “interval timer” and take your pick.

The key here is to really push yourself, not take a leisurely pace. In terms of intensity, most of these research papers’ recommendations mention “unpleasant” or “discomforting”. Many papers also mention something called VO2max, which is officially measured using oxygen sensor machines but otherwise generally correlates to 100% of your maximum heart rate. Thus we all should know our maximum heart rate, and fortunately this is easy to calculate. You can find online calculators, otherwise you can do the calculation yourself. The formula for maximum workout heart rate, calculated in a 2001 research paper, = 208 – .7 * age.  For example, I am 45 years old and my maximum heart rate (VO2max) is 208 -.7*45 = 177 beats per minute. If I wanted to reach the 150 minutes a week goal of moderate exercise, my target heart rate for moderate exercise would be 60% of max: 0.6 x 177 = 106 beats per minute. The recommended target for more intense exercise is 80% of max, which for me is 142. I usually get up to this rate with a thirty minute treadmill or elliptical machine workout, and quite honestly it didn’t feel too uncomfortable at all. For the more aggressive HIIT therapy, shooting for 90-100% maximum heart rate works out to 159-177 beats per minute. After I performed the above routine I definitely felt a bit “unpleasant” with a pulse of over 160 — exactly where I should be.

So now I’ve finally run out of excuses for not exercising. I can simply get up 10 minutes earlier each day or just be more efficient in the morning, and perform one or two cycles of this routine, ideally three times a week. Add this to my bicycling to and from my clinic and I can finally hold my head up high when I give my standard lifestyle lecture to my patients.

I think this type of evidence-based exercise research is powerful and certainly has altered my usual speech to patients. I previously would always mention the usual recommended minutes of exercise (150 moderate, 90 intense) but now can make it even more appealing: 15 minutes, three times a week. Certainly this wouldn’t appeal to people who already exercise or play sports. And data is still lacking on the long-term benefits and risk reductions from HIIT. But for the silent majority like myself who do almost no activity, HIIT routines are clearly far better than nothing, and could save millions of lives worldwide.


My New York Times Chinese version is here.

Hate To Exercise? I Have Just The Thing For You

Source: Getty Open Content

We parents worry about our children getting enough exercise — but what about ourselves? Are we all leading by example and also getting enough exercise? Surveys show that most adults both here in China and in countries like the USA don’t get the recommended 150 minutes a week of moderate exercise or 90 minutes of strong exercise. So for those of us (including myself) who rarely exercise, what can we do to correct this?

New research shows that short, intense exercise may be just as good for your health as longer workouts. Literally a 4 to 7 minute workout is helpful! It’s called high intensity interval training, which basically includes 30 seconds of all-out exercise followed by 10 second breaks, repeated up to 15 minutes. It could be something as simple as squat thrusts, but you can look up “7 minute workout” on my website or Google and see other routines. This 7 minute workout got a lot of publicity a few months ago after being published in a research journal. It’s a shortened version of circuit training, where you rotate your exercises between focused muscle groups, and finishing the entire routine ideally will have covered all muscle groups. Trust me, the next day your muscles will be feeling both that anaerobic achiness and aerobic burn!

One additional benefit of this particular 7 minute cycle is that you don’t need any weights or machines — just your own body, a wall and a chair. You could also repeat this cycle one of two more times for added benefit. It’s important to take those 10 second breaks between reps as it increases the healthy metabolic response. You will definitely need help keeping track of these seconds, and I found a wide collection of apps for smartphones and tablets which can be custom set to beep at the correct intervals. Just search your app store for HIIT, Tabata or “interval timer” and take your pick. One website at nicely tracks your 7 minute workout.

The key here for all these HIIT routines is is to really push yourself, not take a leisurely pace. In terms of intensity, most of the research papers’ recommendations mention feeling “unpleasant” or “discomforting” after you finish. Many papers also mention something called VO2max, which generally correlates to 100% of your maximum heart rate. The formula for maximum workout heart rate, calculated in a 2001 research paper, is 208 – .7 * age. You should shoot for at least 80% of your maximum heart rate after finishing your routine.

I think this type of evidence-based exercise research is powerful and certainly has altered my usual speech to patients. I previously would always mention the usual recommended minutes of exercise (150 moderate, 90 intense per week) but now can make it even more appealing: 15 minutes, three times a week. But HIIT definitely isn’t for everyone. I don’t think HIIT would appeal to people who already exercise or play sports. And data is still lacking on the long-term benefits and risk reductions from HIIT. I also don’t think that HIIT is appropriate for most kids — they should be getting their recommended 30 minutes of exercise a day from routine gym glasses and after school activities. But for the silent majority of adults who struggle with exercise or always think they don’t have enough time, HIIT routines could be the perfect solution for you.


This article first appeared in my monthly column in Beijingkids magazine. You can read all my previous Beijingkids articles here. It’s an abridged version of my article about the 7 Minute Workout

Activity Trackers: A Review of Fitbit, Jawbone and Nike

Fitness Trackers: Jawbone UP, Fitbit Flex, Nike Fuelband

My long term readers know that I’m not exactly a fitness fanatic, and my waistline has just jumped over a horrible milestone of over 100 centimeters. (maybe sharing my humiliation will motivate me…) I desperately need inspiration to keep me fitter, and I’m also a tech geek, so I’ve been very excited with the burgeoning quantified self movement. This emphasizes electronic gadgets to track health data, with the goal to encourage you to be more active and live a healthier lifestyle. I recently borrowed a few of these activity trackers from the chief editor of Sports Illustrated’s Chinese version, to help with his upcoming review on them. My wrist was heavy with three popular models: the Fitbit Flex; the Jawbone UP; and the Nike+ Fuelband. Are they worth it, or are they just expensive pedometers? Here’s my review.

(If you’ve never heard of activity trackers before, you may want to read a few reviews first, such as from another doctor at iMedicalApps, or this or this; the New York Times; or follow the blog from Quantified Self.)

Features: all three perform the main function of counting your steps for the day, in varying degrees of success. Some were quite far from each other, but overall I didn’t see any major advantage of any. This begged a larger question from me: is monitoring steps is an accurate surrogate for measuring someone’s health? The good news is that there actually is data showing that pedometers can help; a systematic review of the data published in JAMA in 2007, showed that pedometer use lowered blood pressure and also lowered weight. Both of those are serious health risks in our modern world!

I did find myself trying to reach that magic number of 10,000 steps a day, and pushing more in the evenings to reach that goal — especially with the Nike Fuelband, a clear winner here due to its display showing steps as well as calories and the time.

Regarding other features, all three models also track food and calorie counting, but you have to manually enter every meal, every time. This is definitely a potentially useful feature, but unfortunately it could never be automated too easily. I tried to enter a few meals, especially by syncing with the popular app MyFitnessPal. But I stopped after just a couple days of data entry.

I actually found the sleep tracking features to be the most interesting and useful, especially the Jawbone UP’s easy ability to set up naps and quietly wake you up after a specified time. I really liked this feature for a quick afternoon nap, and its vibrating alarm was much more natural to me than any noisy alarm.

Comfort: I was surprised that all were relatively comfortable, even wearing overnight to take advantage of their sleep tracking (except for the Fuelband, which doesn’t offer this). All are water resistant and worked fine in the shower. In terms of style, I personally prefer something very sedate and small that won’t look silly in my doctor’s coat or in business meetings. I think all are fairly cool this way, especially the Jawbone in black. Perhaps the Fuelband is too thick for me, but it certainly gets attention.

Data Reading: These devices are useless if you can’t access the data in an easy to read manner. Clearly the internet is the key, and all have smartphone apps. While I am happily free of Apple’s ecosystem since last year, I apparently am limiting my app selection via my Android smartphone and tablets. Jawbone’s UP app clearly was the most useful, with outstanding and easy to read graphs on my sleep pattern and steps. Their Trends graphs also are super helpful. The Fitbit app doesn’t look nearly as good, plus I also never got it to sync via Bluetooth. If I can’t set something up easily, I’m not going to use it at all.

Are Chinese Healthier Than Americans?

Temple Of Heaven

During these hot summer evenings, my wife and I love to bike around Beijing’s hutongs. On every street corner and in every park, generations of families, friends and neighbors dance en masse, sing along to a classic tune, and chat away while walking — often backwards. This happens every night in every season — in every town and city across all of China.  Every so often my wife will drag me into that happy group of dancers, my two left feet ruining her graceful moves, but we love the charm and warmth of it all. I already know that whenever I move from China and look back upon my many years here, these moments will stand out.
I mention all this because as an American expat straddling two cultures, I inevitably compare the strengths and weaknesses of each. Of course I confess a bias towards an American viewpoint. But I am perfectly comfortable saying that the average Chinese person is healthier than the average American. And I think Americans could learn a few health tips from China.

Perhaps my readers may find that laughable! But after seven years of observations, I truly feel that it is true. I say this especially since my trip last year back to the east coast of America. It’s no secret that obesity in America is a serious health problem, with the majority overweight and more than one third obese. But last fall I was viscerally struck to see this in person. I kept thinking of the Pixar movie WALL-E, where in the near future mankind becomes so obese that no one walks anymore, spending every hour comfortably in their self-driven hovercraft as robots feed, clothe and bathe them. That’s supposed to be hundreds of years in the future, but Pixar’s gloomy vision of future America certainly seems prescient.

Dancing health china america exerciseIn China, it’s still quite rare to see obese people on the streets. This is changing recently, especially among children as families spoil their little emperors. But in general it’s still not common to be overweight in China. Data from the WHO shows an obesity rate of 32% in the USA and only 6% in China, and an overweight rate of 25% in China but a mind-boggling 69% in the USA. Diet differences are a major factor, but another major reason is that people in China move around a lot more, getting their “exercise” just from everyday routines. Clearly the evening culture plays a major role in this healthy activity. It’s such an ingrained part of Chinese culture that there’s a famous old proverb 饭后百步走,活到九十九 (take a hundred steps after eating, live to be 99).

There’s simply nothing like this social nightlife in America, and it’s a wonderful cultural tradition which I deeply wish we had in America. Even in enlightened and active San Francisco, there may be a few people walking their pets or jogging after dinner, but otherwise our American sidewalks are mostly empty at night. It’s a real shame because such daily activity can dramatically decrease your risk for heart disease, the world’s number one killer. A large 2012 study involving over 400,000 people confirms again that even only 15 minutes a day or 90 minutes a week of moderate exercise can reduce your risk of death by 14% and increase life expectancy by three years. A routine 20 minute brisk walk after dinner automatically gets you to that recommended 150 minutes a week of moderate exercise. Just have your nightly walk plus a daily bike commute and you have no need for that gym membership or that treadmill machine you picked up at a yard sale years ago but never use!

Besides the clear differences in weight and daily activity, the average Chinese person has a much healthier concept of nutrition and wellness than the average American. Many Americans are famously healthy with their fruit smoothies, organic supermarkets and extreme workouts. But that percentage of super healthy Americans is easily outmatched by the much more numerous obese, inactive Americans eating large portions and fast food. There’s a great dichotomy of wellness in America! But in China, I’ve noticed that people both rich and poor, from the countryside and the cities have an equally extensive knowledge about which foods are good for each season, which foods help keep you healthy and which help when you’re sick. Chinese also eat many more vegetable dishes with each meal than in America.

Much of all this involves traditional Chinese medicine concepts of balance, yin and yang, and hot and cold. And while I am skeptical of many of the specific medical claims of TCM, certainly the underlying concept of balance is a very powerful philosophy to underline anyone’s approach not just to their diet choices but their entire life. This ingrained Chinese concept of balance regarding foods is far more successfully integrated into people’s mindsets than the American approach. Americans also use the word balance when discussing a balanced diet, but that discussion clearly has failed to be internalized in the culture. So we tried the food pyramid for a while and that didn’t resonate, and now it’s the “MyPlate” campaign. American magazines and bookshelves are filled with health fads and diets that come and go, while the obesity rate and diabetes cases continue to skyrocket. Clearly all this American chatter about health and wellness is completely failing. There is something fundamentally wrong with our current culture’s lifestyle and philosophy of wellness which is hurtling most citizens backwards.

But what about the sorry state of food safety in China, or the massively polluted air and water? How about how the US towers above China in life expectancy, as well as in the World Happiness Report? How can Chinese men be healthier when over half of them smoke? These are valid counterpoints, but I argue that these are short term problems. Thirty or forty years ago American men smoked just as much as Chinese men, but after public education campaigns the rate is now much lower (but still too high). Regarding happiness, the number one factor is income, and China’s average income is still a small fraction of the average American. And while the World Values Survey also noted more happiness in Americans, more Chinese felt their state of health was good. And with the environment, China is going through the same pattern of self destruction as every other industrialized Western country did — and there’s no reason not to assume it will clean up just as well, in time.

Let’s assume that in a couple decades these obvious environmental and social differences will be improved, along with economic parity. What will we see? Will we see China’s obesity rate also catch up to the west? I think not. Actually, I prefer to think not. I would like to be an idealist and say that even with economic parity, Chinese will still preserve their concepts of wellness and balance, still eat their vegetables even if surrounded by KFC and Starbucks. And I hope more than anything that both American and Chinese streets will be filled at night with singing and dancing.

Diabetes: Yes, You Can Prevent It. Here's The #1 Tip…

Here’s another pop quiz: What’s the most effective way to prevent or reverse diabetes?

  • Exercise
  • Diet
  • Weight Loss
  • Avoiding sugar

The answer, surprising to many, is not diet, it is — weight loss! Losing about 5-10% of your body weight seems to have the most impact in reducing your risk of developing diabetes. In fact, every kilogram of weight loss lowers risk by 16%! This was shown in some good studies, especially an article in 2006 from Diabetes Care, called “Effect of Weight Loss with Lifestyle Intervention on Risk of Diabetes”. This study delved deep into the amazing research from one of public health’s most famous programs, the Diabetes Prevention Program, which studied thousands of pre-diabetics over many years. This program released a world-famous study in 2002 showing that aggressive lifestyle changes reduced a pre-diabetic’s chance of developing full-blown diabetes by an astonishing 58%; this was much more effective than the preventive daily pill, called metformin, which reduced risk 31%.

But this initial study didn’t specifically say which part of lifestyle changes was most effective; was it the weight loss, the increased exercise, or a diet overhaul? We found out the answer from this above 2006 follow-up study, which broke down the 2002 data. The main points:

  • A 5% weight loss reduced risk 58%
  • Second most effective: exercise. Those who met the goal (150 minutes a week of moderate exercise) reduced risk by 44%
  • Third most effective: diet changes, especially reducing daily fat to <25% total daily calories

What this should mean for my readers, especially those who have been told they are pre-diabetic, is that you should focus first on losing at least 5% of your weight. Of course, a major component of weight loss involves more exercise and eating less fat, so it’s all connected. But what the data does mean is that if you only focus on exercise but are still gaining weight, or if you’re cutting fat but still not losing weight, then you need to rethink your action plans.

Other great news: the study also shows that those who achieved all three goals (losing >7% weight; exercising >150 minutes a week, and lowering diet fat <25%) lowered their risk of diabetes by over 80%! The figure below from this 2006 study clearly shows step-by-step lowering of risk with all 3 components; the dashed line shows the risk when weight loss is removed as a factor: as you see, there is still an improvement but not nearly as impressive:

diabetes risk and lifestyle changes
diabetes risk and lifestyle changes

I think this is a great study which really helps clarify people’s wellness plans for lifestyle choices. Now, the major question is — how to lose weight? Well, if I could figure that one out and patent it, I’d be rich. Serious weight loss is extremely hard, perhaps even more difficult than quitting smoking. What we do know is that diets do not work — people who repeatedly diet almost always regain weight plus a bit more. Nope, the simple answer, unfortunately, is that we all need to do the hard work of reevaluating our lifestyle; true and sustained weight loss must include diet changes and routine exercise. Don’t forget the golden rule of 150 minutes a week of heart-racing exercise.

Do You Know How Overweight You May Be?

I created a Body Mass Index (BMI) calculator on a previous post here, where you can see which category you fit: normal, overweight, obese, or morbidly obese.

More Information

The web has tons of information for diabetics, but here are a few detailed patient handouts from the UpToDate Patient Information website:

Patient Info on Diabetes Type 2

Patient Info on Diet and Diabetes

Other good bets would be from or the

What's Your Target Heart Rate for Exercise? Find Out Now…

I often lecture people on exercise, and I frequently mention how 150 minutes a week of “moderate” exercise can be just as healthy as 90 minutes of heavier exercise. But what’s the difference between light, moderate and heavy?

The American College of Sports Medicine (ACSM) defines exercise intensity in three ways: percentage of maximum heart rate, rate of perceived exertion, and METS (metabolic equivalents). This can be confusing, but I think heart rate is the easiest to grasp. The basic points are:

  • Moderate activity is ~60% of maximum heart rate (MHR).
  • “hard” exercise is ~80% MHR, and
  • “very hard” is >90% MHR

How To Find Your Heart Rate

There are a lot of online calculators to help you figure out your target heart rates. Most use the same formula:

Maximum workout heart rate=
(220 – age – resting heart rate) X percent of maximum heart rate + resting heart rate.

For example, a 24-year old with 65 beats per minute resting pulse would have:

Moderate (60% max) goal: (220 – 24 – 65) X .60 + 65 = 144 beats per minute
Heavy (80% max) goal: (220 – 24 – 65) X .80 + 65 = 170 beats per minute

You can quickly find out your max rate and goals at many websites: my favorite is at

Other Formulas: METs

Many articles mention METs, which stands for “metabolic equivalents”. This is a bit too abstract for most, but the general rule of thumb is that moderate exercise = 4-6 METs. So, what is 4 METs? Here’s a nice table describing METs and exercise:

METS Activity
1 resting quietly, watching TV, reading
1.5 eating, writing, desk work, driving, showering
2 light moving, strolling, light housework
3 level walking (2.5 mph), cycling (5.5 mph), bowling, golfing using a cart, heavy housework
4 walking (3 mph), cycling (8 mph), raking leaves, doubles tennis
5 walking (4 mph), cycling (10 mph), ice or roller skating, digging in the garden
6 walking (5 mph), cycling (11 mph), singles tennis, splitting wood, shoveling snow
7 jogging (5 mph), cycling (12 mph), basketball
8 running (5.5 mph), cycling (13 mph), vigorous basketball
9 competitive handball or racquetball
10 running (6 mph)

The Bottom Line

Everyone should figure out what heart rate counts as moderate activity. You need to:

  • first count your resting pulse for one minute;
  • then use an online calculator to see what equals 60% of your max heart rate: that pulse should be your minimum goal during exercise.

Everyone should be striving for at least moderate activity levels, 150 minutes a week. Biking daily as a commute, or brisk walks and dancing, may get some of you there without the need for gym memberships.