How Much Exercise is Enough? How Much is Too Much?

Everyone’s exercise tolerance and fundamental needs are going to be unique, but there are a few things we can generalize. I think there is a minimum that almost everyone will need to meet in order to be metabolically healthy, and also a point at which exercise stops being helpful and becomes harmful. Between those two points is the potential for individualization and experimentation.

How Much Do You Need?

There’s actually been quite a bit of research into the health benefits of exercise and how much exercise is necessary to experience those benefits, and currently it appears that the amount necessary to support metabolic and cardiovascular health is fairly modest. This is good news for people who have a hard time getting motivated or who don’t enjoy it, or who simply don’t have a lot of time. The current, evidence based recommendations that virtually every reputable public health agency have adopted are as follows:

  • 150 minutes a week of moderate intensity exercise (such as hiking or brisk walking)

OR

  • 75 minutes a week of vigorous exercise (such as running or spinning)

AND

  • full body resistance exercises twice a week (such as weight lifting or even yoga. These activities can be included in the 150 or 75 minutes above if they elevate your heart rate adequately).

You can meet these minimums in five 15-30 minute sessions, depending on the intensity you work at. The higher the intensity of your workout, the shorter it can (and really should) be.

For more information on how to determine the intensity of your exercise, check out my ‘Walking for Health and Fitness’ post.

How Much is Too Much?

Determining what is ‘too much’ is much less cut and dry. Clearly there are people (like Ironman Triathletes and Ultra endurance runners) who thrive on large volumes of exercise. But it is possible to exercise too hard, or too much. Overtraining is a real condition, with a pretty well defined set of symptoms, although it can be difficult to diagnose it properly.

The objective symptoms of overtraining include: changes in heart rate response, elevated cortisol after exercise, reduced reaction time and performance, and immune suppression. The subjective symptoms include: changes in mood, sleep disturbances, perception of stress and changes in self perception.

Researches have reached somewhat of a consensus regarding the classification and stages of ‘overtraining’, as follows:

Overtraining‘ is a catch-all term to describe the process of intensified training leading to decreases in performance. The first stage of overtraining is ‘Functional Overreaching‘ in which performance suffers but resolves after adequate rest. ‘Non-functional Overreaching‘ is a decrease in performance and psychological and neuro-endocrinological symptoms that resolve after adequate rest. And ‘Overtraining Syndrome‘ is a longer term decrease in performance (more than 2 months) accompanied by more severe objective and subjective symptoms of overtraining.

Diagnosing

It is important when attempting to diagnose overtraining to rule out other psychological or physiological illnesses that could be producing these symptoms. There are MANY conditions that could be present, from endocrine disorders to nutritional deficiencies to infectious disease to eating disorders. Like other troublesome self-diagnoses (Sugar Addiction, and Adrenal Fatigue for instance) the danger in self-diagnosing and treating is that there may be a real illness present for which inaccurate self-diagnosis hinders appropriate treatment. In my opinion and experience, when a non-athlete is experiencing these symptoms it’s far more likely they’re dealing with a nutritional deficiency or an eating disorder than true overtraining. Getting proper diagnosis and treatment is vital or the problem will only get worse.

Some signs to watch for that could indicate that there could be a physiological, psychological or overtraining problem developing:

  • insomnia
  • anxiety and/or depression
  • changes in self perception
  • fatigue
  • increasing anxiety about and/or attention to your weight or body shape
  • decreases in exercise performance
  • more frequent colds and infections
  • slower recovery after exercise
  • loss of interest in workouts, decrease in enjoyment and sense of accomplishment

Treatment

For the vast majority of people, allowing adequate time between workouts for recovery is all that is necessary to prevent overtraining. Your individual recovery requirements are unique, the best thing you can do is monitor your energy levels and sense of enjoyment during workouts. If you are dreading exercise you used to enjoy and counting the minutes until it is over, or feeling a lack of accomplishment after workouts that used to make you feel awesome, take a few days off, and dial back the intensity of your workouts until your enthusiasm returns.

Who Needs to Stop Exercising

In some cases, complete rest is indicated, but in my opinion these cases are pretty rare. Exercise is so fundamentally important to healthy metabolic function that I think complete rest should be reserved for those who have the clinical symptoms of overtraining,and/or those who are dealing with metabolic adaptations to starvation. People who need to completely stop exercising are sick enough that they need to be under medical supervision anyway. Most people can prevent overtraining from progressing to Overtraining Syndrome by resting adequately between workouts and reducing the intensity of their activity.

If you feel like you’re dealing with something more than a temporary bout of fatigue, or resting doesn’t improve your symptoms, see a doctor. Get a referral to an endocrinologist and/or a therapist, and get tested for the psychological and physiological effects of overtraining. And keep an open mind to the potential that it might not be overtraining, that it might be a psychological issue. Getting an accurate diagnosis and appropriate treatment will ensure you won’t waste time and money treating an illness you don’t have. Follow the advice of your medical professional if you find yourself dealing with these issues. As I said above, self diagnosing, or relying on an internet personality for diagnosis, puts you in danger of not getting appropriate treatment. This is a fairly big problem, as overtraining is a trendy diagnosis these days. These symptoms should not be taken lightly.

Most people will do just fine with regular, moderate activity in the form of walking, cycling, or casual social sports activities and some basic resistance exercises a few times a week. People who enjoy more vigorous forms of exercises will likewise do fine as long as they make sure to give their body proper recovery time and eat enough to support the added demands of their training.

Read More On the Topic:

American Heart Association Activity Recommendations
World Health Organization Activity Recommendations
CDC Activity Recommendations

Diagnostic Tools for Overtraining
Scientific Methods for Diagnosing Overtraining
Early Warnings of Overtraining

Inactivity and Metabolic Health V

It’s time for another installment in my Inactivity and Metabolic Health Series! For your consideration today is the small but interesting study from the Washington University School of Medicine in St. Louis, Missouri:

Improvement in Glucose Tolerance After 1 Wk of Exercise in Patients With Mild NIDDM

There were only 10 middle aged men in this study. While it’s true that studies this small can’t automatically be extrapolated to apply to everyone, what I’m trying to show people through this series is that each small study serves as a data point in a broader constellation of evidence. There is quite a vast body of evidence that inactivity is a primary driver of metabolic dysfunction, and even though no single study can ever be taken of irrefutable evidence of anything, when dozens, hundreds or even thousands of studies all show similar results across population groups, one must sit up and take notice. You can prove pretty much anything if a single study is your litmus test (broccoli will kill you! I saw a study!). What does the weight of evidence say, though?

On to the study. 7 of the men in this study had mild NIDDM (non-insulin dependant diabetes mellitus) and 3 had impaired glucose tolerance (ie, they hadn’t been diagnosed with NIDDM yet but had the precursors). They were instructed not to change their diets over the course of the study, and kept food logs that were analyzed by a dietician to ensure that study results weren’t confounded by diet changes. They were given an initial Oral Glucose Tolerance Test, a physical exam (including blood lipid panel), and a maximal treadmill exercise test before study onset to establish baseline values.

The subjects engaged in a 7 day exercise program consisting of 50-60 minutes on a treadmill or ergometer, working at 60-70% of their maximum heart rate. On the 8th day they were given a second OGTT and exam. On the 9th day they were given a second treadmill test.

Results

VO2 max, body fat percentage and weight all remained unchanged after the 7-day exercise program, so those factors did not confound the results. There was a 36% decrease in plasma glucose, a 32% decrease in plasma insulin concentrations, and a 32% decrease in triglycerides.

What is notable here is that the subjects’ insulin response to a glucose load (from the OGTT) was significantly lower than it had been before the study. What this means: their bodies released less insulin in response to the same amount of sugar after exercising for 7 days. This is significant to the Great Sugar Narrative that holds that sugar is the driver of insulin production and release. Clearly exercise is a pertinent factor here that is ignored by the sugar-causes-diabetes contingent. Exercise can mitigate the insulin response to sugar.

Plasma glucose also decreased, even with a decreased insulin response, which indicates that the cells ability to respond to insulin also improved. From the study:

“The results of this study show that regularly performed vigorous exercise can result in a significant improvement in glucose tolerance in some patients with mild NIDDM. This improvement occurred despite a significantly smaller increase in plasma insulin levels. it appears that the improvement in glucose tolerance was due to a decrease in resistance to insulin.”

Also of note: triglycerides decreased 32% with no change in diet.

Bottom line: exercise reduces insulin response AND makes the body more sensitive to the action of insulin. Exercise does lots of other groovy things too.

Keep moving.

What is Metabolic Health?

I talk about metabolic health a LOT, and it’s a really misunderstood term, so I’m going to very briefly explain what I mean by it.

Here is the definition of metabolism I base my philosophy and recommendations on:

Popular culture has distilled the term ‘metabolism’ down to some variation on ‘how many calories the body burns per day’. Energy expenditure is only one aspect of metabolism though. Metabolism is actually every chemical process of every single cell in your body. When I refer to ‘metabolic health’ what I mean is the function of every cell in your body. Proper cell function produces proper endocrine function, which produces homeostasis and metabolic health.

Exercise, appropriate energy balance, sleep, sunlight and good nutrition all affect your body on a cellular level. Supporting proper cellular function supports health on a systemic level. Our approach to health must be expansive and systemic, and not fixate on only one or two aspects of cellular function. Only when the SYSTEM is healthy is metabolic health achieved.

Melkor Picks up the Baton

I loved this short, and to the point post from Melkor on facebook today:

“If you’re inactive, you probably don’t need much in the way of carbs. But humans aren’t metabolically normal unless they’re active on a regular basis. So the healthy solution isn’t to go low-carb, it’s to increase activity level to the point where you need the carbs”

 

The relationship between metabolic health and exercise is one primary focus of my blog here, so when someone else says so succinctly what I believe is an important and far too often completely and willfully ignored truth, I think its’ worth highlighting.

Low-carb is a band-aid solution to the metabolic dysfunction caused by inactivity. The human body requires regular physical activity to remain metabolically healthy. When the body is metabolically healthy, it can metabolize carbs (and fat and protein) just fine.

Metabolically healthy people do not need to be on macronutrient restrictive diets. Metabolically dysfunctional people may need to follow restrictive diets, but their long-term goal should be to return the body to healthy metabolic function, and the primary way to do that is regular physical activity.

Inactivity and Metabolic Health IV

See the rest of the posts in this series here.

I’d hoped to be able to add a post to this series once or twice a week, and am finding it tricky to find the time. Darn day job. Anyway, if you want to see the collection of studies I’m pulling from for this series, it’s all pinned on my Inactivity and Metabolic Health pinterest board. I add new stuff there all the time.

The study I’m looking at today was part of the Heritage Family Study, which is a pretty massive undertaking looking at the role of genetics in a person’s cardiovascular and metabolic response to exercise. The Heritage Family Study is funded by grants from the NHLBI, which is one branch of the NIH. IE, the government. So naturally, some will dismiss this study as biased (anything government funded is highly suspect to a certain dogmatic faction of the alternative health and diet industry), although I’m not sure what investment the government has in getting people to exercise, other than improving public health and reducing health care costs. In any case, that’s a brief overview of the ‘parent’ study, take it as you will.

The Effects of Exercise Training on Glucose Homeostasis

This specific study was designed to

“…examine the effects of a 20-week endurance training program on insulin sensitivity, insulin secretion, and other IVGTT-derived [IVGTT=intravenous glucose tolerance test] variables while considering the potentially confounding effects of sex, race, age, and BMI.”

In other words, they wanted to see how people of different ages, genders, races and weight status responded to 20 weeks of exercise training. All participants were sedentary at study outset. 316 women and 280 men participated, so it’s a good sized study. The exercise protocol consisted of 3 session a week of cycling, starting at a duration of 30 minutes and increasing in intensity and duration to 50 minutes 3 times a week at study end. Each participant had an IVGTT before commencing exercise, and again very near the end of the 20 weeks (there was some variation in exact time of the second IVGTT due to availability and menstrual status of female participants, they wanted to ensure all the women were at the same stage of their cycle when the test was performed). Fasting plasma glucose and insulin were also tested 1 and 3 days after the last exercise session.One drawback of the study is that there was no control group, a limitation of the structure of the Heritage Family Study.

As you can probably expect, there were improvements across the board in metabolic parameters. Improved insulin sensitivity, glucose tolerance, insulin response, etc. There were also patterns in the differences in response between groups. Men and people with initially poorer metabolic responses saw greater improvements than women and those who were initially more metabolically healthy. There were some interesting findings in regard to a protective effect of exercise in regards to both hyperglycemia and the hunger and food seeking behaviors associated with hypoglycemia, as well as this tidbit:

“…the quartile with the [initially] lowest glucose tolerance registered an increase in insulin secretion following regular exercise. This increase in insulin secretion as well as the overall 11% increase in glucose effectiveness, which reflects the capacity of glucose to mediate its own disposal, may have contributed to the improvement in glucose tolerance.”

Ie, an increase in insulin secretion accompanied an increase in glucose effectiveness and tolerance. Insulin is not the bad guy. Insulin RESISTANCE is. And insulin resistance is caused by energy imbalance, inactivity and genetics. This study gives some insight into that genetic component.

There’s a lot of information here, and the full text of the study is available for free, so take a look, I try to keep these posts short and user friendly, so I won’t go into further detail here, and I’ll invite you to read the science for yourself.

Lifestyle Deficiencies and Metabolic Health: “It’s the Metabolism, Stupid”

Or, the Go Kaleo Theory of Everything™.

Obnoxiously overdramatic visual.

My lightbulb moment: the day I understood that my body and my health were a reflection of my habits, and that in order to have a healthy body I needed to engage consistently, over time, in the behaviors that promoted health. The body needs certain conditions to be met in order to function optimally, most people ‘get’ this on a nutritional level. We understand nutritional deficiencies:

  • A Vitamin D deficiency leads to Rickets.
  • A Vitamin C deficiency leads to Scurvy.
  • A protein deficiency leads to Kwashiorkor.
  • A calorie deficiency leads to Marasmus.
  • A B12 deficiency leads to pernicious anemia.

Etcetera. We understand that these conditions are the result of fundamental needs not being met, and that the ‘cure’ is to meet that need. It’s not really a ‘cure’ though, it’s returning the body to homeostasis, the body’s natural state when the conditions for health are in place. We don’t further alter the diet or lifestyle to mitigate the symptoms of the deficiency. That would be silly. Lets consider what that might look like (cue dream-sequence harp music):

Imagine for a moment that you are dealing with the symptoms of a vitamin D deficiency. You’re experiencing bone and muscle pain, you’ve had a few bone fractures, and you’re developing multiple cavities. You find a blogger online who also has those symptoms, and that blogger has developed a novel new approach to addressing them: daily painkillers for the pain, using a scooter to get around to reduce the risk of falls (and subsequent fractures), and teeth removal to eliminate the cavity issue. Indeed, this approach seems to mitigate all of your symptoms! A miracle indeed! And no need to resort to pesky vitamin D supplements. Why supplement when you can simply take painkillers, pull out all your teeth, and use a scooter to get around? Deficiency be damned. You do some further investigation and discover that there’s a huge online community of people who’ve adopted this lifestyle to deal with their symptoms. Blogs, facebook pages, books, heck, there are even doctors who advocate this lifestyle! You fit right in. You join a few facebook groups, make some online friends, and settle in to your new lifestyle. There are even conferences and social gatherings where you can meet fellow ‘low-Ders’, exchange tips and stories, and generally receive affirmation and reinforcement for your lifestyle choices.

Of course this sounds absolutely absurd. But we do it all the time. Let me explain…

I had my lightbulb moment long before I’d heard of ‘evolutionary health’. At first, my understanding was nebulous and visceral. I sensed that I needed to create the conditions that my human body was adapted to in order to improve my health. You know, the way zoos try to recreate animals’ natural habitat in order to keep them healthy? You put a lion in a penguin habitat and pretty soon you’ve got a sick, or dead, lion. Well, I sensed that my ‘habitat’ and lifestyle wasn’t appropriate for my health. I was sick after all.

I began with simple logic. What conditions are humans adapted to? Remember, I hadn’t heard of evolutionary health yet. I was just thinking critically. What conditions were ubiquitous for our species as we evolved? I could only think of a few, as we’ve managed to thrive in so many different environments, and those few constants, as I saw them were:

High levels of physical activity.

I’ve since heard the speculation that primitive man’s life was largely sedentary, but this argument makes zero sense to me. Without technology to do the tasks of daily life, living is hard work, no matter how you slice it. Even the simple act of pooping requires physical exertion. Don’t believe me? Stop using a toilet to poop for a few months and see what happens to your thighs. Mmm-hmm. That’s right.

No, up until the last 50 years or so, when we started sitting down most of the time, life was hard work. Everywhere you went you walked, or later, rode a horse, but even that requires physical exertion. You carried things, you climbed things, you dug things up, you skinned animals, you chased prey (or ran from predators), you built shelters, you migrated to follow the seasons or the herds. And there was no TV or internet, so when you weren’t working your ass off in the pursuit of food and shelter, you DID stuff to keep yourself occupied. You danced, you played games, you made stuff with your bare hands, you explored. You never sat motionless for hours on end. That is a 20th century invention. Studies on modern-day hunter-gatherer societies show that even though their total energy expenditure is about the same as westerners, hunter-gatherers are significantly more physically active.

Our genome is evolutionarily adapted to high levels of physical activity. It just is. I hate to break it to you. Physical activity is a fundamental requirement for normal metabolic function, without adequate physical activity we develop insulin resistance and then a whole cascade of metabolic and endocrine dysfunction. I’m not pulling this out of my ass, or cherry picking data, by the way. The Mayo Clinic, Johns Hopkins, the NIH and the NDIC and other reputable scientific organizations agree that inactivity is a primary driver of metabolic dysfunction. Attempting to treat the symptoms of insulin resistance with extreme dietary restrictions, which is what SO MANY in the fad diet, ‘real food’ and ‘ancestral health’ community (which at this point has completely jumped the shark) are trying to do, is like treating the symptoms of vitamin D deficiency with pain killers and teeth pulling. Pain killers and teeth pulling may help in the short term, but establishing healthy vitamin D levels is what is necessary to return the body to ‘normal’ function. The answer is not to tailor the diet to one’s activity level, the answer is to maintain the activity level that supports healthy metabolic function. Otherwise you are merely treating the symptoms of the deficiency. The physical activity deficiency.

Sunlight and sleep.

Variations in skin color are an indication that our genome is adapted to sun exposure. The more sun a geographic location gets, the darker the skin of the people who traditionally inhabited that area. We require sunlight to synthesize vitamin D (there’s my analogy, lol), an essential nutrient for health, which indicates, to me at least, that sunlight has been a ubiquitous condition during our evolution. Same with sleep, we can’t be healthy without it. Attempting to circumvent the health ramifications of sunlight or sleep deficiency by simply addressing the symptoms would be foolish. If you have a sunlight or sleep deficiency, the solution is simple and obvious, get some sleep or sunlight. Fortunately we can get vitamin D from food, an adaptation to living in geographic areas with less sun exposure I’m sure, but just try to hack sleep deficiency. Not happening. We require these things to be healthy, because we’ve evolved under these conditions.

Whole or minimally processed foods.

For the vast majority of human history we’ve eaten foods in the form nature provides to them, or very close. Until the last century, processing of food was minimal: cooking, grinding, fermenting, drying, etc. Only recently have we begun extracting, isolating fractionating, hydrolyzing, etc. Given enough time we could surely adapt to these processes  (we are a highly adaptable species after all, a trait that accounts for our success), and in fact I think we can get away with eating some processed foods because we’re so adaptable (I do), but our bodies are adapted to absorbing and metabolizing nutrients in synergy with the other nutrients that occur together in whole foods, so eating mostly whole foods is probably best in the big picture.

That said, I’ve heard arguments that we’re evolutionarily adapted to specific macronutrient ratios, and I find this line of thinking completely ridiculous. Because we’ve found ways to thrive in almost every environment on earth, we’ve been able to adapt to the foods provided by those environments. The Inuits thrive on a diet of mostly fat, while the Kitavans thrive on a diet of mostly carbs. And somewhere on earth, you’ll find a culture that thrives on every macronutrient ration in between. We eat animals, we eat plants, we eat grains and legumes, we eat insects, we eat fungi, we eat crustaceans, we eat mollusks, we eat honey, we eat algae. And more. We like sweet things and we like fatty things. We’ve found ways to thrive on virtually anything the earth can provide. The common thread isn’t a macronutrient ratio, the common thread is whole, or minimally processed, foods.

Energy balance.

Here’s where I get really philosophical. I believe that any given environment provides a finite amount of caloric energy to support the life that exists there. The variation in human size from individual to individual (and from culture to culture) suggests to me that different ‘strains’ of humans evolved symbiotically with their environment. Environments that provided more caloric energy produced larger humans, and vice-verse. A person’s energy needs are directly proportional to their size (and to a lesser extent their activity level, but BMR makes up the lion’s share of our daily energy expenditure, and BMR is in direct proportion to body weight). When we consistently, over time, consume more or less energy than our body requires, we develop metabolic dysfunction. Too much energy leads to excess adipose storage, and excess adipose produces inflammatory compounds, excess estrogen, and drives insulin resistance. Insufficient energy intake leads to thyroid and reproductive hormone imbalance, fatigue, depression and insomnia, bone and organ deterioration, and a whole host of other issues. We’ve strayed from our natural relationship with our environment and the energy it provides. We have unlimited calories available to us for the first time in human history, and some of us go to the opposite extreme and decide to restrict our intake below what is necessary to sustain health. When we had a more symbiotic relationship with our environment, our bodies adapted to the energy resources it provided. We’re all out of whack now. And energy balance DOES matter. Anyone who claims otherwise is selling a magic pill.

There you have it. My Go Kaleo Theory of Everything™. Re-create the conditions we’re adapted to if you want to support metabolic health (because metabolism is, after all, everything). When I started out on this path five years ago it was an instinctive sense that I needed to change my behaviors and lifestyle conditions to improve my health. Over the years I’ve done research that has consistently reinforced my original instinct, so that at this point I’ve fleshed out my ideas with facts and scientific data. Putting my ideas into practice in my own life WORKED, not only did I lose weight, but I reversed PCOS and several other nagging conditions. I’m five years in and have maintained my weight loss and health by maintaining health-promoting lifestyle behaviors. I am not perfect in any area, but I am consistent in all of them. Day by day, habit by habit, I focused on changing my behaviors, not on changing my body. And new behaviors produced better health.

me·tab·o·lism

/məˈtabəˌlizəm/

Noun

The chemical processes that occur within a living organism in order to maintain life.

Inactivity and Metabolic Health III

See the rest of the posts in this series here.

Today we’re looking at a cross-sectional study on 456 adolescents between the age of 10 and 18, conducted in Brazil. The purpose of this study was to measure and analyze the association between metabolic syndrome and physical activity in this population. You can see the study here:

Physical activity, cardiorespiratory fitness, and metabolic syndrome in adolescents: A cross-sectional study

Anyone with diabetes or on medication that altered blood pressure, glucose, or lipid metabolism was excluded. Each subject was evaluated for height, weight, waist circumference, and blood pressure, and blood tests were conducted to determine HDL, blood glucose and triglycerides. Results were used to evaluate the prevalence of metabolic syndrome, using standard Metabolic Syndrome criteria (abdominal obesity, high blood pressure, low HDL, high blood glucose and high triglycerides).

Each subject also completed a Three-Day Physical Activity Record, and their cardiorespiratory fitness was estimated using the 20-meter shuttle run test. Then this information was used to determine the prevalence of MetS and its components with respect to different cardiorespiratory fitness and physical activity categories.

The results? Higher cardiorespiratory fitness was inversely correlated with Metabolic Syndrome. Physical activity itself wasn’t correlated, which means that is exercise specifically, and the cardiorespiratory fitness it produces, that provides the protective effect.

In this study low cardiorespiratory fitness was shown to already be affecting metabolic health even in adolescence. I will be posting more studies in the upcoming weeks exploring this connection across the lifespan (no, it’s not just kids that are protected by exercise. The protective effect continues throughout life).

Inactivity and Metabolic Health II

You can view all of the posts in this series here.

Today’s post is PCOS specific, a subject I take special interest in as I lived with symptoms of PCOS for nearly 25 years before putting the pieces together and taking the steps necessary to overcome my symptoms. (You can read about my experience with PCOS here.)

PCOS is a metabolic disorder with a strong insulin resistance component. Many women with PCOS eventually develop diabetes as well. Addressing the insulin resistance is key.

Metabolic and cardiopulmonary effects of detraining after a structured exercise training programme in young PCOS women.

In this study, 64 young, overweight women with established PCOS were divided into 2 groups: one recieved 24 weeks of exercise training, the other recieved 12 weeks of exercise training followed by 12 weeks of de-training (they stopped exercising). Metabolic parameters were assessed at baseline, at 12 weeks, and again at 24 weeks.

At the 12 weeks assessment, both groups showed significant improvements in insulin sensitivity and glucose levels, lipid profile, and cardiovascular health. At the 24 weeks assessment, the first group (24 weeks of training) showed even greater improvements, and the second group (12 weeks training, 12 weeks detraining) showed no improvement over the baseline assessment. They lost all the gains they had made during the first 12 weeks of training.

The moral of the story here is that regular exercise is key. In my personal experience, type and intensity of exercise is far less important than consistency. It matters less what you do, just do something, and keep doing it.

Inactivity and Metabolic Health I

I’ve decided to do a series of blog posts highlighting some of the studies I’ve collected exploring the link between physical activity and metabolic health (specifically Insulin Resistance, as it’s central to many metabolic diseases including PCOS and Diabetes, and probably at least partially causative in more far ranging diseases such as cancer and Alzheimers, among others). You can view the entire series of posts here, keep in mind that I started this series on January 10, 2013. There will eventually be dozens of entries.

Today I’m looking at this study from the New England Journal of Medicine:

Increased Glucose Transport–Phosphorylation and Muscle Glycogen Synthesis after Exercise Training in Insulin-Resistant Subjects

The study drew from an initial pool of 55 subjects. All were between 19 and 45 years of age, and all were the children of people with Non-Insulin Dependent Diabetes Mellitis (NIDDM), meaning they all had a genetic risk factor for developing Diabetes. All were in good health and within 8% of an ideal body weight. Anyone who smoked, was on medication, was very sedentary or very active, or who had high blood pressure was excluded. From this pool, the study authors drew the 10 subjects with the highest degree of insulin resistance at study onset. A group of 8 subjects matched for age, weight and activity level, but who didn’t have a parent or parents with NIDDM, were selected for control. All subjects were placed on an isocaloric weight maintenance diet (which means they were put on a diet that provided the proper caloric intake to maintain the weight they were at when the study began).

The purpose of this study was to determine the effects of exercise training on the subjects’ insulin sensitivity. Several markers of insulin sensitivity were measured at study onset, after an initial exercise session, and again after 6 weeks of exercise training. The exercise protocol consisted of 3 15 minute intervals of stair climbing, four times a week.

The exercise-training program improved insulin sensitivity by 43%, and whole-body nonoxidative glucose metabolism by 60 to 70 percent in both groups. For perspective, Metformin, one of the most frequently prescribed medications for insulin resistance, generally improves insulin sensitivity by 16-25%.

The study goes into some detail regarding the mechanisms by which exercise improves insulin sensitivity, so if you’re interested in learning more, click on through.

Improving insulin sensitivity is the first line of defense against the development of Diabetes, and exercise improves insulin sensitivity better than the most effective medications. Insulin resistance has been linked to a whole host of diseases, so any protocol aimed at reducing metabolic risk that doesn’t include regular exercise is highly suspect in my eyes. Yes, there are fad diets out there that discourage exercise and/or claim that it’s unnecessary (as long as you eat the ‘right’ foods). In this series of blog posts I intend to shed some light on the fallacy, and ultimately the danger, of such philosophies. Keep watching the blog, I’ve got dozens and dozens of these studies to share and will be posting with some regularity.

Take Two Aspirin, and Die of a Brain Tumor Anyway

Inactivity and energy imbalance are scientifically established fundamental CAUSES of metabolic dysfunction (see: Johns Hopkins, Mayo Clinic, NIH and NDIC). Any diet program that doesn’t address inactivity and energy imbalance is merely addressing the SYMPTOMS of metabolic dysfunction.

That doesn’t mean one shouldn’t address the symptoms. If I had a brain tumor that was causing headaches, you can bet I’d be taking painkillers for the pain. But I wouldn’t stop there, I’d treat the tumor as well.

Treating the symptoms of metabolic dysfunction is all well and good, but for true health to manifest, the CAUSES must also be addressed. It seems to me that a lot of dietary dogma is little more than a desperate attempt to circumvent the negative consequences of poor lifestyle choices: too much or too little food, inadequate physical activity, or in some more rare circumstances, overtraining (although I think most cases of overtraining could be resolved by simply eating enough calories to fuel the increased activity), inadequate sleep.

This is not to say dietary optimization is useless. Quite the contrary, maximizing the nutrient density of one’s diet can be very helpful, as can optimizing the macronutrient ratio to meet one’s unique goals and needs, just as painkillers can be helpful to the victim of a brain tumor. But far too often, dietary optimization is taken to an extreme, by dieter and guru, while simultaneously ignoring energy balance and physical activity, or worse, claiming that energy balance and physical activity don’t matter as long as a person is eating the ‘right’ foods. This is irresponsible in the extreme. It’s akin to prescribing painkillers alone as a treatment for a brain tumor. Helpful in the short term, but ineffective in establishing long-term health

My primary criticism of dietary dogma (aside from the divisiveness it breeds) is it’s general tendency to shift focus onto the symptoms of metabolic dysfunction, rather than the cause. Both are important. Without addressing and changing the behaviors and lifestyle factors that foster metabolic dysfunction, there will be no true healing.