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Is There An App For That?

>> Saturday, November 28, 2015

One day in clinic, I was following up with one of my hyperthyroid patients, and discussing how her heart rate had been running on her current treatment.  I had taught her how to check her radial (wrist) pulse at our last clinic visit.  When I asked her about checking her pulse, she said 'I just use an app for that!'.  An app?! I said.  She pulled out her iPhone, opened her free Heart Rate app (google 'Instant Heart Rate - Heart Rate Monitor by Azumio for Free), placed her finger over the camera light, and BAM! her live heart rate appeared.  Very cool.

While I can't comment on the reliability/accuracy of this or other apps (there are no health regulatory agencies that I am aware of that control or test these programs), there are certainly oodles of apps out there that are geared towards health monitoring, from calorie counts to exercise to nutrition to many others.  With the advent of the Apple Watch and other related technologies, the choices and variations are going to continue to rise exponentially, and will further integrate physiologic measures such as heart rate, and possibly even blood sugar.

So today's post is a shout out to you - are there any cool/useful health apps that you like to use?  Please post your responses as comments directly under this blog post.

Follow me on twitter! @drsuepedersen © 2015


Could A Virus Cause Obesity?

>> Friday, November 20, 2015

Among the numerous complex contributors to obesity, it has long been wondered whether infections, such as viruses, could be a contributor to the obesity epidemic.

In fact, it turns out that a common cold virus, adenovirus-36 (AD-36), has a link with obesity.

Antibodies to AD-36 (showing evidence of previous exposure) have been found in 30% of adults with obesity, compared to only 11% in normal weight adults.  In kids, the story is similar, with 22% of kids with obesity carrying AD-36 antibodies, versus only 7% of kids with normal body weight.

Also interestingly, in parallel with the rise in obesity, AD-36 antibody positivity has increased from 7% in 1992-1998 to 15-20% in 2002-2009.

There are a number of mechanisms by which AD-36 may induce obesity, including:
  • Induction of fat cell formation (in scientific terms: adipogenesis from stem cells via PPAR-gamma signalling pathways)
  • Inflammation induced by the virus (release of inflammatory chemicals has a number of effects on human physiology which contribute to obesity)

Interestingly, while people exposed to AD-36 have a higher rate of obesity, they seem to also be protected from metabolic complications associated with obesity, such as type 2 diabetes and fatty liver.  Mechanisms include: 
  • increased uptake of sugar into cells (increased GLUT4-mediated glucose uptake)
  • an increase in adiponectin, which is an anti-inflammatory hormone made by fat

So, the ultimate success would be if we could vaccinate against AD-36, but also harness its power to decrease the risk of metabolic syndrome.  We are not close to either goal currently, but empowered with this knowledge, research is underway with both of these goals in mind.

Follow me on twitter! @drsuepedersen © 2015 


Exercise Prescriptions - How They May Differ in Obesity

>> Friday, November 13, 2015

In follow up from my recent blog on the Home VO2max text, let's now talk about resting VO2, which is the amount of oxygen we consume at rest per kilogram of body weight per minute, and therefore a measure of basal (resting) metabolism.  This blog post is a little heavy in the math details, but trust me, well worth it to understand for anyone who struggles with their weight, and for any health care professional who cares for people with obesity. Read on!

There are many things that affect resting VO2, including:

  • Age (resting VO2 decreases with age)
  • lean body mass (resting VO2 is higher with more muscle) 
  • higher Body Mass Index (BMI) - resting VO2 decreases with higher BMI.  In other words, people with obesity may have a lower resting VO2, and this gets lower with more excess body weight.  This is due to a number of factors, including genetics, sympathetic nervous system tone, and also because fat tissue is less metabolically active per kg.

The amount of oxygen we consume at rest is equal to one MET (metabolic equivalent) of energy. The amount of oxygen used and energy burned (Calories or kcal) at rest is generally assumed as follows:

Resting VO2 = 1 MET = 3.5 mL/kg/min of oxygen

1 MET = 1 kcal/kg/hour of energy burn

We often describe physical activity in METs:
  • Light activity: less than 3 METs
  • Moderate activity: 3-6 METs
  • Vigorous activity: 6 METs or more

For example: 
  • walking at 4 miles per hour is about 3-5 METs (moderate activity)
  • shovelling dirt or light snow is 5-7 METs
  • jogging at 5mph is about 7-9 METs
  • shovelling heavy snow or playing squash is 9 METs or more

A full compendium of METs with particular physical activities can be found here.

Key Point: For some people with obesity, because they may have a lower resting VO2 and therefore a lower resting MET, 'moderate activity' of walking at 4 mph may actually be well into the vigorous METs category for them.

To assign a person with obesity who has a much lower resting VO2 a 'standard' moderate exercise prescription may result in this person feeling heavy exertion at that level of intensity - a potentially unsafe leap in exertional intensity, and also leaving one feeling discouraged that the activity feels too intense to continue.

Therefore, attention health care professionals:  When helping a patient with creation of an exercise prescription, it is important to listen to your patient (as always!), and understand what kind of activity gives them what level of perceived exertion - you may need to start the exercise prescription for your patient with weight struggles at a lower level of activity.   Most exercise prescriptions start with a moderate level of exertion, so for example, if walking at 2mph gives your patient a sense of moderate exertion, this would be where the exercise prescription would start, and you and your patient can build upwards from there.

If you are personally thinking about embarking on an exercise program, be sure to speak with your health care professional to see if any health checks need to be done before you begin.  When you and your health care professional are ready for you to begin, use this awesome METs compendium to find something fun - the choices are endless!

Follow me on twitter! @drsuepedersen © 2015 


How Fit Am I? The Home VO2 Max Test

>> Friday, November 6, 2015

Ever wonder how fit you are, or if this could be measured?  The best measure of aerobic fitness is called the 'VO2max', and is literally equal to the volume of oxygen consumed per minute during maximum exercise effort.

How does VO2max reflect fitness?  Well, we use oxygen to generate energy (called ATP) at rest and during aerobic activity.  Energy can be generated without oxygen for very short periods of time, which is called anaerobic respiration, but the best marker of endurance/cardiorespiratory fitness (which requires oxygen) is the maximum possible oxygen consumption that a particular person can achieve - that is, the VO2max.

The VO2max is most accurately measured in a lab, where oxygen consumption is measured while a person exercises to maximum capacity on a treadmill or stationary bike.

There are a couple of neat ways that VO2max can be predicted: (IMPORTANT: check with your doctor to make sure it's safe for you to do these tests before you proceed)
VO2max ranges and what they mean for fitness level can be found here.

To learn about VO2 at rest, how this translates into METs, how this is important for exercise prescriptions, and how this can be different in people with obesity... stay tuned to for more!

Follow me on twitter! @drsuepedersen © 2015 



I am excited that you have arrived at my site, and I hope you are too - consider this the first step towards a Healthier New You!! As a medical doctor, Endocrinologist, and obesity specialist, I am absolutely passionate about helping people with weight management. Though there is certainly no magic cure for obesity, there IS a successful treatment plan out there for you - it is all about understanding the elements that contribute to your personal weight struggle, and then finding the treatment plan that suits your needs and your lifestyle. The way to finding your personal solution is to learn as much as you can about obesity: how our toxic environment has shaped us into an overweight society; the diversity of contributors to obesity; and what the treatment options out there are really all about. Knowledge Is Power!!

Are you ready to change your life? Let's begin our journey together, towards a healthier, happier you!!

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