Sunday, September 17, 2017

Stuff I Learned - Getting out of Bed

In the first week of my Exercise Physiology course we studied how the circulatory system responds to changes in position, particularly in the transition from supine to standing. If you're anything like me, you may consider studying getting out of bed about as interesting as sodden cardboard. Interestingly, it turns out that this seemingly simple transition involves numerous adaptations that are unique to the human organism.

One of the problems with our human-ness involves rearing up on our hind legs. OK - so being a biped isn't necessarily a problem, though the vertical orientation creates some serious design challenges. Our brains are at the top of our vertical bodies, which means that gravity is constantly pulling blood away from our brains. Brains are very hungry consumers of blood (much like zombies are hungry consumers of brains) and if the brain doesn't get a sufficient blood supply, you will quickly pass out.
Buddy Cat has 70% of his blood above his heart. Like any quadruped, this means that getting blood to the brain isn't all that difficult - the blood is already above the heart and is pretty close to the brain. Humans, on the other hand, have 70% of their blood below their hearts. This means that our hearts have to work hard to pump the blood uphill into the brain. 

When you move from supine to standing, you're at risk of game-over. What keeps us (mostly) from passing out when standing up? It's actually a series of adaptations that facilitates this seemingly simple transition.
  • Your rest and digest (parasympathetic) nervous system lowers your heart rate while you're resting. Upon standing, the parasympathetic nervous system stops lowering your heart rate, and your heart rate increases quite a bit in what's called parasympathetic withdrawal. For a few moments, your faster heart beat will help pump blood uphill to your brain.
  • Unfortunately, the heart can only pump what it receives, and when you first stand up most of the blood remains stuck in the floppy veins of the legs. Thankfully, your body has the capacity to "tighten" the veins (vasoconstriction) to help facilitate the flow of blood upward into the brain. Upon standing, vasoconstriction helps move the blood out of your legs and up into your torso.
  • In moving from supine to standing, you use muscles in your legs to accomplish that transition. The contracting muscles squeeze the veins, which further helps to push the blood upstream and into your brain.
  • The muscle pump is accompanied by the respiratory pump. (I wrote about the respiratory pump in an earlier blog posting.) When you inhale, the pressure in your thoracic cavity is reduced, which tends to pull blood uphill and into your heart. When you exhale, the pressure in your thoracic cavity increases, which tends to push the blood out of your heart. The respiratory pump also helps to improve circulation to the brain.
  • In your abdominal cavity, organs also help in this process of moving blood. For example, your liver is capable of storing a significant amount of blood volume. Related to the respiratory pump, when you breathe, blood that's stored in the liver is lifted upward into active circulation.
These are just a few of the adaptations that are unique to the human animal. I'm just getting back into the rhythm of the new school year, so I'll keep this first blog posting brief and to-the-point. I look forward to learning more and sharing more about this wondrous vehicle that we each inhabit.

'Til next week!

Thursday, August 17, 2017

Skinny, Whole and Lo-Pro

To extract the most from my body, I’ve turned to three dietary strategies that I believe support my fullest health and vitality. I maintain a busy schedule with grad-school, teaching and family/social commitments, and I have come to believe that Skinny, Whole and Lo-Pro help me to get more done.

Food and weight are inevitably topics that are strongly infused with emotion. In sharing my ideas and experiences, I hope that you take a few moments to reflect on the vital fuel that you ingest. Are the foods that you eat supporting your fullest expression of life? Or not? While these approaches have worked well for me, they may or may not work for others.

The organic garden at Crestone Mountain Zen Center.
Skinny, as the word implies, refers to my weight. I’ve long tracked the work of the various scientists that study Calorie Restricted (CR) diets. While some adherents take the idea to what I consider extremes, I believe that the emerging scientific evidence supports the health benefits of being skinny. What do I mean by skinny?

There are many ways that we can define skinny – rather than waving my hands in trying to describe skinny, I prefer to reference Body Mass Index (BMI) in this discussion. BMI describes the relationship of your height to your weight. It's not a perfect gauge of skinny/normal/overweight, though it can give you a pretty good sense of your relative proportions. A BMI of 18.5 to 25 is considered normal weight, while BMI below 18.5 is considered too-skinny, and a BMI over 25 is considered overweight. While some of the CR adherents believe in maintaining a  BMI well below 18, I am of the opinion that there is such a thing as being too skinny. As a result, I’ve rather arbitrarily picked a BMI of 21 as my target weight. I think that being on the lower end of normal hedges my bets; I’m pretty skinny if it turns out that CR is really beneficial for health, and not so far out in the ozone if it turns out that CR works better for canines, rodents, and non-human primates than it does for humans!

At the very least, I feel much more energetic when I’m skinnier. As I mentioned in a previous blog posting, most of my body’s aches and pains have disappeared since losing the 40+ pounds that I’d put on since college. In no small measure, I think my capacity to keep up with colleagues that are half my age is related to carrying less weight around.

In addition to maintaining a lower BMI, I also focus on eating whole, unprocessed foods. Over twenty years ago I swore off packaged foods than contained artificial colors, flavors and preservatives, and almost immediately I felt much better. Recently I’ve gone a step further and now focus on eating foods that are closest to their natural state. I am a big believer in cooking food; other than cooking, I strive to alter food as little as possible in its transition from the soil to my belly. Here are some examples:

-I sprinkle freshly ground flax seeds on my salads in lieu of consuming flax oil (much cheaper, too!)
-I make smoothies at home out of whole fruit rather than purchasing pasteurized smoothies at the store (again, much cheaper!)
-A bowl of lightly steamed vegetables really doesn’t need dressing – a squeeze of lemon and a dash of salt helps bring out the food’s natural flavors

As an added bonus, when I eat the simplest and most whole foods, I need less food to maintain my chosen weight. I used to eat 2600+ calories/day to maintain my weight, and since shifting to even simpler foods, I am now maintaining my weight on significantly less than 2000 calories/day. Consuming less food equals lower grocery bills, which allows me the luxury of choosing higher quality foods to eat!

Lastly, I intentionally restrict the quantity of protein that I eat. Yes, you read that correctly – I am not a believer in high protein consumption. When people ask about my vegan diet, almost inevitably they’ll ask where do you get your protein? When I reply that I’m not really too concerned about beefing (sorry – bad reference) up my protein consumption, I get some pretty incredulous looks!

No doubt, protein is an essential nutrient that helps build tissues. I love to run and be physically active, so I’m interested in consuming enough quality protein. That being said, the scientific evidence consistently suggests that the average person should consume 0.8 grams of protein per kilogram of body mass. I weigh 83 kilograms, which translates into needing 66 grams of protein per day. Most food contains protein (yes, even many vegetables contain a surprising quantity of protein.) When I periodically track my food consumption, I inevitably find that without even trying, I’m easily consuming sufficient quantities of protein (generally 80+ grams of protein/day) Contrary to common belief, protein is not involved with providing energy in the way that fat and carbohydrate are. In addition, your kidneys have to work hard to process protein – why strain your kidneys by eating more protein than is needed?

My approach to food is a work in progress, though I’ve been really enjoying the past year of Skinny, Whole and Lo-Pro eating. As I embark on another busy academic year, I’ve come to believe that my approach to food is a significant contributor to my capacity to juggle home, work and school responsibilities at an age when the AARP is bugging me to join their ranks!