Category: Biology

Categories
Biology Diabetes Health

Diet or Diabetes

To be or not to be

Sweetness has always been associated with good things. And sugar has been an obsession for many. But sugar has a good many effects that are not good. And some are affected in worse ways than others. We need a certain amount of glucose in our systems to live. That amount has been described as about a teaspoon in all of our blood at any given time. The rest has to be consumed, excreted or stored. Most of us who love sweet things rarely consider what the impact of consuming large quantities could be.

Epidemic

There is a national epidemic of overweight & obesity, metabolic syndrome and diabetes that was become worse over the past 30 years. While there have been many articles written and documentaries made the situation has become worse and worse. Nutritionally dense processed food tastes good and recently we have begun to realize that salt, sugar, and carbohydrates are behaviorally addictive. My belt size and weight had gone up over the past several years and my workouts did not seem to be having any impact. After several months of my youngest daughter insisting I have a physical (and stop putting so much sugar in my coffee) and signing a contract with her I listened. 

Lose It 

On July 17 I had a physical examination and was told to lose 30-35 pounds and essentially get to a weight that I had not been at since I was running 50 miles a week. I was told to give up  pasta and bread and to skip potatoes. Thinking about all the delicious fresh, home-made bread my wife makes, along with lasagna, pesto, all sorts of pasta, and my love of pizza I said “No way. My wife is Italian. I don’t think that is going to happen.” I considered the near impossibility of losing just 5 pounds. Maybe with a tremendous effort it would be possible to drop 15. 

Motivation: Blood Sugar Sky High

But one day later, I was told I had a random blood sugar of 180 and an A1c of 8.5 (which indicated an average blood sugar of around 220) .  My doctor suggested a low carb diet, but was doubtful I’d follow through after my response the day before. He also suggested perhaps I visit an endocrinologist and take Metformin. I said “no thank you” to the idea of Metformin and said I thought we could handle this ourselves. 

I had an immediate change of heart and felt this was a great time to be motivated for a dramatic change in diet. What did I think I needed most?

  • Need to not be diabetic.
  • Need not to be on unnecessary medication.
  • Need to work on problems caused by being overweight:
    • High A1c and Blood Sugar
    • Overweight
    • Clothes fit
    • High Blood Pressure
    • Need to face up to the impact of diet health.
  • Need to realize that one can not live by workouts and the gym alone. 
  • Need more energy. Lately energy had been slacking from my unknown high blood sugar

Thinking about the domestic and global epidemic of overweight and obesity, I had to face the fact that I was joining this group and needed to change.

Changes: Trim the carbs. Keep the fat

I knew there were two possible ways to handle a dietary change. One was a vegan or vegetarian diet and the other was a low carb diet which is nutritionally ketogenic also called “Keto”. I was well aware that Tim Noakes had embraced this diet and received opprobrium in return. You can google his story which he describes quite well in both book and on YouTube. But as a long time follower of his I knew he had advocated a LC/HF (low carb – high fat) diet for years. He called it the “Banting Diet” after  William Banting who wrote  “Letter on Corpulence, Addressed to the Public” advocating this low carb diet for weight loss back in the 1800’s. Claude Bernard, a French physiologist, known for the concept of “homeostasis” had previously described a diet for diabetes which eliminated bread, butter, milk, sugar, beer and potatoes.

To me this approach made sense, although I know of people who have lost significant weight with a vegetarian approach. Eliminating most carbohydrates which would lead to higher glucose and a very variable blood glucose seemed logical. A quick literature search easily brought up dozens and dozens of academic articles. Further looking led to podcasts, online lectures, and books on the science, beginning Keto and Keto Cookbooks to read. And to my surprise, this diet had become popular and to some was known as a fad diet. I have not spent time following diet fads and trends so I had no idea.

Warnings:

I had at least two people tell me the “Keto” diet would kill me. Both were vegan and hopefully were not eating pesticide sprayed fruit. 

The word seemed to be that this diet is a hard road to follow and difficult to sustain.

I was given the task of 1200 kcal per day and decreased carbs. The lowest recommended calories is higher than this, so don’t try this on your own. 

One friend passed on a good number of presentations on the plant based diet, most of which were quite good. But I was well convinced that my path laid with the “Banting”, low carb approach. I also learned of the very hostile politics that is inherent to much of human interaction, and it was also present here in diverging nutritional opinions which should be based solely on science.

Tossing Out The Bread With the Chocolate Milk and Caramel Macchiatos 

Lots had to go. The first thing that came to mind was a lifetime of daily chocolate milk and for as long as I can remember sugar, milk and a touch of cocoa in my coffee.And a good number of cups of coffee each day. In fact, my coffee consumption was enough to power enough calories for  another meal each day. While much of my diet was considered healthy and included chicken, salmon, other healthy fish and vegetables, I did consume sugar chocolate milk, and would have an occasional “chip” binge. Warm, fresh, home made bread with butter was a periodic delight. But now, I can have the butter but not the bread. And over the past few years, ice cream became a joy.

So out went sugar, pasta, high fructose corn syrup, most fruits (except for certain berries), ice cream, fruit juices, chips, chocolate cake, breaded anything, most glutens, wheat flour, a good number of vegetable oils that were not olive oil. 

In came whole eggs, unprocessed bacon, more salmon, fish, chicken, occasional london broil, turkey burgers, blackberries, raspberries, blueberries, 5% Greek Yogurt, a very small daily piece of dark chocolate (85%), 1/2 piece of gluten-free crisp bread with a tablespoon of humus, almond butter, almonds, macadamia nuts and pecans. Much of my vegetables are green leafy kale, spinach but also broccoli, cauliflower, avocados and zuchini. 

Seriously?

This was done immediately, whole heartedly, and very seriously. Absolutely ZERO cheating. I obsessively read all food labels. I started going food shopping. I helped (at least a bit, like a back-seat driver, but tried to help) with food preparation. And I began weighing just about all of my portions.  

And most important I have kept track of my meals in a smartphone app. There are several apps available. I am using myFitnessPal to track food groups and calories. And I used a website to determine a good set of “macros” for protein, fat, and carbohydrate which was easily incorporated into myFitnessPal. 

I had great help from my wife in choosing low carb but tasty food. Some of the early options included chicken rolled in curry, pesto chicken, salmon, and tilapia with a variety of toppings. The vegetables I ate were all at her suggestion. 

Short Term Results

Before my weight went had gone down 3 pounds, my blood sugar dropped to the normal range. At the start my random blood sugar was 180. A week later my fasting blood sugar was 95. And it has not been higher than this since then. My weight has steadily decreased. I was able to stop taking 2 of 3 blood pressure medicines. And I needed to use smaller belts to keep my pants up. My energy level improved. And there was not much in the way of hunger pangs. The diet has been filling without spiking sugar or adversely impacting insulin. 

Longer Term Results

About three weeks in I went out for sushi with my doctor. He noticed the early but significant weight loss and was impressed with my daily blood sugars. I told him of my new found fear of carbs and how the rice in the sushi now scared me. It turned out that the restaurant would roll the sushi wrapped in cucumber without rice. But the surprise was my doctor was following the same diet and we then both happily ate sashimi. 

In less than 3 months my weight went down about 28 pounds and my waist size decreased about 5 inches. My blood sugars both fasting and after eating have all been at normal levels, well below 100, usually in the 70’s and 80’s. And a home test kit for A1c showed my A1c to be down to 4.8. I will have an in office test before the end of October and I expect the then 90 day test to be no higher than that and likely a bit lower. 

Support

At a nephew’s wedding about 6 months ago, I spoke with one of my wife’s cousins. He was definitely enthusiastic about his diet which helped him lose over 100 pounds over a year or two. He didn’t just say that his low carb diet was good. He said it was great and discussed the physiology of it in more detail than most people would even think about. A few months later we met again just after I began the same nutritionally ketogenic HC/LF diet. This time I had a lot of questions to ask. He told me about the importance of electrolyte supplements, fluid replacement and foods that were helpful and those that were not.  And he encouraged me to get a Ketone meter. I did, and use it every now and then. But the results are what has let me know things are working.

About 6 weeks or so into this process I contacted a friend, Mark Cucuzzella MD (https://www.drmarksdesk.com) who is a Family Physician in West Virginia, and on the faculty of the West Virginia University School of Medicine. Dr. Mark is one of the most community oriented people you could hope to meet. He owns a running shoe store, is involved in the racing community organizing and sponsoring races, and he even has a dozen bikes that are lent out to people in the community at no charge. Mark is an active lecturer nationally and around the world on diet, exercise, shoes and biomechanics and health. He has served for years as an Air Force Reserve Lieutenant Colonel. All this and he has maintained a running schedule that has had him completing 30 consecutive yearly marathons under 3 hours. His best time was 2:24. Dr. Mark’s involvement with his community, patients and students is inspirational. 

I remembered from our first meeting a few years ago that Dr. Mark was an expert in nutrition in addition to being involved in the mechanics of running and training. So after finding a good number of interviews, a book and podcasts, I thought I’d drop him a note about what I had been doing. He was very supportive. We also discussed the possibility of using a CGM (continuous glucose monitor) to see what foods might be causing glucose spikes. Dr. Mark immediately sent me a presentation he had done online for physicians and a dozen or so articles on the importance of maintaining a level glucose and the impact of a low carb diet. We had the chance to spend a lot of time together at the annual American Academy of Podiatric Sports Medicine seminar in Cambridge, Massachusetts. His lectures were the best since many of them involved going outside and moving on those beautiful September days.  I’ve learned much from Mark and continue to do so. 

All through these past few months I’ve read journal articles, blogs, listened to dozens of podcasts and online lectures. I’ve read books on getting started on ‘Keto’, books on how the science works and how to handle athletes attempting a low carb diet (it varies), and  books on low carb cooking. There are many resources available. I’d recommend researching the low carb diet thoroughly if you have reason to believe it would be helpful. Your public library is likely to have a good number of books on the shelves, surrounded by a lot of other diet books. But when I visited my library I wasn’t distracted. I knew what I was looking for.  

The Impact of Nutritional Ketosis Over 11 Weeks

Total Weight Loss: 28 pounds 

A1c from 8.5 down to 4.8

Fasting Blood Sugars: In 70’s and 80’s

Blood Pressure: Significantly lower on less medicine

Waist from about 39-40” to 34”

Energy level: significantly improved

So now, my blood sugar is normal. My clothes fit. My blood pressure is improved. And I don’t need to take any medicine to keep my sugar in the normal range. This worked faster and better than I would have believed. 

In an upcoming post, I’ll list some of the authors, researchers and references I found helpful. 

Categories
Biology Sports Medicine Tendinopathy

Ibuprofen Does Not Destroy Tendon Cells

NSAID treatment and tendinopathic tissue

A new study – online at the J Applied Physiology (August 31, 2017)  – was performed to measure beneficial impact on collagen production in chronic tendinopathy. The study evaluated mRNA (and ribosomal RNA) and more along with determining the impact on gene activity.

The study showed that one week of 1800 mg per day of Ibuprofen seemed to not have a measurable impact. The authors propose that the impact in vivo and in vitro may be dramatically different for one of several reasons. The tendon cells may not be sensitive to ibuprofen or they may not be exposed to a high level of ibuprofen in the body

The study did demonstrate that there was a decrease in pain compared to placebo and suggested that the pain reduction pathway may work in ways not yet well described.

The best news was that although it may not have a dramatic impact on chronic Achilles tendinopathy (which we suspected and perhaps knew all along), it did not destroy tendon cells.

Online: J Appl Physiol (August 31, 2017). doi:10.1152/japplphysiol.00281.2017

Categories
Biology Diabetes Health Microbiome

Diabetes Type 2 (T2D), Metformin and The Microbiome

Microbiome analysis is coming soon to a doctor near you. Microgenomics is going to be part of nearly everyone’s future. This week Nature magazine published an article which indicates that at least part of the action of the anti-diabetic medication Metformin may be occurring via the microbiome. At the leastMicrobiome Metformin there is a dramatic difference between the gut microbiota between those with type 2 diabetes (T2D) treated with Metformin (T2D-Metformin+)and those not treated  (T2D-Metformin-).

The article has an excellent discussion both of the direct effects of Metformin and the indirect effects and potential interactions of various gut bacteria

nature15766-f2

 

 

 

 

Reference:

Forslund, K., et al. (2015). “Disentangling type 2 diabetes and metformin treatment signatures in the human gut microbiota.” Nature advance online publication. Accessed Dec. 2, 2015

Categories
Biology Culture Philosophy

Examine Your Models and Theories Often

I’ve been spending far too much time doing 140 character mini blogs or actually enjoying MOOCs (massive open online courses). My favorite MOOCS may be found at EdX.org and Coursera.org. If you are not currently involved in a formal course of study, there probably is no better way to spend time learning than these. But it is time for at least a short blog.

So, off we go to theory. We see many theories proposed and many adopted with little study. We may see a study of 13 people or 20 people that some purport to change all thinking on a long standing medical problem. This is not the proper way to approach a poorly designed and implemented study or even a well designed but entirely all to preliminary study.

We would not change the treatment of heart disease, any type of cancer, or try to prevent Alzheimer’s disease on evidence as weak as this, but somehow it is deemed worthy of a sea change for running injuries. A shower and a change into clean clothes is likely a better use of your time.

But allowing models and theories to last for far too long can be an equally troubling problem. But this is why models and theories must be thoroughly examined. There is no need to adopt an untested theory. And there is no value in making a theory about how to treat a clinical entity and proposing that is how all such entities should be treated without testing clinical results.

Now on to yesterday, in the hope of having a better tomorrow, today!

 

Quinta_Essentia_(Thurneisse)_illustration_Alchemic_approach_to_four_humors_in_relation_to_the_four_elements_and_zodiacal_signs-small

 

Examine your theories and models often.

The model of “humors” as the cause of diseases persisted for over 2,000 years. The Greeks refined this concept in about 400 BC and it persisted for far too long.

Aristotle’s scientific publications also lasted for far too long as unquestioned dogma. And there is even recent praise in both film and print for the wonders of his study of biology. While Aristotle may have been the first to take a systematic approach to science, it is even more important to know your failings and where your knowledge is lacking. A recent book and a documentary by evolutionary biologist Armand Leroi called “Aristotle’s Lagoon” have interesting points to bring forward about Aristotle and his study of Biology. But I’m in the camp of believing that he may have done more harm than good by not successfully encouraging others to better study and verify or disprove his theories. He certainly was a busy thinking man for his time. But unexamined, he dominated western thinking for far too long.

Old knowledge isn’t necessarily knowledge at all. It is more likely a historical artifact or relic. Most medical studies from 100 years ago would not past muster today. So using them to justify someone’s completely unscientific theories is absurd. And I, like many, will even have questions about studies performed last week.

And below we have David Attenborough describing (via Louis Armstrong’s words) what a wonderful world is and Otis Redding performing Sam Cook’s song of that name. (And via the wonders of Youtube you can also find Sam Cook, Dr. John, and even Joey Ramone doing one or the other of these songs.)

 

 

 

 

 

Categories
Biology Running

Epidemic of Thin Hypothyroid People?

Professional runners are lean, but not usually mean. And while they may overtrain, which has a host of manifestations, they aren’t usually found to have overt hypothyroidism.

One endocrinologist in particular has apparently been diagnosing and treating many thin, lean, athletes with “subclinical hypothyroidism.” That is a real diagnosis, in which the TSH values are below what is generally considered abnormal. The estimates of the incidence of this condition range from 5%-10%.thyroid

So many things are altered by overtraining and by having a negative caloric balance in the case of withholding calories that one wonders if it is wise to give athletes synthetic thyroid hormane when they have a normal, but borderline TSH level. Could giving thyroxine lead to heart arrhythmia or decrease heat tolerance? Could it enhance performance although it isn’t on any prohibited list? The answers regarding performance enhancement seem to be both no and yes from the same sources. How common are TSH levels in the range of 2-5 mU/Liter among high level and hard training athletes? Does rest or an improved diet have an impact on these levels? All worthwhile questions which are not entirely answered.

The Wall Street Journal presents the side of the doctor who has diagnosed about 17% of the “Nike” athletes training with Salazar as having this condition. Carl Lewis was diagnosed with it before attempting to qualify for his fourth Olympics. The doc compares himself to “House” of TV fame as a mystery solver. I always considered House a sad story. He was addicted to Vicodan and usually needed at least five to seven attempts before he’d come up with the right diagnosis.

Flo Track presented a mature discussion on the topic with Lauren Fleshman saying that if only one doctor in the country was giving athletes the answer they wanted to hear, something just might be wrong with the picture.

I believe subclinical hypothyroidism exists. And I believe over training exists even more often. I’d recommend any athlete considering treating hypothyroidism while having a body fat of less than 12% should research the topic thoroughly and hope to soon find better statistics on training and endocrine hormone levels.

For all of us non-elite, non-professional athletes – make sure you pay attention to your body. Take the breaks you need, rest well, and eat well. And always avoid too much, too soon, too fast, too often, with too little rest. If you have signs of hypothyroidism, be sure to see your doctor.

References:

The treatment of Subclinical Hypothyroidism Is Seldom Necessary. Chu, J and Crapo, L. Journal of Clinical Endocrinology & Metabolism. JCEM. October 2001,

Flo Track discussion on WSJ article and Subclinical Hypothyroidism

U.S. Track’s Unconventional Physician in Wall Street Journal

Subclinical Hypothyroidism: An Update for Primary Care Physicians Vahab Fatourechi, MD Mayo Clin Proc >v.84(1); Jan 2009 >PMC2664572

 

The Beatles “I’m Down” (Cause my thyroxine is low & my TSH is high?)

 

Categories
Biology Science Sports Medicine Tendinopathy

The Science of Bone and Tendon Injuries (slideshare)

Perhaps one day I’ll break this up into 5 slideshares and 5 articles. But for now, here are the slides from a lecture presented at the Sports Medicine Section of the  American Podiatric Medical Associations Annual Scientific Conference.

I believe that basic science and research is an important component for advances clinical medicine. This lecture highlights some of that research from barebones systems biology to mechanotransduction. Cell mechanics, structure and biology are where the action is.

 

Slideshare: Overuse bone and tendon injuries – science and theories of tomorrow

Categories
Biology Sports Medicine

Achilles Tendon Stretches: Do’s and Don’ts (repost)

Achilles tendinitis prevention and recovery are issues faced by many runners. As anyone knows who has spent time on my web site, I am not a fan of excessive stretching for this problem. In individuals who are experiencing pain, I advise against the stair stretch, particularly if you’ve been trying it already for 6 weeks or more and found only more pain, and no improvement. In early cases of pain, I like to restrict stretching, than  graduate to the wall stretch, and then the wall stretch with a bent knee.

Roxanne Darling of Beachwalks with Rox does an excellent job of demonstrating a variety of stretches from the hard to the easy. For those without pain, you may carefully follow Rox’s example of the stair stretch if you’d like. If you have pain, skip that one for now and start with the straight leg, wall stretch and about 3 weeks – 4 weeks later add the bent knee portion. Read the article on Achilles Tendonitis (and Achilles Tendinopathy). A small portion of that article is summarized below. In the meantime, if you need a little downtime and some chilling, visit Beachwalks With Rox for words of wisdom, thought and relaxation.

Stretching With Rox

Achilles Tendonitis / Achilles Tendinopathy Brief Summary of Treatment

Full Text (Achilles Tendonitis)

Exercises to Avoid
Excessive stretching is not good for your Achilles tendon. The stretch that I most often recommend is the “wall stretch”. I do not recommend the “stair stretch”, the “incline stretch”, or the “put a towel around your feet and pull up until it hurts stretch”. If any of these are working for you, that’s great, you don’t need any advice. In most cases, for the patients I see, these stretches put too much tension on the already tender achilles tendon. Contracting the muscle when it is in a stretched position, as initial therapy of an injured achilles tendon is not a good thing. However, as seen in Rox’s video, she demonstrates some super stretches, and if you are not in acutely painful phase, you may cautiously give them a go. But, if you have found the stair stretches to be painful and counter productive, skip them, and look at the others.

Treatment Outline:

Relative rest
Cut back mileage
Lower intensity
Avoid hills, speedwork, plyometrics

Avoid over-stretching
Gentle stretch after warm-up
Start with Straight leg calf stretch, build up much later to bent leg, consider eccentric stretch later.
Ice Massage 10 to 20 minutes after exercise

NSAIDs (note: some recommend avoiding NSAIDS)
– Aleve, Motrin, Ibuprofen, etc. 10 – 14 days.

Check Running Shoes
– Replace if heel is worn
-Replace if excessive heel shock absorption (soft air sole cushion, excessive gel shock absorption)
Replace if shoe is excessively stiff at the “break point” (ball of foot).
Consider using a “heel lift”

Physical Therapy Modalities
HVGS (electrical stimulation)
Ultrasound
Exercise instruction: Strength and flexibility

Current Concepts of Achilles Tendonitis and Achilles Tendinopathy

While Achilles tendon problems are widespread, the terminology used to describe them is often inaccurate and is undergoing a significant transition. First to be precise we must consider where along the course of the tendon does the problem exist. This may be in one of three main areas:

1. Insertion
2. Musculo-tendinous Juncture
3. Non-insertional (main body of tendon)

While the term that most people use and that most individuals will search for on the web is “tendonitis”, most Achilles tendon problems could better be called a tendinopathy and more specifically a tendinosis and are a non-inflammatory problem of the tendon. Inflammatory cells are not found on microscopic examination.

Clinically there may be two differing entities in acute achilles tendinopathy:

Peritendonitis

o Inflammation in the tissue surrounding the tendon
o Often 2 – 6 cm above insertion

o Possible crepitus with long standing injury (paratenon with fibrin exudate)
o In chronic tendinopathy approximately 20% of the injured peritendinous area are scar forming myofibroblast cells.

Tendinosis
o Impairment of circulation with resulting damage to tendon structure
o Focal areas of tendon degeneration

Much future research and better understanding of these injuries is needed. In spite of the vagaries of scientific understanding of these entities a successful approach using training modification, stretching, strengthening and appropriate return to exercise may be undertaken. At this time there are few significant clinical studies with valid results for treatment. There is often disagreement on approach and much is likely to be changed in the future. At this point treatment and treatment recommendations for this problem remain an art practiced with varying degrees of success. When evaluating new research, it is hard to recommend major paradigm changes in thought and recommendations based on studies of fewer then 20 cases or even 50 cases.

Categories
Biology Medicine

Travelling, Running, and Starving – A New Approach To Your Circadian Rhythms (repost 2008)

For many people, long trips disturb the natural rhythms so much that normal functioning on both the physical and intellectual planes is impaired. Clearly, there is a need for some method to improve the travel experience and the race results for those on a tight schedule. First class? Sounds great, but isn’t practical and probably won’t get the job done.

Circadian rhythms may affect racing performance. Most world records have been set in the afternoon or evening rather than in the morning. It may be a matter of when the races are run, but it also may follow along with optimal body rhythms. Workouts seem easier in the afternoon, joints are stiffer in the morning, and some old lecture notes I have indicate that muscles are weakest at 8 AM & 8 PM and strongest at 5 PM. Body temperature reaches a peak around 5PM. (Spiking fevers when you are ill, do not spike in the morning, but late afternoon or evening.) Measured VO2 MAX is greater in the afternoon.

Adapting:

Suggestions

  • Start sleeping on the schedule of where you will be racing (or working).
  • If you can, train on the schedule of where you will be headed.
  • Get there early if you can, for optimal performance one day for every hour time difference. Otherwise follow all the other suggestions.
  • Melatonin
  • Bright lights for wake up time on new schedule and wake up also.
  • Eat lightly 2 days before travel, then start eating on the arrival schedule

The suggested eating change, of eating on the new arrival schedule comes as a result of a new study on circadian rhythms published in this weeks Science Magazine. The article notes that when food is readily available, circadian rhythms are greatly impacted by the light-dark cycle. If food is only available at night, the animal will shift its circadian rhythms to match the time when food is available. This led to studies of the gene clock Bmal1 and found that the dorsomedial hypothalamic nucleus seemed to impact the role of food and feeding on the circadian timing system (CTS). Light has previously been found to play a role via retinal ganglion cells containing melanopsin which generates signals to the suprachiasmatic nuclei (SCN) of the hypothalamus. The SCN then effects a tuning of the circadian rhythms via synaptic and humoral mechanisms. The studies described here were done on mice.

The authors conclusions were:

Our data indicate that there is an inducible clock in the DMH that can override the SCN and drive circadian rhythms when the animal is faced with limited food availability. Thus, under restricted feeding conditions, the DMH clock can assume an executive role in the temporal regulation of behavioral state. For a small mammal, finding food on a daily basis is a critical mission. Even a few days of starvation, a common threat in natural environments, may result in death. Hence, it is adaptive for animals to have a secondary “master clock” that can allow the animal to switch its behavioral patterns rapidly after a period of starvation to maximize the opportunity of finding food sources at the same time on following days.

The biological clock for mammals, clearly resides in the hypothalamus. In some insects and snails, the clocks seem to be located in the retina. In birds, the pineal gland has been thought to come into play, along with the hypothalamus. Photoreceptors are usually linked into the timing system, to synchronize the clock with the 24 hour day. Old studies showed light to be able to assist in resetting the clock by impacting genes, sleep patterns, alertness, and body temperature.

As we noted above, exercising on the new schedule, can also help. Recent research agrees with this as per the study “Scheduled exposures to a novel environment with a running-wheel differentially accelerate re-entrainment of mice peripheral clocks to new light–dark cycles (Yujiro Yamanaka, Sato Honma and Ken-ichi Honma Genes to Cells (2008) 13, 497-507)

A study from 2001 demonstrated the liver enzyme production could be shifted 10 hours within 2 days by altering feeding. (Science 19 January 2001: Vol. 291. no. 5503, pp. 490 – 493 Entrainment of the Circadian Clock in the Liver by Feeding. Karl-Arne Stokkan, Shin Yamazaki, Hajime Tei, Yoshiyuki Sakaki, Michael Menaker)

Larks and Owls
While we don’t have studies to cite here, others have noted that some people are better at staying up late than others, while others are happy to wake up at 5 or 6am, but can’t stay up to party, play MMORPGs, or text their buddies in the middle of the night.

Some feel that it is easier for Larks to travel west to east and for owls to travel from east to west. The larks have little trouble staying up late, and have probably already shifted in part to the western time zone.

Categories
Biology Medicine Sports Medicine

Viva La Différence: Exercising Sitting Down vs. Standing Up (repost 2007)

The New York Times had an article today which discusses how bicyclists come in all shapes and sizes. Gina Kolata mentions that that many cyclists did not meet her conception of what an in shape cyclist would look like. The reality is that runners come in all shapes, sizes and ages also and this can be seen at many marathon events. The other part of the reality is that elites among both runners and cyclists have different morphological characteristics including a lower body fat content, higher MVO2 and various other items.

But, there is hope for all of us. George Sheehan once said “We are all athletes, some of us are in training and some are not.”

“When I first got into cycling, I would see cyclists and say, ‘O.K., that’s not what I perceive a cyclist to be,’ ” said Michael Berry, an exercise physiologist at Wake Forest University. Dr. Berry had been a competitive runner, and he thought good cyclists would look like good runners — rail-thin and young.

But, Dr. Berry added, “I quickly learned that when I was riding with someone with a 36-inch waist, I could be looking at the back of their waist when they rode away from me.”

He came to realize, he said, that cycling is a lot more forgiving of body type and age than running. The best cyclists going up hills are those with the best weight-to-strength ratio, which generally means being thin and strong. But heavier cyclists go faster downhill. And being light does not help much on flat roads.

But on the other hand, there are differences that make cycling a bit more forgiving:

“In running, when you see someone who is obviously overweight, they will be in trouble,” Dr. Hagberg said. “The more you weigh, the more the center of gravity moves and the more energy it costs. But in cycling, there are different aerodynamics — your center of gravity is not moving up and down.”

The difference between cycling and running is like the difference between moving forward on a pogo stick and rolling along on wheels. And that is why Robert Fitts, an exercise physiologist at Marquette University who was a competitive runner, once said good runners run so smoothly they can almost balance an apple on their heads.

Categories
Aging Biology

Sunscreens: Hype and Reality (repost 2007)

Sunscreens are helpful in reducing exposure to the harmful effects of UVA and UVB. These types of solar radiation contribute to the development of premature skin aging, wrinkling and both malignant and non-malignant skin cancer. Basal Cell Cancer and Melanoma, among other types of skin cancer has an increased incidence in sun exposed individuals. Some have estimated that only about 20% of melanomas are related to skin cancer. Other disfiguring cancers, including basal cell though seem to have a very high correlation with sun exposure.

Melanoma has multiple risk factors which include fair complexion, blonde or red hair color, blue, blue/green eye color (skin phototypes I/II), total sun exposure and a history of blistering sun burns. Genetics, or inherited risks may include genetically linked disorders such as the dysplastic nevus syndrome. The overall risk has increased dramatically over the last 50 years or so. In 1935 the lifetime risk for developing melanoma was 1:1500 in 1935 and grew to 1:74 in 2000. It is estimated that it will grow to 1:50 in 2010. It is estimated that over 53,000 new cases of melanoma are diagnosed now each year. A good number of these are diagnosed at an early stage.

Today’s New York Times implicitly criticizes Neutrogenia for a campaign in which they imply that not using sunscreen and their products is akin to suicide. It includes a clip in which a woman holds up a photo and says “My sister killed herself. She died of skin cancer.” Since melanoma can occur in people with little sun exposure and the majority of it may, this is in bad taste. There isn’t even a campaign that strong for lung cancer sponsored by Nicorette.

Continue reading “Sunscreens: Hype and Reality (repost 2007)”