Wednesday, January 28, 2009
Saturday, December 6, 2008
I have been considering how to write on nutrition. One of the biggest issues in the public health arena is obesity. We all know that personal responsibility and social responsibility are two arms of the same issue. Since, education is the preferred tool for creating greater personal responsibility, policy was aimed at increasing nutritional education. However, as many of us know, rarely do we eat correctly. With this in mind current policy is aimed at changing the environment. This is seen in the movement to remove unhealthy snacks in the school vending machines, smaller portions served at restaurants, healthy food choices at places like McDonald's, and the willingness for restaurants to accommodate low fat and low salt diets.
But, there is more to the story than simply too much food. Marion Nestle, MD, MPH writes and lectures extensively on the politics of food. I feel that a lecture that she gave at Google in 2007 serves as a very good general overview as to what has happened in the food industry that has made significant changes in the consumption of food. The video is about an hour long but, is worth listening to (in smaller portions if you prefer).
But, there is more to the story than simply too much food. Marion Nestle, MD, MPH writes and lectures extensively on the politics of food. I feel that a lecture that she gave at Google in 2007 serves as a very good general overview as to what has happened in the food industry that has made significant changes in the consumption of food. The video is about an hour long but, is worth listening to (in smaller portions if you prefer).
Thursday, October 9, 2008
Specificity of Training or Training a Bulldog
My boss’s bull dog was originally bred to bait bulls. This was a popular entertainment in the Middle Ages, and the English standard bull dog is uniquely designed for this activity. The English bulldog was able to grab the bull by the nose or lip and hang on for dear life. The short neck and particular bite facilitated the dog’s ability to hang on. The upturned nose allows the dog to breathe as the bull’s nose or lip began to swell. The set of the eyes and the strategically placed wrinkles and jowls allows for yucky fluids to drain away from the dog’s eyes and channel away from the mouth. The dog’s build facilitates its ability to jump and catch the nose. The wide stance and short legs helps the dog stay low and out of reach of the horns. So, as a personal trainer I would need to use the principle of Specificity of training to design an efficient training program for Misha, the Bulldog.
Functional training is a popular buzz phrase in the fitness industry. Often times it is interpreted as “balance and core” training. But actually it is training that is specific to the movements of specific activities or lifestyle. So, would the functional training of Misha, my boss’s bulldog, be the same as the functional training of a Newfoundland dog? Both dogs are sturdy and robust. Both can pull stuff in a cart. Both breeds drool. But, when a needs assessment is done, it is found that Newfoundlands make terrible bull baiters and bull dogs aren’t exactly on everyone’s short list for water rescue.
Specificity of training says that I should increase the strength and endurance of Misha’s jaws, increase her ability to withstand being shaken and tossed about while hanging in the air, increase her sprint and jump ability while training her bite timing. The other day I began her training: We used a favorite pull toy and she latched on and I hauled her into the air until her feet were in the air. I shook her back and forth while she growled and hung on. This lasted all of 20 seconds and I set her down. We were both pooped. (Misha weighs around 68 pounds.) The next day all she did was rest.
Now, there is no way that I could do this with a 120-150 pound Newfoundland. Newfees like to play tug also bu
t their version is to drag you around the yard. This is good because these dogs, historically, haul carts, wood for boat construction, nets, drowning seamen, ropes to shore, and anything else you can think of. Therefore the best training program for them is to strengthen their long slow endurance levels and swim them a lot. (I wouldn’t recommend swimming a bulldog nearly as much. The shorter hair and lack of webbing between their toes can make a bulldog a poor swimmer.)Humans are similar to dogs. Well… we don’t tend to drool as much, but, we can pull stuff, we can swim, some of us are pretty robust, and some of us use a lot of bull. But, we have different needs. Some of us want to lose weight, some want to get stronger, some want to get “toned,” and some of us must want to become circus acts. (I have seen some trainers use equipment designed for “functional” training in very unique ways.) What it all boils down to is that an exercise program has to be based on sound scientific exercise principles. The ideal program is designed to take advantage of certain physical attributes (or to correct posture and/or joint motion) and to meet the goals of the individual. Exercise programs are individualized to increase performance levels and general health. A basket ball player does not do the same program as a gymnast, and neither does my 83 year old Aunt. Specificity of training determines the outcome of an exercise program.
Saturday, September 13, 2008
Appetite: Who let the dog out?
My boss has a new dog. She is a bulldog and is a great addition to the place. She spends most of her time prone, except for those times when her nose is to the ground looking for eats. She puts in an awful lot of effort into eating, snorting her way through her meal. (Actually, I think she is inhaling like a vacuum.) She has severe under bite so, she has to work extra hard. When she is done eating she has to lay down for a bit. Sound familiar?
Sedentary bulldogs run the risk of becoming overweight from over feeding. Like bulldogs we can be just as sedentary and this can lead to an increased risk of health issues. Bulldogs eat because it gives them pleasure. Humans have more complex reasons for eating and pleasure is just one of many. Bulldogs have humans who determine what and when they eat (discounting children who drop food). Since a bulldog is so persistent and has that soulful "poor me" look it can be difficult not to give in and feed them a “treat.” We have food guardians only when we are small children (discounting children who manage to control their parents). However, unlike a bulldog, we can get our own food without much difficulty once we are past the age of three.
We can even override our own internal feeding mechanism while bull dogs can’t. We have a hormonal mechanism that turns on and off the desire to eat. My boss’s dog, Misha, can’t do this, she is always willing to eat, and will continue to eat until she throws up and starts all over. (I think that this is a dog’s version of binge and purge.) Humans, through a variety of tactics (binge and purge being one of them), can manipulate the appetite mechanism.
The center for this appetite control axis is in the hypothalamus. (For some this is the true Axis of Evil.) Our hypothalamus has two categories of hormones that it releases that control eating: The orexigenic peptides that stimulate appetite and the anorexigenic peptides that suppress appetite. But wait, there’s more: Our gut also has hormones that it releases to signal the hypothalamus that it is time to stop eating, time to eat, give me more, give me less, I’m still not finished, and excuse me are you going to finish that? Then there are hormones that are released from adipose tissue (fat) cells. The main hormone from fat cells signals the hypothalamus to release anorexigenic hormones, in effect putting the brakes on eating.
When we try to lose weight we declare war on the Axis of Evil. Unfortunately, as in all wars, innocents get hurt. The delicate balance that is held by a properly working chemical feedback loop is destroyed. Dieting, which is all about denial, changes this balance, the appetite mechanism gets confused, the body downsizes the production of un-needed proteins (hormones), the brain gets grouchy, and then we eat like Misha, blow the “diet,” and get the h*ll out of Dodge.
Ah, but since we are humans and not bull dogs, we can change this scenario. We can choose to eat four to five small meals per day. We can choose to eat healthy choices. We can choose to exercise adequately. We can choose to alter our life style to accommodate healthy changes and re-set our out of whack systems. We can choose to change or live a dog’s life (which might not be all bad…).
Sedentary bulldogs run the risk of becoming overweight from over feeding. Like bulldogs we can be just as sedentary and this can lead to an increased risk of health issues. Bulldogs eat because it gives them pleasure. Humans have more complex reasons for eating and pleasure is just one of many. Bulldogs have humans who determine what and when they eat (discounting children who drop food). Since a bulldog is so persistent and has that soulful "poor me" look it can be difficult not to give in and feed them a “treat.” We have food guardians only when we are small children (discounting children who manage to control their parents). However, unlike a bulldog, we can get our own food without much difficulty once we are past the age of three.
We can even override our own internal feeding mechanism while bull dogs can’t. We have a hormonal mechanism that turns on and off the desire to eat. My boss’s dog, Misha, can’t do this, she is always willing to eat, and will continue to eat until she throws up and starts all over. (I think that this is a dog’s version of binge and purge.) Humans, through a variety of tactics (binge and purge being one of them), can manipulate the appetite mechanism.
The center for this appetite control axis is in the hypothalamus. (For some this is the true Axis of Evil.) Our hypothalamus has two categories of hormones that it releases that control eating: The orexigenic peptides that stimulate appetite and the anorexigenic peptides that suppress appetite. But wait, there’s more: Our gut also has hormones that it releases to signal the hypothalamus that it is time to stop eating, time to eat, give me more, give me less, I’m still not finished, and excuse me are you going to finish that? Then there are hormones that are released from adipose tissue (fat) cells. The main hormone from fat cells signals the hypothalamus to release anorexigenic hormones, in effect putting the brakes on eating.
When we try to lose weight we declare war on the Axis of Evil. Unfortunately, as in all wars, innocents get hurt. The delicate balance that is held by a properly working chemical feedback loop is destroyed. Dieting, which is all about denial, changes this balance, the appetite mechanism gets confused, the body downsizes the production of un-needed proteins (hormones), the brain gets grouchy, and then we eat like Misha, blow the “diet,” and get the h*ll out of Dodge.
Ah, but since we are humans and not bull dogs, we can change this scenario. We can choose to eat four to five small meals per day. We can choose to eat healthy choices. We can choose to exercise adequately. We can choose to alter our life style to accommodate healthy changes and re-set our out of whack systems. We can choose to change or live a dog’s life (which might not be all bad…).
Resistance Training and Type 2 Diabetes
Diabetes is a disease that involves the body’s ability to properly clear glucose from the blood stream. When excess glucose, or blood sugar, builds up in the body serious problems can result. These problems affect kidneys, eyes, nerves gums and teeth. A very serious problem that can develop is cardiovascular disease. A diabetic’s risk for heart attack is the same as a person who has already had an attack. (1) This risk applies to both men and women. To moderate this risk it important to keep blood pressure and blood fat levels under control.
The regulation of blood glucose requires a delicate balance between several signaling proteins that bring glucose in and out of the cell. The hormone insulin begins a cascade of events that lead to entry of blood glucose into the cell. If the cascade is inhibited at any of the many steps the glucose clearance rate is slowed. This causes a rise in blood sugar levels that is so detrimental to human health.
One glucose transport protein that has been looked at is called GLUT4. This protein is located inside the cell. With the stimulation of insulin through a series of steps, GLUT4 is sent (translocated) to the cell membrane to carry glucose molecules into the cell. If the cell does not have a high ratio of these transporters then the cell may decrease the number of receptor sites for insulin and become insulin intolerant. This condition (also known as insulin resistance) is a precursor to diabetes type 2. Diabetes type 2 is characterized by insulin resistance and a relative decrease in the effectiveness of insulin. There is also a genetic component with type 2, however, lifestyle choices can inhibit or slow the development of the disease. (2)
Epidemiologically type 2 diabetes is a major health concern world -wide. Type 2 diabetes was rarely seen in children but, now it is seen world -wide in both children and adults (mostly in low and middle income countries). The World Health Organization estimates that in 2005 over 1.1 million people died of the disease. There is a projection of a 50% increase in deaths in the next ten years in low to middle income countries, and in upper income countries an 80% increase between 2006-2015.(3).
Exercise is a common method used to manage diabetes type 2. Much of the research on type 2 diabetes and exercise has been concerned with aerobic exercise. Walking is the easiest aerobic exercise to perform. Unfortunately, many overweight individuals find walking to be difficult on joints and many abandon the activity. Resistance training (RT) is a good alternative. Research has shown that RT can help maintain glucose clearance rates.
Muscle is one of the main repositories of blood sugar. (The liver is the other one.) There are two main muscle fiber types; slow twitch type one (T1) and fast twitch type two (T2). Both muscle types use a mix of glucose and fats, however, type one fibers have the ability to use more oxygen and thus tend towards fat as a fuel source. Type 2 fibers are the muscles that are used to initiate movements and fast actions. Their main fuel mix is predominately glucose. How does this affect blood sugar levels in a type 2 diabetic?
Research has shown that overweight individuals have different ratios of muscle fiber types than lean individuals. Tanner et al in 2002 determined that obese women possessed lower levels of T1 (slow twitch oxidative) fibers than lean. This means that their levels of T2 fibers (fast twitch, glycolytic) were relatively higher. (The authors speculate that this may be why it is difficult for obese individuals to lose weight and to keep it off. If you have a lower percentage of fat burning muscle fibers then it can be difficult to burn enough calories through aerobic exercise to lose weight and to keep it off.)(4) Michael Gaster et al found that in overweight and obese individuals there is a lower ratio of GLUT4 in T1 muscle than in lean individuals’ T1 muscle. This means that blood sugar clearance is much lower. In type 2 diabetics the GLUT4 ratio is even lower in T1 muscle than in overweight non-diabetics. (5) (Remember the process that blood sugar needs to enter into the muscle cells? Insulin attaches to the cell receptor and causes a cascade of actions that result in the glucose being transported into the cell via the transporter called GLUT4. These transporters have to be present in the cell at a certain ratio or level. )
What does this mean? It means that those who are diabetic and overweight may have difficulty using aerobic exercise as a means to weight loss and maintaining blood glucose levels. But, remember those type 2 muscle fibers? There are quite a few studies that have shown that resistance training can improve glucose regulation. The common belief is that the increase in lean mass was the reason for this improvement. This may not be the case.
Ben Yaspelkis and his associates found that in rat skeletal muscle GLUT4 signaling was improved with resistance training. This is due to an increase in signaling proteins and GLUT4 levels in T2 muscle fibers. Two sets of rats were placed on two exercise protocols; 1. aerobic exercise and 2. resistance exercise. Aerobic rats ran on a motorized treadmill for 12 weeks three times per week. Resistance rats were placed on a RT program of three sets of 10 repetitions with 75% of their one repetition maximum three times per week for 12 weeks. (He made an ingenious rat squat machine.)
Both sets of rats had improved glucose clearance. The aerobic rats showed improvements in lower leg muscle used for running. The RT rats showed better glucose uptake in the upper leg used for squatting. (The resistance trained rats had glucose transport improvements without an increase in muscle size.) The results are not surprising since there is quite a body of literature supporting aerobic exercise as an effective way to improve glucose clearance rates in both type2 diabetics and healthy populations. There is a smaller number of studies that show RT to have a positive effect on clearance rates and those studies that have been done have not looked extensively at the mechanism for improvement. Yaspelkis et al have shown that the improvements in clearance is due to more effective activation of the insulin stimulated signaling cascade in resistance trained muscle. (6)
Insulin sensitivity in older Hispanic men has been found to be improved after 16 weeks of resistance training. Naomi Brooks et al report that after 35 minutes three days per week of 16 weeks of resistance training that there were improvements in muscle quality, whole body insulin sensitivity, decreased inflammation, and better metabolic control as a result of the improvements. (7) Dunstan et al also found that in overweight men and women aged 60-80 years high intensity weight training plus moderate weight loss is effective in improving blood sugar control. (8) Resistance training can be an effective alternative to aerobic exercise for diabetes type 2 patients especially for older individuals.
Patients with complications from diabetes type 2 such as, peripheral neurological problems, cardiovascular disease, retinopathy, autonomic neuropathy (affecting the nerves to the heart), and high blood pressure need to use lower intensity resistance training. The American College of Sports Medicine recommends that blood glucose levels be checked prior to and after exercise. If glucose levels are >250 ml/dl then exercise needs to be postponed until levels are normalized. If glucose levels are <100 ml/dl then a snack should be eaten prior (about 10-20 grams of easily absorbed carbohydrate). Good shoes are mandatory for a diabetic due to circulation issues. Feet should be checked regularly and kept clean. A diabetic patient should exercise with a partner or under supervision in case of an emergency. (9)
Check with your physician before undertaking an exercise program.
1. http://www.diabetes.niddk.nih.gov/dm/pubs/type1and2/what.htm
2. http://www.healthinsite.gov.au/topics/Types_of_Diabetes
3. http://www.who.int/features/chronic_disease/en/index.html
4. Tanner, C.J., Barakat, H.A., Dohm,G.L., Pories, W.J., MacDonald, K.G., Cunningham, P.R., Swanson, M.S., and Houmard, J.A. “Muscle fiber type is associated with obesity and weight loss.” Am. J. Physiol Endocrinol Metab, 282:E1191-E1196, 1002.
5. Gaster, M., Stacher,P., Beck-Nielson, H., Schrader H.D., and Handberg, A. “Glut4 is reduced in slow fibers of type 2 diabetic patients.” Diabetes, June 2001, vol 50.
6. Yaspelkis, Ben. “Resistance training improves insulin signaling and action in skeletal muscle.” Exer. Sport Sci. Rev., Vol. 43, pp. 42-46, 2006.
7. Brooks,N., Layne, J.E., Gordon, P.T., Roubenoff, R., Nelson, M.E., Castaneda-Scappa, C. “Strength training improves muscle quality and insulin sensitivity in Hispanic older adults with type 2 diabetes.” Int. J Med Sci, 4(1):19-27, 2007.
8. Dunstan, D.W., Daly, R.M., Owen, N., Jolley, D., de Courten, M., Shaw, J., and Zimmet, P. “High intensity resistance training improves glycemic control in older patients with type 2 diabetes.” Diabetes Care, 25(10): 1729-1736, 2002.
9. ACSM’s Resource Manual for Guidelines for Exercise Testing and Prescription, 5th ed. American College of Sports Medicine, 2006
The regulation of blood glucose requires a delicate balance between several signaling proteins that bring glucose in and out of the cell. The hormone insulin begins a cascade of events that lead to entry of blood glucose into the cell. If the cascade is inhibited at any of the many steps the glucose clearance rate is slowed. This causes a rise in blood sugar levels that is so detrimental to human health.
One glucose transport protein that has been looked at is called GLUT4. This protein is located inside the cell. With the stimulation of insulin through a series of steps, GLUT4 is sent (translocated) to the cell membrane to carry glucose molecules into the cell. If the cell does not have a high ratio of these transporters then the cell may decrease the number of receptor sites for insulin and become insulin intolerant. This condition (also known as insulin resistance) is a precursor to diabetes type 2. Diabetes type 2 is characterized by insulin resistance and a relative decrease in the effectiveness of insulin. There is also a genetic component with type 2, however, lifestyle choices can inhibit or slow the development of the disease. (2)
Epidemiologically type 2 diabetes is a major health concern world -wide. Type 2 diabetes was rarely seen in children but, now it is seen world -wide in both children and adults (mostly in low and middle income countries). The World Health Organization estimates that in 2005 over 1.1 million people died of the disease. There is a projection of a 50% increase in deaths in the next ten years in low to middle income countries, and in upper income countries an 80% increase between 2006-2015.(3).
Exercise is a common method used to manage diabetes type 2. Much of the research on type 2 diabetes and exercise has been concerned with aerobic exercise. Walking is the easiest aerobic exercise to perform. Unfortunately, many overweight individuals find walking to be difficult on joints and many abandon the activity. Resistance training (RT) is a good alternative. Research has shown that RT can help maintain glucose clearance rates.
Muscle is one of the main repositories of blood sugar. (The liver is the other one.) There are two main muscle fiber types; slow twitch type one (T1) and fast twitch type two (T2). Both muscle types use a mix of glucose and fats, however, type one fibers have the ability to use more oxygen and thus tend towards fat as a fuel source. Type 2 fibers are the muscles that are used to initiate movements and fast actions. Their main fuel mix is predominately glucose. How does this affect blood sugar levels in a type 2 diabetic?
Research has shown that overweight individuals have different ratios of muscle fiber types than lean individuals. Tanner et al in 2002 determined that obese women possessed lower levels of T1 (slow twitch oxidative) fibers than lean. This means that their levels of T2 fibers (fast twitch, glycolytic) were relatively higher. (The authors speculate that this may be why it is difficult for obese individuals to lose weight and to keep it off. If you have a lower percentage of fat burning muscle fibers then it can be difficult to burn enough calories through aerobic exercise to lose weight and to keep it off.)(4) Michael Gaster et al found that in overweight and obese individuals there is a lower ratio of GLUT4 in T1 muscle than in lean individuals’ T1 muscle. This means that blood sugar clearance is much lower. In type 2 diabetics the GLUT4 ratio is even lower in T1 muscle than in overweight non-diabetics. (5) (Remember the process that blood sugar needs to enter into the muscle cells? Insulin attaches to the cell receptor and causes a cascade of actions that result in the glucose being transported into the cell via the transporter called GLUT4. These transporters have to be present in the cell at a certain ratio or level. )
What does this mean? It means that those who are diabetic and overweight may have difficulty using aerobic exercise as a means to weight loss and maintaining blood glucose levels. But, remember those type 2 muscle fibers? There are quite a few studies that have shown that resistance training can improve glucose regulation. The common belief is that the increase in lean mass was the reason for this improvement. This may not be the case.
Ben Yaspelkis and his associates found that in rat skeletal muscle GLUT4 signaling was improved with resistance training. This is due to an increase in signaling proteins and GLUT4 levels in T2 muscle fibers. Two sets of rats were placed on two exercise protocols; 1. aerobic exercise and 2. resistance exercise. Aerobic rats ran on a motorized treadmill for 12 weeks three times per week. Resistance rats were placed on a RT program of three sets of 10 repetitions with 75% of their one repetition maximum three times per week for 12 weeks. (He made an ingenious rat squat machine.)
Both sets of rats had improved glucose clearance. The aerobic rats showed improvements in lower leg muscle used for running. The RT rats showed better glucose uptake in the upper leg used for squatting. (The resistance trained rats had glucose transport improvements without an increase in muscle size.) The results are not surprising since there is quite a body of literature supporting aerobic exercise as an effective way to improve glucose clearance rates in both type2 diabetics and healthy populations. There is a smaller number of studies that show RT to have a positive effect on clearance rates and those studies that have been done have not looked extensively at the mechanism for improvement. Yaspelkis et al have shown that the improvements in clearance is due to more effective activation of the insulin stimulated signaling cascade in resistance trained muscle. (6)
Insulin sensitivity in older Hispanic men has been found to be improved after 16 weeks of resistance training. Naomi Brooks et al report that after 35 minutes three days per week of 16 weeks of resistance training that there were improvements in muscle quality, whole body insulin sensitivity, decreased inflammation, and better metabolic control as a result of the improvements. (7) Dunstan et al also found that in overweight men and women aged 60-80 years high intensity weight training plus moderate weight loss is effective in improving blood sugar control. (8) Resistance training can be an effective alternative to aerobic exercise for diabetes type 2 patients especially for older individuals.
Patients with complications from diabetes type 2 such as, peripheral neurological problems, cardiovascular disease, retinopathy, autonomic neuropathy (affecting the nerves to the heart), and high blood pressure need to use lower intensity resistance training. The American College of Sports Medicine recommends that blood glucose levels be checked prior to and after exercise. If glucose levels are >250 ml/dl then exercise needs to be postponed until levels are normalized. If glucose levels are <100 ml/dl then a snack should be eaten prior (about 10-20 grams of easily absorbed carbohydrate). Good shoes are mandatory for a diabetic due to circulation issues. Feet should be checked regularly and kept clean. A diabetic patient should exercise with a partner or under supervision in case of an emergency. (9)
Check with your physician before undertaking an exercise program.
1. http://www.diabetes.niddk.nih.gov/dm/pubs/type1and2/what.htm
2. http://www.healthinsite.gov.au/topics/Types_of_Diabetes
3. http://www.who.int/features/chronic_disease/en/index.html
4. Tanner, C.J., Barakat, H.A., Dohm,G.L., Pories, W.J., MacDonald, K.G., Cunningham, P.R., Swanson, M.S., and Houmard, J.A. “Muscle fiber type is associated with obesity and weight loss.” Am. J. Physiol Endocrinol Metab, 282:E1191-E1196, 1002.
5. Gaster, M., Stacher,P., Beck-Nielson, H., Schrader H.D., and Handberg, A. “Glut4 is reduced in slow fibers of type 2 diabetic patients.” Diabetes, June 2001, vol 50.
6. Yaspelkis, Ben. “Resistance training improves insulin signaling and action in skeletal muscle.” Exer. Sport Sci. Rev., Vol. 43, pp. 42-46, 2006.
7. Brooks,N., Layne, J.E., Gordon, P.T., Roubenoff, R., Nelson, M.E., Castaneda-Scappa, C. “Strength training improves muscle quality and insulin sensitivity in Hispanic older adults with type 2 diabetes.” Int. J Med Sci, 4(1):19-27, 2007.
8. Dunstan, D.W., Daly, R.M., Owen, N., Jolley, D., de Courten, M., Shaw, J., and Zimmet, P. “High intensity resistance training improves glycemic control in older patients with type 2 diabetes.” Diabetes Care, 25(10): 1729-1736, 2002.
9. ACSM’s Resource Manual for Guidelines for Exercise Testing and Prescription, 5th ed. American College of Sports Medicine, 2006
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