Exercise and blood glucose levels: Insulin and glucose responses to exercise

The notion that exercise reduces blood glucose levels is widespread. That notion is largely incorrect. Exercise appears to have a positive effect on insulin sensitivity in the long term, but also increases blood glucose levels in the short term. That is, exercise, while it is happening, leads to an increase in circulating blood glucose. In normoglycemic individuals, that increase is fairly small compared to the increase caused by consumption of carbohydrate-rich foods, particularly foods rich in refined carbohydrates and sugars.The figure below, from the excellent book by Wilmore and colleagues (2007), shows the variation of blood insulin and...

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Compensatory adaptation as a unifying concept: Understanding how we respond to diet and lifestyle changes

Trying to understand each body response to each diet and lifestyle change, individually, is certainly a losing battle. It is a bit like the various attempts to classify organisms that occurred prior to solid knowledge about common descent. Darwin’s theory of evolution is a theory of common descent that makes classification of organisms a much easier and logical task.Compensatory adaptation (CA) is a broad theoretical framework that hopefully can help us better understand responses to diet and lifestyle changes. CA is a very broad idea, and it has applications at many levels. I have discussed CA in the context of human behavior in general (Kock, 2002), and human behavior toward communication technologies (Kock, 2001; 2005; 2007). Full references and links are at the end of this post.CA is all...

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Love your Electricals and set them free for Recycle Week

So if your old man has reached the heights of being follicly challenged and doesn't know what to do with his redundant hair clippers or you're fed up of tripping over the broken strimmer in the shed, this is the week to go forth and show them the door for good.Not "him indoors" of course, but his truckload of useless stuff!Yes, it's Recycle Week 2010, which runs until 27th June, and this year's theme is Love your Electricals, encouraging us to finally part with our useless gadgets. That's anything with a battery or plug and could include broken toasters and kettles, old mobile phones or disused power tools, all of which could either be reused or recycled.But did you know getting rid of this stuff is actually easier said than done! According to a survey carried out  by ICM Research, many...

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What about some offal? Boiled tripes in tomato sauce

Tripe dishes are made with the stomach of various ruminants. The most common type of tripe is beef tripe from cattle. Like many predators, our Paleolithic ancestors probably ate plenty of offal, likely including tripe. They certainly did not eat only muscle meat. It would have been a big waste to eat only muscle meat, particularly because animal organs and other non-muscle parts are very rich in vitamins and minerals.The taste for tripe is an acquired one. Many national cuisines have traditional tripe dishes, including the French, Chinese, Portuguese, and Mexican cuisines – to name only a few. The tripe dish shown in the photo below was prepared...

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Pretty faces are average faces: Genetic diversity and health

Many people think that the prettiest faces are those with very unique features. Generally that is not true. Pretty faces are average faces. And that is not only because they are symmetrical, even though symmetry is an attractive facial trait. Average faces are very attractive, which is counterintuitive but makes sense in light of evolution and genetics.The faces in the figure below (click to enlarge) are from a presentation I gave at the University of Houston in 2008. The PowerPoint slides file for the presentation is available here. The photos were taken from the German web site Beautycheck.de. This site summarizes a lot of very interesting...

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Soccer as play and exercise: Resistance and endurance training at the same time

Many sports combine three key elements that make them excellent fitness choices: play, resistance exercise, and endurance exercise; all at the same time. Soccer is one of those sports. Its popularity is growing, even in the US! The 2010 FIFA World Cup, currently under way in South Africa, is a testament to that. It helps that the US team qualified and did well in its first game against England.Pelé is almost 70 years old in the photo below, from Wikipedia. He is widely regarded as the greatest soccer player of all time. But not by Argentineans, who will tell you that Pelé is probably the second greatest soccer player of all time, after Maradona.Even...

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Fructose in fruits may be good for you, especially if you are low in glycogen

Excessive dietary fructose has been shown to cause an unhealthy elevation in serum triglycerides. This and other related factors are hypothesized to have a causative effect on the onset of the metabolic syndrome. Since fructose is found in fruits (see table below, from Wikipedia; click to enlarge), there has been some concern that eating fruit may cause the metabolic syndrome.Vegetables also have fructose. Sweet onions, for example, have more free fructose than peaches, on a gram-adjusted basis. Sweet potatoes have more sucrose than grapes (but much less overall sugar), and sucrose is a disaccharide derived from glucose and fructose. Sucrose...

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Cortisol, stress, excessive gluconeogenesis, and visceral fat accumulation

Cortisol is a hormone that plays several very important roles in the human body. Many of these are health-promoting, under the right circumstances. Others can be disease-promoting, especially if cortisol levels are chronically elevated.Among the disease-promoting effects of chronically elevated blood cortisol levels are that of excessive gluconeogenesis, causing high blood glucose levels even while a person is fasting. This also causes muscle wasting, as muscle tissue is used to elevate blood glucose levels.Cortisol also seems to transfer body fat from subcutaneous to visceral areas. Presumably cortisol promotes visceral fat accumulation to facilitate...

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Time for an ASAP pledge

Yesterday I received a call from Baglady.  Not just any old baglady but Shirley Lewis, the fabulous campaigner from Northern Ireland who's encouraging folk everywhere to live ASAP - As Sustainably As Possible.  And what better time to get involved as Baglady has just launched ASAP Pledge Fortnight.The highlight of the awareness campaign is ASAP Pledge Week, which starts on Monday 14th June and leads up to ASAP Pledge Day when, on June 21st, children from Northern Ireland will take their pledges to the Northern Ireland Assembly at Stormont to ask politicians to join in and support living ASAP.Baglady is asking you to be involved too,...

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Niacin turbocharges the growth hormone response to anaerobic exercise: A delayed effect

Niacin is also known as vitamin B3, or nicotinic acid. It is an essential vitamin whose deficiency leads to pellagra. In large doses of 1 to 3 g per day it has several effects on blood lipids, including an increase in HDL cholesterol and a marked decreased in fasting triglycerides. Niacin is also a powerful antioxidant.Among niacin’s other effects, when taken in large doses of 1 to 3 g per day, is an acute elevation in growth hormone secretion. This is a delayed effect, frequently occurring 3 to 5 hours after taking niacin. This effect is independent of exercise.It is important to note that large doses of 1 to 3 g of niacin are completely...

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The most rubbish hotel in Rome

So who wants to stay in a hotel like this?   Well, supermodel and eco warrior Helena Christensen for one!Commissioned by Corona's Save the Beach campaign for World Environment Day, this pop-up rubbish hotel in Rome was created by German artist HA Schult to highlight the importance of preserving Europe's beaches. And it's built almost entirely from rubbish collected from the sands of our wonderful continent.Although this two storey construction, which surprisingly can sleep up to 10 people, will only be in open until Monday 7 June, its message will last for longer.  The Save the Beach campaign is inviting people across Europe to...

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Growth hormone secretion drops with age, but not exactly in the way you would expect

Many people assume that growth hormone secretion drops with age in a somewhat linear fashion, as implied by this diagram. This assumption probably stems from attempts to model growth hormone variations with linear regression algorithms. This assumption is wrong.Actual plots of growth hormone secretion patterns, with age on the horizontal axes, tell a different story. See, for example, the graphs below, from professionalmuscle.com. They match the graphs one sees in empirical academic papers. The graphs below (click to enlarge) are particularly good at highlighting some interesting patterns of variation.On the left side, bar charts show secretion...

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Cortisol response to stress is much more elevated with ingestion of glucose than with protein or fat

Cortisol is a hormone that does a number of different things; a jack of all trades among hormones, so to speak. It tells the liver to produce glucose, preventing hypoglycemia. It also tells the liver to synthesize glycogen, which is in some ways the opposite of producing glucose. It tells the stomach to secret gastric acid. It is an anti-diuretic hormone. It suppresses the immune system, which is why it is frequently used to reduce inflammation, and treat allergies and various autoimmune diseases. It jump-starts an increase in free fatty acids in circulation, thus helping provide an important source of energy for endurance exercise.Cortisol,...

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