Friday, October 29, 2010

Why You Need Interval Training for Both Speed and Endurance

To have great endurance for any sport, you have to do interval training: short bursts of moving almost as fast as you can, slowing down until you regain your breathe and then repeating these all-out efforts a number of times.

The old theory was that lactic acid makes the muscles more acidic which causes them to hurt and burn and interferes with their ability to contract, so you feel tired. George Brooks of the University of California/Berkeley has shown that lactic acid buildup in muscles does not make muscles tired and can make muscle contract more efficiently, which increases endurance. This research contradicts what many instructors teach in their exercise classes. When you exercise, your muscles burn sugar, protein and fat in the presence of oxygen to produce energy. If you exercise so intensely that you become very short of breath and your muscles can't get enough oxygen, lactic acid accumulates in your muscle fibers.

When you exercise, muscles need to get a lot of oxygen to turn all food sources into energy. In fact, the limiting factor to how fast you can move in sports competition is the time that it takes to move oxygen from the bloodstream in your lungs into your muscles. When you exercise so intensely that your muscles cannot get all the oxygen they need to turn sugar into energy, the series of chemical reactions slows down and lactic acid accumulates in muscles and spills over into the bloodstream.

Since lactic acid is an acid, the acidity causes muscles to burn and you have to slow down. However, as soon as you slow down enough to catch up on your oxygen debt, the lactic acid is immediately turned into more energy to power your muscles. In fact, lactic acid is a much better fuel for muscles than sugar, the second best source of energy. It is converted to energy with the lowest need for oxygen.

The major effect of regular training is to teach your muscles to use the lactic acid for energy before it accumulates in sufficient quantities to make muscles acidic to cause the painful burn and loss of strength and speed. You turn lactic acid into energy only in the mitochondria, small chambers inside muscle fibers. The more intensely you train, the greater your oxygen debt, so the larger your mitochondria become and the more mitochondria you produce in muscle cells. This helps you to turn lactic acid into energy for your muscles and requires the least amount of oxygen. Intense training is the best way to teach muscles to use lactic acid for energy. Using lactic acid efficiently for racing makes you faster and stronger and gives you greater endurance, even in competitions lasting many days.

The best way to grow new mitochondria, and to enlarge the ones that you have, is to do interval training. You move as fast as you can for a short period, become severely short of breath, slow down until you regain your breathing, and then go as fast as you can again. According to Dr. Brooks, "The intense exercise generates big lactate loads, and the body adapts by building up mitochondria to clear lactic acid quickly. If you use lactic acid up, it doesn't accumulate."

More than 20 years ago, Dr. Brooks showed that lactic acid moves out of muscle cells into the blood and enters all your organs including the liver and heart to give them an extraordinary source of energy that requires less oxygen than any other source. So the harder you exercise, the more efficiently your mitochondria turn lactic acid into energy requiring the least amount of oxygen.

In my next post I'll explain the different types of intervals and how to use them in your program, whatever your level of fitness.

Friday, October 22, 2010

Taking Sugar When You Exercise Is Good for You

My last post showed how eating refined carbohydrates and drinking sugared liquids at rest can cause high blood sugar levels, increasing risk for diabetes, heart attacks and premature death. However, during exercise, sugared drinks help you move faster and stronger. It is usually safe to take sugared drinks while you exercise because blood sugar levels rarely rise too high during exercise or for an hour afterward. Contracting muscles draw sugar so rapidly from the bloodstream that there is no sharp rise in blood sugar.

• Contracting muscles help to prevent the high rise in blood sugar that follows eating refined carbohydrates during rest (1).
• Unlike resting muscles, contracting muscles do not require insulin to move sugar inside their cells (2).
• Contracting muscles remove sugar maximally from the bloodstream, without needing insulin, during & up to one hour after exercise. The effect tapers off to zero at about 17 hours (1),(3),(4).

How fast you can run, swim, ski, skate, cycle or move your muscle in any sport depends on the time it takes to move oxygen from your lungs into your muscles. Anything that reduces your oxygen requirements will help you to move faster in sports. Your muscles burn carbohydrates, proteins and fats for energy. However, carbohydrates (specifically the sugar, glucose,) require the least oxygen to power your muscles. Anything that sends sugar rapidly into your bloodstream increases passage of sugar into muscles and helps them to burn a greater percentage of sugar so you can move your muscles faster with greater strength.

Sugared drinks provide sugar to your muscles much faster than sugared solid foods. When food enters your stomach, the pyloric sphincter closes and the stomach can squeeze only the soupy liquid into your intestines. Sugared liquids enter your intestines immediately while some sugared foods can stay up to five hours in your stomach.

Recent data show that glucose-fructose drinks are far more effective than plain water or drinks that contain just glucose in leaving the stomach faster and bringing fluid into the bloodstream faster to improve hydration during intense exercise. (Scandinavian Journal of Medicine & Science in Sports, February 2010). Therefore the best drinks to maintain endurance are those that contain glucose and fructose. Exercise drinks made with high fructose corn syrup (HFCS) may have an advantage over those sweetened with cane or beet sugar.

ALL sugared drinks should be consumed only during exercise or immediately after. When you are not contracting your muscles, quench your thirst with water or no-calorie beverages.

Wednesday, October 13, 2010

Why Sugar Can Shorten or Lengthen Your Life

A high rise in blood sugar can damage every cell in your body. When blood sugar levels rise too high, sugar can stick to the surface of cell membranes. Once stuck there, it can never get off. In a series of chemical reactions, glucose (the only sugar that circulates in your bloodstream) is converted to another sugar called fructose and eventually to a sugar alcohol called sorbitol that destroys the cell to cause every know side effect of diabetes: blindness, deafness, heart attacks, strokes, kidney damage and so forth.

When you eat, sugar can go into:
• your muscles, to make you a better athlete and prolong your life,
• your brain, to keep you smart and alert, or
• your liver to store sugar for future use. Sending too much sugar to your liver can make you fat, increase your risk for a heart attack and shorten your life.

At rest, your brain requires more sugar than the rest of your body combined. Ninety-eight percent of the energy to fuel your brain comes from sugar, so your brain has to have sugar available all the time. A constant supply of blood sugar to your brain helps keep you smart and alert. If your blood sugar level drops too low, you pass out, so your liver always tries to protect you from low blood sugar levels. When blood sugar starts to drop too low, your liver works to save your brain by releasing stored sugar from its cells into your bloodstream. If not enough sugar is available, the liver converts protein into sugar to keep your brain supplied.

Resting muscles are passive and can draw sugar from the bloodstream only with the help of insulin. Contracting muscles can remove sugar directly from the bloodstream without needing insulin. Contracting muscles are also extraordinarily sensitive to insulin, so it takes far less insulin to supply your muscles with sugar during exercise. These beneficial effects are maximal during exercise and for up to an hour afterward and then taper off to zero about 17 hours after you finish exercising.

When your muscles are inactive, you should avoid sugar and all refined carbohydrates. When your blood sugar rises too high, all the extra sugar goes to your liver, and that's when you damage your health. The high rise in blood sugar causes your pancreas to release huge amounts of insulin. This increases risk for a heart attack because insulin constricts arteries leading to your heart to block blood flow there. Insulin converts sugar to triglycerides and your blood fills with this fat (high triglycerides). High triglycerides increase risk for clotting, so your body tries to protect you by using the good HDL cholesterol to carry triglycerides from your bloodstream to your liver (low good HDL cholesterol). The increase in triglycerides can cause liver damage (fatty liver). Insulin also causes the extra fat to be deposited into fat cells in your belly (fat belly). Full belly fat cells block insulin receptors to make the blood sugar and insulin levels rise even higher.

People who have small buttocks are most likely to deposit fat in their bellies and are at the highest risk for diabetes and heart attacks. If you have a fat belly and small hips, you already have insulin levels that are high enough to cause severe damage to your health and are at high risk for diabetes and heart attacks. The combination of high blood insulin, triglycerides and sugar, low good HDL cholesterol and deposition of fat in the belly is called Metabolic Syndrome which means you are at high risk for diabetes and heart attacks. It happened because you eat too much sugar and refined carbohydrates when you are not exercising.

On the other hand, taking sugar when you exercise is good for you. I'll explain why in the next blog post.

Saturday, October 09, 2010

Strength Training to Improve Endurance

Weight lifting can improve performance in endurance sports such as running, cycling or rowing. A study from Spain divided highly trained, competitive rowers into four groups:

1) four arm exercises leading to repetition failure,
2) four exercises not leading to failure,
3) two exercises not to failure, and
4) no resistance training.

All four groups did the same endurance training (Medicine and Science in Sports and Exercise, June 2010). Those who did the four exercises not to failure improved the most in *rowing performance, *lifting the heaviest weight that they could lift once, and *the highest muscle power output.

Athletes who train primarily for strength must train to muscle failure. That means that they lift weights repeatedly until they can barely lift that weight another time. This causes muscle damage that is necessary for maximum muscle growth and strength. The next-day muscles soreness tells them that their muscles are damaged and when thy heal, their muscles will be stronger. Then they take easier workouts until the soreness goes away and repeat their muscle-damaging workouts.

However, athletes in endurance sports must take long hard workouts lasting many hours. If lifting weights causes so much muscle damage that they cannot do their endurance workouts, they cannot compete in their sports. This study shows that athletes in endurance sports can benefit from lifting weights, but they should not go to failure so often that it reduces their workouts that are specific for their sports.

Tuesday, October 05, 2010

Lifestyle More Important than Genes for Longevity

How long you live is usually up to you. Extensive research show that most people who live to be 100 have never had any one else in their family also live to be 100. Longevity researcher James W. Vaupel of the Max Planck Institute in Germany feels that longevity is only three percent genetic and 97 percent environmental. Compare that to factors that govern how tall you will be, which are more than 80 percent genetic.

For most people, living to 90 or 100 requires a healthful diet, daily exercise and avoidance of exposure to life-shortening infections and toxins. Centenarians virtually never have diabetes or arteriosclerosis, the most common causes of death in North America today.

One of the best ways to compare the effects of genetics and environment on lifespan is to study twins (Twin Research, December 1998). The Danish Twin Study showed that a woman whose twin sister lives to be 100 has a four percent chance of living that long (the general population has about a one-percent chance). The Swedish Twin Registry Study followed 3,656 identical and 6,849 same-sex fraternal twins. By analyzing the age of death of twins born between 1886 and 1900, the authors found that longevity is determined a maximum of one-third by genetics and more than two-thirds by environmental factors.

Certain genes have been found to shorten or extend life, but reports on these genetic variations show that they are rare and exceptional. Paul Lichtenstein of the Karolinska Institute reported a gene called APO E4 that shortens life by carrying cholesterol into arteries to form plaques, increasing heart attacks and dementia. There is also a long-life gene called CETP-VV that prevents heart attacks and dementia. People who have CETP-VV have high blood levels of the good HDL cholesterol and large particle size cholesterol that prevent heart attacks.

However, most of the diseases that shorten life are caused primarily by environmental factors. The greatest killers in North America (heart disease, cancer, diabetes, dementia) share the same primary risk factors:
• being overweight,
• not exercising,
• not eating enough fruits and vegetables,
• eating processed meats and red meat,
• smoking,
• drinking alcohol to excess,
• storing fat primarily in your belly, and
• lack of vitamin D.

The more risk factors you have, the greater your chance of suffering debilitating disease and dying prematurely.

Monday, October 04, 2010

Emergency Resuscitation

You are in a room where a person suddenly drops to the floor unconscious. You put your ear over his heart and hear no heartbeats. That person is dead unless you pump on his chest immediately to circulate blood to bring enough oxygen to keep his brain alive, and then shock his heart with an electrical defibrillator to make it start beating again.

He passed out because •his brain suffered from lack of oxygen, •caused by lack of blood circulating to his brain, •caused by his heart fibrillating (shaking rather than pumping) or having a heart beat too weak to pump blood. His brain will die in a minute or two if you don't circulate blood by compressing his chest, and his heart will not start beating again unless you shock it as soon as possible, within about ten minutes.

Recent studies show that:

Compressing the chest first is just as successful as using the electrical defibrillator first (BMC Journal, September 2010). A study of 1,503 patients showed that survival rates were the same for immediate defribrillation and after at least 90 seconds of chest compressions before electrical defibrillation.

• Interrupting chest compressions during resuscitation reduces the chances of heartbeat return to normal after electrical shocking (defibrillation). For every second of a pause in compressions there is a one percent reduction in the likelihood of success (BMC Medicine, February 6, 2009; Circulation, October 2009).

• Mouth-to-mouth resuscitation is no better than just pressing on the chest (NEJM, July 29, 2010). You may not need to do mouth-to-mouth resuscitation in adults. However, this may not apply to children because of their small lungs.

• Place the heel of one hand between the nipples and the other hand on top of that.

• Keep elbows straight with your shoulders directly over your hands.

• With your upper body weight, push down on the chest two inches deep at 100 compressions a minute.

• Continue until signs of movement or until emergency help arrives.

Friday, October 01, 2010

Prolong Life with Exercise

How does exercise prolong life? The leading theory is that exercise prolongs life and prevents heart attacks and cancers by causing the body to dispose of free radicals with increased production of antioxidants.

Exercise speeds up the reactions that turn food into energy, so exercise actually increases the production of free radicals. The body responds to this increased production of free radicals during exercise by producing tremendous amounts of antioxidants that sop up the free radicals and render them harmless.

Most cells in your body have mitochondria, very small energy-producing chambers that number anywhere from a few to thousands in each cell. As you age, mitochondria in muscles decrease in number and size. This interferes with your body's ability to burn sugar efficiently for energy, so they produce more free radicals. Anything that increases the number and size of mitochondria helps to protect you from free radicals. Exercising helps to prevent loss of mitochondria and even makes them larger (Exercise and Sport Sciences Reviews, April, 2007).

• Mitochondria convert molecules from the sugar in food that you eat to other molecules to release energy to power most cells in your body.
• They do this by shuffling electrons from one molecule to another.
• As electrons are shuffled to produce energy, extra electrons accumulate inside mitochondria.
• Free electrons must attach immediately to something.
• They can attach to hydrogen atoms to form water and become harmless, or
• They can attach to oxygen atoms to form free radicals that can damage cells.
• Free radicals attach to your DNA genetic material in cells to damage them which causes cells to act differently than they are supposed to.
• The genetic material in cells tells the cell what to do.
• If your genetic material is functioning properly, it directs the cell to divide a certain number of times and then die, called apoptosis.
• If you genetic material in cells is damaged, the cells can become defective and go on to live forever to become cancers. • Cells with damaged genetic material also can cause heart attacks and other life-shortening conditions.

Furthermore, a team from Yale University showed that as you age, you lose your ability to make the enzyme AMP-activated protein kinase (AMPK). This enzyme functions to increase mitochondria in muscles (Cell Metabolism, February 2007). Anything that reduces the number or efficiency of mitochondria interferes with your body's ability to burn sugar for energy. As a result, blood sugar, fat and cholesterol levels rise. The extra calories that are not burned accumulate in your body as fat in your muscles, liver and fat cells. This causes you to gain weight. Extra fat in cells block their ability to take in sugar from the blood stream, so blood sugar levels rise and you are at increased risk for developing diabetes. Extra fat in the liver prevent the liver from removing extra insulin, so insulin levels rise to constrict arteries and cause heart attacks. Insulin also makes you hungry all the time to increase your chances of gaining weight.

AMPK is increased by exercise and by some of the drugs used to treat diabetes, such as metformin. The best way to increase the number and size of mitochondria in your cells is to exercise. If you do not have a regular exercise program, you are shortening your life.