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Benefits of High-Intensity Interval Training

To be competitive, all athletes must train very intensely some of the time. New research from McMaster University in Canada shows that short term, high-intensity interval training on a bike can also provide you with all the health and fitness benefits of exercising less intensely for a much longer period of time (The Journal of Physiology, March 2010). Subjects used a standard stationary bicycle and performed a workout of ten 1-minute sprints with a 1-minute rest between each at 95 percent of their maximal heart rate, three times a week. This takes less effort than an all-out sprint at close to 100 percent of maximal heart rate. The study supports other research that shows that high-intensity training improves speed and endurance far more than long slow distance and is necessary for training for athletic competition.

The same authors showed that a similar short workout of all-out sprinting at maximal heart rate took about 90 minutes per week (three workouts of 30 minutes each) and was as effective in achieving fitness and health benefits as many hours of exercising at a much more leisurely pace (The Journal of Physiology, September 2006). High intensity, short-interval training improves fuel and oxygen delivery to muscles, helps the removal of waste products, and increases the number and efficiency of mitochondria that help muscles use oxygen to burn food for energy. These changes have been shown to reduce risk for heart attacks, strokes, diabetes, weight gain and even some cancers.

The authors make no mention of alternating intense stress and low-intensity recovery workouts, in which you spend more than 80 percent of your exercise time going at a very low intensity. Training intensely without recovery workouts markedly increases your chances of injuring yourself.

High-intensity training can cause heart attacks in people with blocked arteries and muscle injuries in anyone. Before starting, a) check with your doctor to make sure your coronary arteries are open and b) you should be able to pedal on a stationary bicycle slowly for at least an hour a day for several weeks. A program of high-intensity intervals:

• will improve speed and endurance much more than slow long- distance workouts

• should not be done when muscles feel sore or you feel sick because it increases your chances of injuring yourself

• should be part of a "stress and recover" program in which you go intensely never more often than three times a week and spend far more time exercising less intensely.

High-intensity interval training causes muscle burning and severe shortness of breath, so don't do it unless you enjoy the thrill of competition.

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Dear Dr. Mirkin: Will arginine supplements make me faster?

It pays to be skeptical. An article from the University of California at Los Angeles showed that cyclists over age 50 who took a commercially available supplement containing the amino acid, arginine, and antioxidants gained a 16.7 percent increase in their anaerobic threshold at three weeks (Journal of the International Society of Sports Nutrition, March 23, 2010).

Muscles need oxygen to convert food to energy. Anaerobic threshold occurs when lactic acid starts to accumulate in the muscles, meaning that a person cannot bring in enough oxygen to cover the amount of fuel muscles use for energy, so the person becomes severely short of breath and has to slow down. Arginine is an amino acid protein building block that can stimulate the blood vessels to increase production of nitric oxide. This dilates blood vessels which can increase blood flow to muscles. The authors demonstrated that arginine did not increase the maximal amount of oxygen that a person can take in and use (VO2max).

1) The only people who can benefit from increased anaerobic threshold are those who are exercising as hard as they can. It does not benefit people who are exercising at less than their maximal capacity. If you take these supplements and do not exercise at your maximum, you are wasting your money. Several studies show that nitric oxide releasers may help athletes exercise longer, but the data are weak, sparse and not very impressive. If you are already exercising as hard and as fast as you can, taking these supplements may let you do more work, which may make your muscles stronger (Medicine & Science in Sports & Exercise, December 2000).

2) Promoters of these supplements recommend doses of 6,000-10,000 mg per day and most athletes who use them take far more than that. Each pill used in this study contained 5200 mg. Side effects include nausea, stomach cramps, diarrhea, gout and a worsening of asthma. High doses may drop blood pressure which could harm performance. During exercise you need higher blood pressures to enhance ciruclation to muscles. A person with resting blood pressure of 120/80 can expect it to rise to 200/80 while jogging.

3) The study subjects took arginine at bedtime. We do not know if arginine taken at night would have any effect whatever on nitric oxide production the next day. Exercise, by itself, raises blood levels of nitric oxide (American Journal of Hypertension, August 2007). So if you want your arteries to make more nitric oxide, go out and exercise.

4) Arginine is so readily available from food that deficiencies of arginine are virtually never reported. Your body can make it and it is abundant in meat, poultry, seafood, diary products, all grains, nuts, legumes and other seeds, and in chocolate.

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Dear Dr. Mirkin: Do any foods or diets help to prolong the lives of cancer patients?

We don't know, but a study from the University of Illinois at Chicago shows that higher survival rates from ovarian cancer were found in those who ate a diet rich in fruits, vegetables and whole grains, with the longest survival in those who ate cruciferous vegetables such as broccoli, and yellow vegetables (The Journal of the American Dietetic Association, March 2010). Reduced survival was found in those who ate red meat, milk or other diary products. Eating chicken or fish had no effect on survival. This correlates with data from other studies that show that red meat is associated with increased risk for at least 17 different cancers, while eating fruits and vegetables is associated with decreased risk.

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Recipe of the Week:

Shrimp Curry Salad

You'll find lots of recipes and helpful tips in The Good Food Book - it's FREE

June 21st, 2013
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About the Author: Gabe Mirkin, MD

Sports medicine doctor, fitness guru and long-time radio host Gabe Mirkin, M.D., brings you news and tips for your healthful lifestyle. A practicing physician for more than 50 years and a radio talk show host for 25 years, Dr. Mirkin is a graduate of Harvard University and Baylor University College of Medicine. He is board-certified in four specialties: Sports Medicine, Allergy and Immunology, Pediatrics and Pediatric Immunology. The Dr. Mirkin Show, his call-in show on fitness and health, was syndicated in more than 120 cities. Read More
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