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Benefits of Exercise from a Pill?

Don't believe that you can gain the benefits of exercise without exercising. Many products are promoted to give people bigger muscles and make them better athletes, as well as to help them lose weight and prevent diabetes and heart attacks. They are sold to unsuspecting consumers without needing prescriptions. These products are not approved by the Food and Drug Administration and are likely to be ineffective or even harmful.

This month, a new study used a widely-available supplement called GW501516 on mice to keep their blood sugar levels high so they were able to exercise far longer, faster and with more power (Cell Metabolism, May 2, 2017;25(5):1176–1185). Fatigue during endurance exercise is caused by a drop in blood sugar and anything that keeps blood sugar levels high can help animals exercise longer, faster and with more power. Several previous studies showed that GW-501516 prevents obesity in mice and might help to prevent diabetes and heart attacks.

The Study
We know that anything that keeps blood sugar levels high during prolonged exercise will make you a better athlete by helping you to exercise longer, faster and with more power. Also, anything that burns fat should be able to help you lose excess weight and reduce your chances of getting diabetes and heart attacks. This new study showed that:
• A gene receptor in the bodies of both mice and humans called PPARdelta (PPARD) preserves body sugar by reducing the use of sugar by burning a much greater percentage of fat.
• Exercise activates PPARD.
• Genetically knocking out PPARD in the muscles of mice prevents them from gaining any benefit from exercise training as it prevents them from maintaining blood sugar levels during exercise and therefore they are unable to use exercise to increase endurance.
• A drug called GW501516 activates PPARD.
• Mice normally become exhausted after running 90-120 minutes because that is when their blood sugar usually drops to very low levels. Giving GW501516 to the mice increased PPARD and preserved body sugar so that they could maintain blood sugar levels for more than three hours and therefore keep on running at a fast pace for that long.
• GW501516 prevented the mice from gaining excess weight no matter how much they ate, and therefore raising body levels of PPARD could both prevent and treat obesity and diabetes in mice. The authors of these studies speculate that if a safe version of GW501516 could be found, humans might be able to gain the same increase in endurance and the same weight control benefits just by taking a pill and not having to exercise at all.

A Warning to Everyone
Wow! This sounds exciting -- but wait. The drug that was used to make mice better athletes in this study has been around since the early 1990s, developed and tested by Ligand Pharmaceuticals and GlaxoSmithKline for the possible prevention and treatment of diabetes and heart attacks in humans. They stopped their testing in 2007 when the mice began developing cancers at an alarming rate.

However, despite this danger, high doses of GW501516 had dramatically improved strength, speed and endurance in the mice, so variations of the drug soon became available in health food stores as performance enhancers for athletes and body builders under names such as Cardarine, GW-501516, GW1516, GSK-516 and Endurobol. These supplements are promoted to provide:
• the benefits of exercise without needing to exercise
• a cure for obesity and diabetes
• a way to provide the health and physical benefits of exercise to people who could not exercise for any reason
• a way for body builders to grow larger muscles
• a way for competitive athletes to improve in their sports (by cheating)

Why Would GW501516 Cause Cancer?
The same mechanism that allows GW501516 to increase endurance probably explains why the test animals had such extremely high rates of cancer. In 1922, Otto Warburg showed that most cancers use sugar as their main source of energy, and over the last 100 years, researchers have tried to cure cancer by depriving cancer cells of their sugar supply. GW501516 and its look-alike drugs act in the opposite way by maintaining an over-abundance of sugar in muscles and throughout the body, which could promote the establishment and growth of cancers.

A summary of studies associating GW501516-like drugs with colon, lung and breast cancers was published in Cancer Metastasis Reviews (December, 2011;30(3-4):619–640). An earlier summary can be found in PPAR Research, June 18, 2008. The strong evidence that this drug can cause cancer forced the World Anti-Doping Agency (WADA) to develop a test for GW501516 and related chemicals and in 2009, WADA prohibited athletes from using these dangerous performance-enhancing drugs. Many sports governing bodies and the Olympics have banned GW501516 and test for it in competing athletes.

Mechanism for Improving Sports Performance
The new study showed that GW501516 increased PPARD in mice, preserving body sugar so that they could maintain blood sugar levels far longer. Muscles are powered primarily by converting sugar and fat into energy. Your brain gets almost all of its energy from sugar circulating in your blood. You have enough fat in your body to supply you with energy for several days, but you have only about 2,000 calories worth of stored sugar called glycogen in your muscles and liver. To help keep up your sugar supply, your liver can make new sugar primarily from protein, but that is a slow process, and you start to run out of your stored sugar supply in muscles and liver after about 70 minutes of intense exercise. When you start to run out of sugar, your muscles get more of their energy from fat and can keep going at a reduced pace, but your brain gets 98 percent of its energy from sugar in your bloodstream, so a drop of blood sugar interferes with brain function so it makes you slow down and causes loss of concentration, weakness, and can even make you pass out.

Fatigue in Endurance Sports
Many studies explain the causes and prevention of fatigue during endurance sports. Most marathon runners "hit the wall" at about 18 to 20 miles of a 26-mile race when they suddenly feel exhausted and have to slow down. Bicycle racers can "bonk" after several hours of racing when they suddenly lose their concentration, pass out and fall off their bikes. Scientists used to think that "hitting the wall" was caused by running out of muscle sugar and "bonking" was caused by running out of blood sugar, but these recent studies show that both "bonking" and "hitting the wall" are caused by the same drop in blood sugar, and that all athletes in competitive sports lasting longer than an hour can improve their performances by taking a sugar source during competition. Sugar sources include sugared drinks, sugar-added foods, and fruits and their juices.

How Athletes Use this Information to Cheat Legally Today
Anything that maintains blood sugar levels during exercise helps athletes to move faster, stronger and longer. Cortisone-type drugs can substantially improve athletic performance by raising blood sugar levels to prevent fatigue and prolong endurance. Athletes are prohibited from taking cortisone-type drugs in the Olympics and other competitions because cortisone-type drugs have terrible side effects. Long-term use can cause bone loss, decreased immunity, cataracts, stomach ulcers, insomnia, mood swings, personality changes, depression and more. However, athletes are allowed to take cortisone-type drugs if a doctor prescribes them to treat a medical condition. That means that, for example, an athlete can get a doctor's note for cortisone-type drugs to treat tendon pain (tendinitis) and then win a race "legally" even if testing shows high blood levels of the drugs.

My Recommendations
• Exercise is more effective in prolonging lives and preventing diseases than any drug on the market today. If you do not exercise, you are shortening your life.
• Exercise prevents diseases and prolongs lives through weight control, blood sugar and insulin control, skeletal and heart muscle strengthening, blood pressure control and many other benefits.
• You can prolong your endurance significantly by taking sugar in fruit and other sources during events lasting longer than 70 minutes of intense exercise..
• Eating foods or drinks with added sugars when you are not exercising can raise blood sugar to levels that can damage cells throughout your body to increases risk for obesity, diabetes and heart attacks.
• Perhaps in the future, but certainly not today, doctors may be able to prescribe a safe exercise-simulating and fat-burning drug to people who are unable to exercise because of disabilities or who are obese, diabetic or have other medical conditions that would be helped by rapid weight loss.

May 20th, 2017
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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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