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Caffeine Improves Endurance

All athletes eventually learn that caffeine helps them to exercise faster and with more force over longer periods of time (J Strength Cond Res, 2009 Jan;23(1):315-24). In January 2004, caffeine was removed from the World Anti-Doping Agency Prohibited List primarily because it was impossible to ban because it is in coffee, tea, chocolate, soft drinks and just about every sports drink or supplement advertised to improve athletic performance.

How Caffeine Increases Endurance

Caffeine increases endurance during long events such as a marathon, triathalon or bicycle race by helping muscles use more sugar. Caffeine increases the entry of sugar into muscles by as much as 26 percent (Journal of Applied Physiology, June 2006).

The limiting factor in how fast an athlete can move is the time it takes oxygen to get into the exercising muscles. Muscles use sugar, fat and, to a lesser extent, protein for energy. Since sugar requires less oxygen than protein and fat do, anything that increases muscles' use of sugar will also help to make that person faster in events that require endurance. Therefore athletes have to take sugar along with the caffeine to enhance performance.

Caffeine also helps athletes run faster in both short and long-distance races. In short races, it makes athletes faster by causing the brain to send messages along nerves to cause a greater percentage of muscle fibers to contract at the same time.

Caffeine Is Not a Diuretic During Exercise

Caffeine can increase urination in people who take it when they are not exercising. However, this rarely happens during exercise. Caffeine-containing drinks contain a significant amount of fluid that helps to keep athletes hydrated during exercise.

Can You Be Harmed by Taking Caffeine?

Nobody really knows how much caffeine you can take in without harming yourself. Caffeine is a potent stimulant that can cause irregular heartbeats in people who already have heart disease, and raise blood pressure in people with hypertension. Most research shows that it doesn't take more than two to four cups of caffeinated soft drinks to increase endurance.

How Much Is Effective?

A caffeine dose of 3 mg/kg body weight improves cycling performance in well-trained athletes. That comes to a little more than 300 mg prior to or during a competition. Doubling the dose to 6 mg/kg(-1) body mass does not give any additional improvement in performance (J Sports Sci, 2012;30(2):115-20). Caffeine is effective when taken before and/or during competitions (J Strength Cond Res, 2009 Jan;23(1):315-24). Caffeine continues to improve performance when taken during several days of competition (Nutr Res, 2012 Feb;32(2):78-84). This study showed that heart rate during exercise was significantly higher with caffeine versus placebo.

Should You Avoid Caffeine Before Competitions?

Caffeine is thought to lose its performance enhancing beneficial effects with repeated exposure, so athletes who want to gain maximum advantage from caffeine during competition are often told to avoid drinking caffeinated beverages for several days prior to major competitions.

However, in a double-blind placebo-controlled cross-over design study, involving four experimental trials, bicycle racers who used caffeine regularly were asked to stop all sources of caffeine (coffee, tea, chocolate, etc) for four days prior to time trials. They then raced time trials after taking caffeine or being fed placebos. Their improved times with caffeine were similar whether they had abstained from caffeine for four days or they had not (J Sports Sci, 2011 Mar;29(5):509-15).


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Pick Fast Runners by the Way They Walk

Many football coaches can pick their halfbacks just by watching them walk. The fastest runners are often flat footed, pigeon toed, and bow legged.

Flat Feet: When you run, you land on the outside bottom part of your foot and roll toward the inside. This is called pronation and is good because it helps to protect the bones of your feet from breaking from the tremendous force of your feet hitting the ground during running. When you run at 6-minute mile pace, the force of your foot striking the ground equals three times your body weight.

Most people who have what appears to be flat feet really have normal arches. Their arches are normal, but appear to be flat because they roll inward excessively when they walk or run. Excessive rolling inward feet force your arch to touch the ground. This excessive rolling inward during running makes you faster because excessive rolling in causes your feet to hit the ground with greater force to drive you forward faster.

Pigeon Toes: Those who walk with their feet pointed inward (pigeon toes) usually have very strong muscles in the back of the lower legs. These very strong muscles in the inside back of the lower legs pull the front part of the foot inward. When you run, the same muscles raise you up on your toes to drive you forward with greater force.

Bow Legs: Having bowed legs means that your knees are further apart than your ankles when you walk or run. That means that they have a greater distance to whip inward as you step off from one foot to the other. This drives you forward with greater force to help you run faster.


Lifestyle Changes to Treat Impotence

An article in European Heart Journal showed that inability to achieve or sustain an erection in middle-aged men often precedes a heart attack by about three years (European Heart Journal, published online April 24, 2013). Another review of six clinical studies in four countries showed that avoiding lifestyle factors that cause heart attacks helps men to regain their ability to achieve and maintain erections. (JAMA Internal Medicine, November 15, 2011).

The Same Factors That Cause Impotence also Cause Heart Attacks

Impotence and heart attacks share many of the same risk factors as the most common cause of both is damage to the inner lining of arteries (Rev Med Brux, 2007 Sep;28(4):360-6). Most men who become impotent as they age suffer from arteriosclerosis, and have high blood sugar and cholesterol and high blood pressure, and are at increased risk for diabetes and heart attacks (J. Sex Med, 2005 Jan;2(1):40-52).

If You Cannot Sustain an Erection

Check with your doctor and get the usual tests for the hormones testosterone and prolactin. Chances are high that your hormone levels are normal and that sloppy lifestyle habits are the cause of your impotence now and a heart attack in the future. If arteriosclerosis is the cause of your impotence, you need to follow every lifestyle change recommended for people who are at increased risk for heart attacks.

Impotence (and high risk for heart attacks) can be caused by:

• any chronic disease, particularly diabetes or metabolic syndrome;

• smoking cigarettes, drinking too much alcohol, abusing any drug, being overweight, not exercising, breathing polluted air;

• poor dietary habits, such as eating too much red meat, fried foods and sugar added foods, drinking sugared liquids (including fruit juices), not eating large amounts of fruits and vegetables;

• emotional diseases such as depression;

• various medications (list)


This week's medical history:
Chris Klug, the Bravest Olympian

For a complete list of my medical history biographies go to Histories and Mysteries


Recipe of the Week:

Oatmeal Bars

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


July 14th, 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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