Dr. Mirkin's E-Zine
October 20, 2002
What's the Best Exercise Drink?
The best exercise drink is the one that tastes best to you.
The main cause of fatigue during exercise lasting more than an
hour is dehydration, so the more you drink when you exercise,
particularly in hot weather, the longer you can exercise. You
can't wait for thirst to signal that you are losing fluid. Thirst
is a late sign of dehydration. You won't feel thirsty during
exercise until you have lost between two and four pints, or two
to four pounds.
Researchers in Australia showed that liking a drink is
more important than how much salt or how much sugar is in a
drink. It doesn't make any difference whether a drink is
carbonated or not, or hot or cold (International Journal of Sport
Nutrition and Exercise Metabolism, Volume 12, Issue 1, 2002).
Many sports drinks are advertised to contain the right
concentration of minerals and sugar for exercise. However, Dr.
Carl Gisolphi of University of Iowa showed that fluids are
absorbed from the intestines at a rate that is not affected by the
concentration of minerals or sugar in the drink (Medicine and
Science in Sports and Exercise, June 2001). The only mineral
you need to replace during exercise is salt.
So the best exercise drink for you is the one that you like,
because that's what you will drink the most. Sports drinks are no
better than water and salted peanuts, or cola and pretzels. Any
drink plus any food that contains salt is just as effective as any
sports drink to maintain endurance and prevent heat exhaustion.
Dr. Mirkin's E-Zine
October 27, 2002
Small Muscles Increase the Risk of Stress Fractures
Forty-five percent of competitive female runners develop
stress fractures, small cracks on the surface of the bones in their
legs or feet. Having small calf muscles is the most common risk
factor. When you run, your feet hit the ground with a force equal
to or greater than three times body weight, which can shatter
bones. The largest bones are usually the strongest, and people
with the largest bones have the largest muscles. Runners with
the smallest circumference around their calf muscles are the
ones most likely to suffer stress fractures.
Stress fractures usually start out as a minor discomfort in
the foot, lower leg or pelvis that occurs near the end of a long
run. Usually the pain goes away as soon as you stop running.
On the next day, it hurts in the same spot earlier in the run.
If it hurts to touch a spot on a bone and does not hurt an inch
away, you probably have a stress fracture. X-rays are usually not
sensitive enough to diagnose stress fractures. If your doctor
wants to prove the fracture, he will order a bone scan. Other risk
factors for stress fractures include extreme food restriction and
having irregular periods.
Most of the time, you don't need a cast, but you should
stop running for the three to six weeks it takes for you to be able
to run without pain. If you want to exercise, ride a bike or swim.
People with stress fractures that do not heal may need to take
bone-strengthening medication such as Fosamax.
Dear Dr. Mirkin: How does cranberry juice help to prevent urinary
Women have known for years that drinking cranberry juice
helps to prevent and treat urinary tract infections. Doctors used
to think that the benefit came from the acid in cranberry juice that
made your urine acidic. This was disproved, and it is now known that
there is a specific chemical in the cranberry that prevents bacteria
from adhering to the cells lining the bladder.
A study in the Journal of the American Medical Association
(June 19, 2002) describes results of culturing antibiotic resistant
E. coli that are the most common causes of urinary tract infections .
Urine was collected from women with chronic urinary tract infections
after they drank 240 ml (about 12 ounces) of cranberry juice cocktail.
Almost 80 percent of the bacterial strains were prevented from
adhering to the cells lining the urinary bladder. It did not matter
whether the bacteria were resistant or sensitive to antibiotics.
The authors suggest that proanthocyanidins, tannins that are the red
pigment in cranberry juice, are the component that prevents bacteria
from sticking to bladder cell walls.
Dr. Mirkin's E-Zine
November 10, 2002
If you watch a major bicycle race on TV, you have to be
impressed by how the riders can eat enough to sustain them
through races that require more than five hours of near maximum
effort. If they do not get enough food during their ride, they can
fall off their bikes, lie on the ground unconscious and start to
shake all over in a in a massive convulsion. This is called
bonking: passing out from low blood sugar.
Your brain gets almost all of its fuel from sugar in your
bloodstream. When your blood sugar level drops, your brain
cannot get enough fuel to function properly, you feel tired and
confused and can pass out. There is only enough sugar in your
bloodstream to last three minutes. To keep your blood sugar
level from dropping, your liver must constantly release sugar
from its cells into your bloodstream, but there is only enough
sugar in your liver to last 12 hours at rest. During intense
exercise, your muscles draw sugar from your bloodstream at a
rapid rate. Your liver can run out of its stored sugar and your
blood sugar level can drop, and you bonk.
Bonking is common in bicycle races if a rider does not
eat frequently, but is rare in long distance running races. When
you run, your leg muscles are damaged from the constant pounding
on the roads and you must slow down. However, you pedal in a smooth
rotary motion which does not damage your muscles, so you can
continue to pedal at a rapid cadence for many hours.
To prevent your blood sugar from dropping too low during
any intense exercise lasting more than two hours, eat at least
every 30 minutes. It doesn't matter what you eat: a peanut butter
and jelly sandwich, a sugared drink, an orange, salted peanuts or
anything else. Almost all fit people can take small amounts of food
frequently during exercise without developing stomach cramps.
Dr. Mirkin's E-Zine
November 24, 2002
Walking for Fitness
Walking is a very safe sport because it rarely causes
injuries. Running causes injuries frequently because you take
both feet off the ground at the same time and land with a
tremendous force that can tear muscles and shatter bones. On
the other hand, when you walk, you always keep at least one foot
on the ground and land with minimal foot strike force.
If you want to walk to become fit, you have to move fast.
You should exercise vigorously enough to increase your heart
rate at least 20 beats a minute higher than when you rest. That
means you will be breathing harder and probably perspiring.
There are two ways to increase your walking speed. You can
take longer steps or you can move your feet at a faster rate. To
lengthen your stride, swivel your hips so you reach out further
forward with your feet. This will cause you to twist your body
from side to side, which will tend to make you point your toes
inward when your feet touch the ground. When you point in you
lose distance. Try to point your toes forward with each step.
To move your feet at a faster rate, you have to move
your arms faster. Every time you move one leg forward, you pull
the arm on the same side back and the arm on the other side
moves forward. Your legs will only move as fast as you can
move your arms. Bend your elbows so you can move your arms
faster. The fulcrum of your arm-swing is at your shoulder. The
straighter you keep your elbows, the longer it takes your arms to
swing forward and back. Bending your elbows shortens the
swing and helps you speed up your pace.
Chronic Muscle Aches May Be Treatable
Regular exercisers should expect their muscles to feel
sore on the day after they exercise intensely, but if the soreness
doesn't go away, they need a medical evaluation. When you
exercise vigorously, your muscles are injured. Muscle biopsies
taken on the day after intense exercise show bleeding into the
muscle fibers and disruption of the Z-bands that hold muscle
fiber filaments together as they slide by each other. The
soreness you feel should usually disappear within 48 hours, and
even with the most severe workouts, it should disappear within
a week or two.
If the soreness remains after a few weeks, you should
check with your doctor. You may have an infection anywhere in
your body, an autoimmune disease or other treatable condition.
Some doctors call chronic muscle soreness fibromyalgia, chronic
fatigue syndrome or multiple chemical sensitivities. These
diagnoses are really an admission by the physician that he hasn't
the foggiest idea of the cause. There are reports of people
with muscle pain and normal liver tests having hepatitis C, which
can be effectively treated (see report #G125 in the More Health
section of www.drmirkin.com). If you also have urinary tract
symptoms, you may have mycoplasma, which can be cured with
antibiotics (report #G144 in the More Health section). You could
have Lyme disease or a type of arthritis. Don't accept a
diagnosis of chronic fatigue syndrome or fibromyalgia until you
have an evaluation for a hidden infection or other treatable cause.
Tuesday, October 15, 2002
NUTRITION AND CRIME
OCTOBER 15. This study fell through the cracks last June, and it has not been picked up, to any degree, by major media in the US. Researchers from the University of Oxford enrolled 230 young offenders from a prison at Aylesbury.
Half the prisoners were given a placebo, and half a normal supplement containing vitamins, minerals, and essential fatty acids. The supplemented group showed a staggering 40% reduction in violent offenses, whereas the placebo group showed no such reduction.
It’s clear that prison officials and medical honchos in the US are, by and large, disinterested in results like this. After all, the prison industry DEPENDS on criminals and more criminals, rather than healing these people.
September 12, 2002
A recent study published in the Journal of the American Medical Association showed no measurable benefit to the use of the dietary supplement, Gingko biloba to improve mental function.