the so-caUed aerobic exercises.
Aerobic exercise isexercise mUd enough that your muscles are not deprived of oxygen.
When muscles exercise aerobicaUy, theydon't increase muchin mass and theydon't requireas much glucose for energy.
Anaerobic exercise deprives the muscles of oxygen; it tiresthem quickly and requires nineteentimesas much glu cose to do the same amount of work as aerobic exercise.
When you perform anaerobic exercise, your muscles break down for the first 24 hours, but then they buUd up over the next 24 hours.
I have little old ladies performing weight-Ufting exercise.
They're never going to look like Arnold Schwarzenegger , it's physicaUy impossible because women haven'tthe hormones for it , but they feel much better and are certainly stronger because of it.
Theyalso buUd enough muscleto reduce their insulin resistance.
Butwhatabout aerobic exercise, suchasjogging or outdoor biking?
I don't think it's as valuable for diabetics , or for anyone reaUy, for reasons weshaU discuss.
StiU, I usuaUy suggest that mypatientsengage in activities that they wiU enjoyand wiU continueto pursue in a pro gressive fashion.
Progressive exercise is exercise that intensifies over a period of weeks, months, or years.
Below are Usted various character isticsof an appropriate exercise program: • It should comply with any restrictions imposed by your physi cian. • The cost should not exceed your financial limitations. • It should maintain your interest, so that you'U continue to pur sue it indefinitely. • Thelocation shouldbe convenient, andyoushouldhave the time to work out at least every other day.
DaUy activity is very desir able. • It should be of a progressive nature. • It should ideaUy buUd muscle mass, strength, and endurance. • The same muscle groups should not be exercised anaerobicaUy two days in a row.
AEROBIC AND ANAEROBIC EXERCISE
You've often heard of aerobics, and now you've seen me mention "anaerobic" several times. What makes one of these types of exercise better for diabetics than the other?
224 Treatment
Our muscles consistoflong fibers that shorten, or contract,when they perform work likeUfting aloador moving the body.AU muscle fibers re quirehigh-energy compoundsderived from glucose or fatty acids in or der to contract.
Some muscle fibers utilize a process caUed aerobic metabolism to derive high-energy compounds from smaU amounts of glucose and large amounts of oxygen.
These fibers can move Ught loads for prolonged periods of time, and are most effective for "aerobic" pur suits, such as jogging, race walking, aerobic dancing, tennis, nonsprint swimming, moderate-speed bicycling, and simUar activities.
Other mus cle fibers canmove heavyloads but only forbrief periods.
They demand energyat a very rapid rate, and so must be able to produce high-energy compounds faster than the heart can pump blood to deUver oxygen.
They achieve this by a process caUed anaerobic metabolism, which re quires large amounts of glucose andvirtuaUy no oxygen.
This is of interestto diabetics fortwo reasons.
First, the blood sugar drop during and after nearly continuous anaerobic exercise wiU be much greater than after a simUar periodof aerobic exercise because of this requirement for large amounts of glucose.
Second, as your body becomes accustomed to this requirement, it wUl adjust to the stresses you put on it and more efficientlytransport glucose into your muscle ceUs.
As muscle strength and bulk develop, glucose transporters in these ceUs wiU increase greatly in number.
Glucose transporters also multiply in tissues other than muscle, including the liver.
As a result, the efficiencyof your own (or injected) insulin in transporting glucose and in suppressing glucose output by the liver becomes considerably greater when anaerobic exercise is incorporated into your program.
In relatively short order, you wiU develop greater insulin sensitivity for lowering blood sugar.
SimUarly, your requirements for insulin (that which you create or inject) wiU diminish.The overaU drop in in sulin in your bloodstream wiU reduce your body's abilityto hold on to stored fat, thus further lowering insulin resistance.
Think here of the Pimas.
Not only did they gain access to an almost unlimited food supply,they also went from a strenuous existence,one that naturaUy incorporated both aerobic and anaerobic activity, to one that was almost entirely sedentary.
Thus their circumstances were changed utterly from what you might caU the biological expectations of their bodies.
Of course, it's not just the Pimas who are sedentary.
When you understandhow to meet yourbody'sevolutionaryexpecta tions, you can begin to bring it back into balance.
Anaerobic metabolism produces metabolic by-products that accu-
Using Exercise to Enhance Insulin Sensitivity 225
mulate in the active muscles, causing pain and transient paralysis , for a few seconds, youjust can'tcontractthat muscle again.
Since these by-products are cleared almost immediatelywhen the muscles relax, the pain likewise vanishes upon relaxation, as does the paralysis.
You can identify anaerobic exercise by the local pain and the accompany ingweakness.
This painisUmited to the muscles being exercised, goes away quickly when the activity stops, and does not refer to agonizing musclecramps or to cardiacpain in the chest.
Anaerobic activities can include weight Ufting, sit-ups, chinning, push-ups, runningup a steep incline, uphitt cycling, gymnastics, using a stair climber, and so forth, provided that these activities are performed with adequate loads and at enough velocity to cause noncardiac pain or transient discomfort (not heart attack, but the pain of "no pain,no gain").
BODYBUILDING: NEARLY CONTINUOUS ANAEROBIC EXERCISE
Continuous anaerobic activity, as you can weU imagine, is reaUy im possible.
The pain in the involved muscles becomes intolerable, and theweakness that develops with extreme exertion leaves youunable to continue.
Nevertheless, youcanapproach thisgoal byusingthe special "inverted pyramid" technique described on page 228.
BodybuUding, or resistance exercise , which includes weight Uft ing,sit-ups, chinning, and push-ups , focuses on one muscle group at a time and then shifts the focus to anothermuscle group.If you use the inverted pyramid technique you can achieve nearly continuous anaerobic activity, but on a rotating basis.
After you finish exercising certain of your abdominal muscles bydoing sit-ups, for instance, you switch to push-ups, which focus on various arm and shoulder mus cles.
From there, yougoto chinning.
SimUarly, different weight-lifting exercises also focus on different muscle groups.
Anaerobic exercise also can increase the benefits of exercise in stimulating heart rate and thereby exercising the heart.
To maintain an elevated heart rate, you switch immediately from one anaerobic exercise to another, without resting in between.* I personaUy preferthis type of activity for type 2 or obesediabetics
*This type of cardiac exercise is not nearly as effective in raising heart rate as those described under"Cardiovascular Exercise," page 230.
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because , as I have said before and wiU say again , the buildup of muscle mass lowers insuUn resistance and thereby facUitates both blood sugar control and weightloss.
A number of my patients engage in bodybuUding exercises, includingmen and women over sixtyyears of age.
Theyare aU verypleased with the results.* Sincethe pubUcation of the firstedition of this book, there has been a change in our societyin the recognition of the importance of this kind of exercise.
Asignificant benefitis its abUity to help increasebone density.
Bones, likemuscles, tend to be only as strong as they need to be.
When you strengthen your muscles, you're also exercising your bones , your muscles, afteraU, are attachedto your bones;when they contract, your bones move on their joints.
If your bones weren't as strong as the muscles attached to them, they'dsnap.
Some Suggestions for a Bodybuilding Routine Please refer back to "Restrictions on Exercise," page 216.
These restric tions and cautions apply especiaUy to bodybuUding.
Even if you have room in your home, and the finances, to equip your own private gym, I usuaUy recommend that people go to an out side gym or health club to learn the different exercises before begin ning an anaerobic exercise program.
Then, if you want to buy dumbbeUs or a weight-lifting machinefor use at home, that's fine.
But it's important to learn good technique and good form first.
You can also consult books on the subject,but at least a fewsessions supervised by an experiencedinstructor is best.
Equipment. Foryour upperbody, you're goingto haveto useweights. I don't recommend that you Uft barbells, they can be dangerous, and you therefore must have assistance if you're using them , but I do recommend dumbbeUs and weight-Ufting machines, which for the most part are quite safe to use.* Whether you're using dumbbeUs at
A number of years ago, a report from the human physiology lab at Tufts Uni versity reported that onlytwelve weeks of weight trainingtripledthe strength of male subjects ages 60-96.Thiswas believed to improve their qualityof life sig nificandy.
Subsequent studiesshowed similareffects in women. f A number of inexpensive multiexercise machinesare on the market that utilize thick rubber bands instead of weights.
Beware of these: since you have to stop and change the bands to change resistance, they do not permit true anaerobic training.
Hydraulic and pneumaticmachines that utilize rotary knobs to adjust settings are usuallyexcellent but often quite cosdy.
Using Exercise to Enhance Insulin Sensitivity 227
home or in the gym, they should be soUd cast iron, usuaUy painted black enamel or gray. They're inexpensive , usuaUy 50-75 cents a pound, so a 10-pound dumbbeU costs about $5-$7.50. Don't use dumbbeUs consisting of a bar with plates on either end that can be added or removed. These can be dangerous , the plates frequently sUde off, and they also defeatthe wholemethod that I advocate (see "Technique," below).
Exercises.
Ifyou're going to a health club or gym to learn the ropes, I suggest that you learn fifteen upper body exercises, and as many lower body exercises as are avaUable.
Upper body would be for the arms, hands, shoulders, flanks, chest, abdomen, andback.
Ifyou're go ing to the gym every day, which I recommend, you'd do your upper body exercises on one day, andlower body exercises the next.
Why al ternate days?
Becauseof the muscle breakdown over the first 24 hours after exercise and the need for time to rebuUd.
So on the second day, whUe you're doing your lower body exercises, your upper body mus cles are rebuUding.
As you can guess, there are more muscle groups that work in more ways in the upper body than in the lowerbody, so there are fewer sen sible lower body exercises.
If you're using a treadmiU, a stair, a bike, anda cross-country ski machine aU in thesame day, you're exercising more or less the same lower body muscles witheach apparatus, which isn't sensible.
The other types of lower body exercises that involve weight lifting are few in number: leg presses, knee curls, toe presses, and knee extensions.
Some gyms have machines to exercise yourlegs asyou spreadthem apart or squeeze them together, but in aU, there are at most six leg exercises commonly avaUable.
As a consequence, I always add some other exercises on the days I do lower bodyexercises: grip strengthening, side bends (which exer cise the sidemuscles), and sit-ups or crunches, asweU as what's caUed cardiovascular exercise (page 230).
Theinstructor at yourhealth club wiU be able to help you with aU of these.