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New Evidence on Weight Training and Blood Pressure
Q. Iím a recovering kidney patient who had surgery two years ago. Iíve always been dedicated to an exercise program which includes weight lifting. Since my surgery I have regained my body weight and stamina to their normal levels. Iím 5 ft. 11 inches, 182 pounds, my ideal weight.
During my periodical medical check ups my doctors continue to warn me about weight lifting, since in their view it can cause high blood pressure. I have never read anything about weight training causing high blood pressure. Whatís your view on the subject?
A. Youíre query comes at an opportune time. Arnold Jensen, M.D., a preventive medicine specialist at the Cooper Clinic in Dallas (and my personal physician), just alerted me that in February the American Heart Association (AHA) issued a new scientific advisory saying that a combination of resistance training and aerobic exercise yields greater cardiovascular benefits than aerobic exercise alone. This is a major development; because, as the warnings from your doctors suggest, strength training has often been discouraged for heart patients.
The new advisory is based in part on recent studies showing that resistance exercise minimizes the elevation in heart rate and blood pressure that normally occurs when people lift or carry heavy objects. That makes sense, of course, because strength gained from weight training makes lifting and carrying things easier and less stressful.
Whatís more, Heart Watch (published by the New England Journal of Medicine) reports that the AHA advisory was followed by a review study published in the March issue of Hypertension providing further support for weight training. The researchers compiled data from 11 studies that examined the effect of resistance training on resting blood pressure in previously inactive adults. The subjects in these studies, some of whom were taking medication for high blood pressure, trained with weights 2 to 5 times a week for at least a month. Compared to study participants who did not train, they had a 2 percent reduction in resting systolic (the top number) and a 4 percent reduction in resting diastolic blood pressure (the bottom number). Though small, the reductions in blood pressure were enough to reduce the risk of stroke and heart disease. (Maximum benefits from strength training donít come in four weeks, of course, so it seems likely that training for a longer period would result in greater pressure reductions.)
As I related in The Lean Advantage 3, Dr. Jensen has long maintained that weight training, done properly, helps your blood pressure. He says it develops the small blood vessels, especially those in the often neglected upper body area. In untrained individuals, the veins and arteries are often constricted or closed, which leads to high blood pressure. Jensen, who was largely responsible for introducing weight training at the Cooper Aerobics Center, explains that weight training opens these small blood pathways. The effect is like increasing the diameter of your garden hose: the pressure drops.
Don't Hold Your Breath
The AHA advisory recommends doing a single set of 8 to 15 repetitions, using 8 to 10 different exercises, 2 to 3 times per week. Dr. Jensen adds that itís important to breathe while you lift. Relax between reps and donít hold your breath.
Dr. Jensen practices what he preaches; now 71, heís
weights for over 30 years. Arnie is shown here training
in his well-equipped home gym. (Photo by Jim Stevens)
Weight training is not for everyone, however. According to the advisory, weight training in moderate-to-high-risk heart patients requires more study. It may be too risky for people with uncontrolled high blood pressure, uncontrolled irregular heartbeat, severe valve disease and heart-failure patients who have not been evaluated by a physician for exercise.
I suggest that you talk to your doctors about the new AHA advisory on weight training published in the February 22 Circulation; they can help you reassess the risks and benefits of resistance training in your case. You might also show them the section on weight training and blood pressure in the "Health Factors" chapter of The Lean Advantage 3.
By the way, to the best of my knowledge there is no evidence that weight training causes hypertension.
UPDATE (See main article on weight training and blood pressure above): The Real Age Tip of the Day (www.RealAge.com) recently suggested strength training for people whose blood pressure spikes in response to stress. Stressful situations make just about everyone's BP go up (mine sure does; see article 105), but some people return to normal sooner than others. According to a study reported in the American Journal of Hypertension (Volume 17, Issue 11, November 2004), people with the greatest proportion of lean body mass have better control over fluctuations in blood pressure than those with less muscle mass.
Researchers at the Medical College of Georgia, Augusta, Georgia, measured the body composition of 127 youths and then subjected them to a five-hour stress protocol: two-hour baseline period, one-hour video game competition, and two-hour recovery period. Blood pressure reading were taken every 15 minutes. Lean body mass was found to be the best predictor of change in BP from stress to recovery. The BP of those with the most muscle and the least fat stabilized fastest.
The take home message, according to RealAge: "Keeping your weight down and exercising regularly can help reduce chronically high blood pressure. Your fitness program should incorporate exercises that build strength, stamina, and flexibility." (See article 28 to learn more about RealAge.)
Training on Empty: Good or Bad?
Q. Is training in the morning on an empty stomach more effective for burning fat? Some well-known bodybuilding gurus recommend doing high-intensity aerobics in the morning on an empty stomach to burn fat. Is this supported by scientific fact, or is it bad advice?
A. That sounds logical, I know, but itís bad advice for two basic reasons. The first is simply common sense: You will feel more like training if you eat a small snack beforehand. Itís important to enjoy your training, because youíre not likely to keep doing an activity that you find unpleasant. I usually have a cup of instant coffee, made with one-third water and two-thirds skim milk, and a teaspoon of canola oil (to slow absorption), and a Tigerís Milk energy bar about 30 minutes before my workout. If youíd prefer not to drink coffee and donít like energy bars, a glass of skim milk and an apple would be fine. Avoid concentrated sugars which cause a spike in your blood sugar Ė a candy bar or honey are no-nos Ė or eating so much that you feel full and uncomfortable. Eat something small in volume and easily digested; thatís why I like a Tigerís Milk bar. I eat my main meal as soon as possible after training. Iíll explain why a little later.
The main reason for a pre-workout snack, however, is to supply your brain with the energy it requires to function properly Ė and to avoid cannibalizing your muscles.
All the different tissues of the body, including your muscles, use glucose, blood sugar, for energy. Your brain, however, relies on glucose for energy almost exclusively. If your blood glucose level falls, the brain cannot function properly. The result is usually inability to concentrate, lethargy and confusion, but in extreme circumstances can be blurred vision, shock, and even death. For this reason, the body is programmed to maintain your blood glucose level no matter what the cost. When you understand the mechanism by which this is accomplished, youíll know why you should eat a small snack before you exercise.
Most of the energy for a training session, weights or aerobics, come from the glycogen stored in your muscles. The glycogen comes from what you have eaten over the last several days, not your last meal. It takes a day or two to restore the glycogen to depleted muscles. About 200 grams of glycogen can be stored in your muscles. Muscle glycogen, however, is no help to your brain. As Lawrence E. Lamb, M.D., explained some time ago in The Health Letter, muscle glycogen has to be used by your muscles for energy; it canít get out of the muscles to raise your blood sugar. So where does the glucose for your brain come from?
First, it comes from the glucose contained in your circulating blood. This, however, is only about 20 grams and doesnít last long. Next, it comes from the breakdown of glycogen to glucose in the liver; thatís about 70 grams. The glucose in your circulating blood and that stored in your liver, according to Dr. Lamb, is enough to tide your brain over during the night, but thatís about it. When you get up in the morning the body must look elsewhere to supply glucose to your brain. Unfortunately, if you donít eat, the source of supply is body protein -- not the fat stored on your body.
As you probably know, extra calories from any source, carbohydrate, protein or fat, are stored as fat. "The catch," says Dr. Lamb, "is that this is a one-way street." Fat cannot be used to form glucose. Under normal circumstances, body fat canít supply the needs of the brain. (After about two days of starvation body fat can provide energy to the brain, but thatís clearly not acceptable for our purposes.)
After blood glucose and liver glycogen are used up, the body turns not to fat tissue, but to protein to maintain the blood glucose level. The mechanism is called gluconeogenesis, the manufacture of new glucose. Your liver does the job. It strips the nitrogen from body protein to form glucose. In other words, protein from skeletal muscles and other body structures is used to maintain your blood glucose level.
Dr. Lamb summed it up like this: "In the morning, after an overnight fast, your body has already switched to converting amino acids to glucose. That is one reason why some carbohydrate to support your blood sugar level early in the morning is important. That can help conserve the cell protein, such as found in your muscles."
So, training in the morning on empty, without eating, is a bad idea. The result is exactly the opposite of that desired. Rather than encourage the burning of fat, if forces your body to burn hard-earned muscle.
To the best of my knowledge, Dr. Lambís comments are still state-of-the-art. I have yet to hear any authoritative opinion to the contrary. Until I do, I plan to continue eating a pre-workout snack..
I promised to tell you why I eat a full meal shortly after training. Glycogen replacement is more than twice as great if you eat soon after exercising than if you wait two hours. Itís important to take advantage of that window of opportunity to replenish the glycogen stored in your muscles. Otherwise, the calories consumed may be deposited as fat. As explained on our products page, my favorite post-workout meal is our High Protein Oatmeal. I add mixed vegetables and fruit to the oatmeal and top with skim milk or a multigrain beverage.
Iíve had many questions on this topic. I hope this clears up the confusion about eating a pre-workout snack.
(Youíll find more information on pre- and post-workout meals in The Lean Advantage series, described on our products page.)
Stretching Can Be Hazardous
Q. Iíve been struggling with my level of body fat since I hit 30; Iím now 37. Before that I was as lean as could be. I have my exercise routine pretty much down, but diet is a problem. And to make things worse, two days ago I injured my right leg behind the knee trying Pavelís "wait out the tension" method of stretching. I guess I over did it. I have "zero" flexibility.
Iím waiting a few days to see if the injury clears up. Keeping my fingers crossed that itís just a minor pulled muscle. This means Iím limited to upper body work, and like most females my fat deposits find themselves mainly in my hips/thighs. Any suggestions?
A. In his new book Relax Into Stretch, Pavel recommends rest, ice, compression and elevation (RICE), plus gentle stretching for minor muscle tears. Stop just short of pain, he cautions. According to Pavel, stretching the injured muscle in this manner promotes circulation and healing, and helps maintain the flexibility of the injured area. If you try this, be very careful not to re-injure yourself. If the injury doesnít clear up soon, see your doctor.
You may have stretched the ligaments in the back of your knee. As you probably know, Pavel says stretching the ligaments is unnecessary and dangerous. "Stretch a ligament by only six percent and it will tear," warns Pavel. "A stretched ligament means a loose and unstable joint just waiting for a severe injury," he adds. How can you tell if you are stretching a ligament? "If you feel discomfort or pain in the joint, you are probably doing it," Pavel says. I believe thatís a good rule to remember when stretching: If it hurts donít to do it!
It sounds like you were a little over enthusiastic. When your injury heals and your resume normal training, you should probably lighten up on stretching. Unless youíre into gymnastics, martial arts or some other activity requiring extreme flexibility, thereís no need to go overboard on stretching. As Pavel explains, all you need is a small reserve of flexibility beyond the requirements of your sport and lifestyle. Experts on stretching generally agree that excessive flexibility can be just as bad as not enough, because both increase your risk of injury. Very limber, loose joints tend to be unstable and subject to injury.
Keep in mind that weight training itself, done properly, provides a substantial degree of flexibility. The key is to lift through a full range of motion. Some fitness experts say that strength training shortens and tightens your muscles, making them more susceptible to injury. But I believe thatís a bit of a myth. Iíve been lifting all my life, and tests at the Cooper Clinic show that I am quite flexible, especially in the lower body. Iíve always made a point of lifting through a full range of motion, and while Iíve started stretching in recent years (once a week, after hard aerobics), I believe my flexibility is mainly due to lifting. Lifting has certainly not hindered my flexibility. (See also the account of John Grimekís famous encounter with Dr. Peter V. Karpovich at Springfield College in Massachusetts, page 78 and following in Challenge Yourself.)
The squat is one of the full range
movements that make and keep me flexible.
I maintain a straight back and go all the way down.
Olympic weightlifters are some of the most flexible athletes on earth (see the photo below), and they spend little time stretching. Milo publisher Randall J. Strossen, Ph.D., is probably the most knowledgeable American on the training methods of the Eastern Europeans, who have for many years dominated Olympic lifting; his highly regarded training hall videos are proof of his presence at lifting venues around the world. Randy tells me that the best Olympic lifters rely mainly on the lifts themselves to give and maintain the needed flexibility. They do not emphasize stretching.
As a further indication of this fact, Science and Practice of Strength Training, the highly regarded book by Vladimir M. Zatsiorsky, Ph.D., a world-renowned sport biomechanist and former strength and conditioning consultant for the Soviet Union Olympic teams, contains only one sentence on flexibility exercises. The word stretching does not appear in the index.
This photo, taken by Dr. Strossen, is an example of the marvelous balance and flexibility
of Olympic lifters. It shows Chinese lifter Xugang Zhan jerking 207.5 kilos (458 pounds)
in a deep squat position, to win the 77-kilo (170 pound) class at the 2000 Olympic Games.
(Photo used with permission of Milo magazine. Website: www.ironmind.com/index.asp)
I tell you this not to discourage you from stretching, but to dial down your enthusiasm to a safer level. And Iím not suggesting that you take up Olympic lifting. I simply want to encourage you to lift through a full range of motion; train your whole body, upper and lower, and fully extend and contract your muscles on each repetition. Do that, and the muscle shortening that some say occurs with strength training will be avoided. Your muscles will become strong Ė and flexible. Muscles used through a full range of motion will remain flexible throughout life.
When you stretch Ė and I believe itís a good idea, especially if you have limited flexibility as you claim Ė do it carefully. Never stretch when your muscles are cold. Cold muscles have poor blood supply; they are inelastic and easily injured. The best time to stretch is after training, when your muscles are warm and pliable. As mentioned above, I stretch after my hard aerobics session. If you want to stretch at other times, I suggest doing the brief general warmup routine described in Ripped 3, Lean for Life and Challenge Yourself -- before you stretch. I never do any form of exercise, including stretching, without warming up my muscles and joints.
Finally, donít overstretch. Iíve already said that stretching should not cause pain; if it hurts, donít do it. Thereís also another sign of overstretching of which you should be aware. In his book The Stark Reality of Stretching (revised addition, October 1999), Dr. Steven D. Stark says that overstretching does not always cause pain during the stretch. He suggests monitoring how you feel the next day or two. If you experience soreness, especially at the end of the muscle or in the joint, itís usually a sign of microscopic tearing in the muscle or connecting tissue.
If you experience pain during the stretch or soreness later, you are probably doing more harm than good. Keep in mind, however, that this type of soreness should be distinguished from the good soreness that results from endurance or strength training. Listen carefully to your body, and youíll be able to tell the difference.
I hope this helps. I wish you a speedy recovery and every success in your future training.
Ripped Enterprises, 528 Chama, N.E., Albuquerque, New Mexico 87108, Phone (505) 266-5858, e-mail: email@example.com, FAX (505) 266-9123. Office Hours: Monday-Friday, 8-5, Mountain time.
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