Weights plus walking equals more fit in less time

November 27, 2010 By admin

(Health.com) — Walkers who squeeze a bit of light weight training into their workout get more bang for their buck in terms of being fit and trim without increasing their total workout time, according to a new study of sedentary people with type 2 diabetes.

What’s more, those who mixed up their workouts showed the greatest improvement in blood sugar control after nine months, says Timothy S. Church, MD, Ph.D., of the Pennington Biomedical Research Center in Baton Rouge, Louisiana, who led the study.

“Our findings really support the 2008 federal physical activity guidelines, and our findings support those guidelines for everybody,” Church says.

These guidelines recommend people get at least 150 minutes of walking or 75 minutes of running a week, along with two or more days a week of resistance training.

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And that two days a week means a couple of 15- to 20-minute sessions on weight-training machines in the gym.

“It’s actually a pretty quick undertaking,” Church says.

Although exercise has long been recommended for people with diabetes because it can lower blood sugar almost as much as some medications, the best “prescription” for physical activity hasn’t been determined, Church and his colleagues write in the November 24 issue of the Journal of the American Medical Association.

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To find out, the researchers randomly assigned 262 sedentary men and women with type 2 diabetes to a control group that remained sedentary; an aerobic group that walked on a treadmill each week (equivalent to a brisk, 4 mph walk for 50 minutes 3 times a week); a resistance group that did three weight-training sessions per week (2 to 3 sets of 10 to 12 repetitions of 9 exercises); and a combo group that walked on the treadmill (42 minutes 3 times a week at 4 mph) and did two weight lifting sessions each week (1 set each of 9 exercises per session).

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The workouts were designed so that each would take about the same amount of time.

After nine months, the researchers estimated that the aerobic group worked out for an average of 140 minutes a week, the resistance group for 141 minutes, and the combination group for 140 to 150 minutes (110 minutes on the treadmill and 30 to 40 minutes lifting weights).

The key measurement Church and his team were looking at was hemoglobin A1c (HbA1c), a blood test that looks at the percentage of red blood cells that have glucose “stuck” to them and is a good measure of how well a person’s blood sugar has been controlled over the past two or three months.

The average HbA1c for the group was 7.7 percent at the beginning of the study. (Most guidelines recommend people with type 2 diabetes shoot for an HbA1c level of 7 percent or less.)

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Although HbA1c didn’t change significantly for people who did aerobic training only or resistance training only, it fell by 0.34 percent in the combination exercise group.

People in this group were also the only ones who showed a significant increase in their maximum oxygen consumption (which measures the capacity for aerobic exercise) compared to the non-exercising control group.

Men and women in all the exercise groups trimmed their waists by 2 to 3 centimeters (0.8 to 1.2 inches). The weight lifters lost an average of 1.4 kilograms (3.1 pounds) of fat compared to the control group, while the combination exercisers lost 1.7 kilograms (3.7 pounds) of fat compared to their sedentary peers.

The reduction in HbA1c seen in the combination exercisers would translate to a 5 percent to 7 percent reduction in heart disease risk, according to Church and his colleagues.

It would also slash the risk of so-called microvascular complications, such as damage to the eyes, nerves, and kidneys, by 12 percent, the researchers say.

Although several studies have looked at exercise for diabetes, the current investigation is unique for its long duration, as well as the fact that it included an ethnically diverse group of patients, says Ronald J. Sigal, M.D., of the University of Calgary in Alberta, Canada. African Americans made up 44 percent of study participants; nearly two-thirds were female.

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Sigal co-authored an editorial accompanying the new study, but wasn’t involved in the current research. In 2007, he and his colleagues published the DARE trial, which showed that resistance training plus aerobics was the most beneficial approach for people with diabetes.

“Unlike the DARE trial, they made a real effort to keep the total time involved the same” in the new study, Sigal says.

Resistance exercise likely increases the size of muscle fibers, while aerobic exercise boosts muscle’s efficiency in using glucose, which explains why combining the two has the strongest effect on blood sugar control, Sigal says.

“What’s the biggest consumer of blood sugar in the human body? Well, it’s muscle,” Church says. “If your body chews up more sugar, you’ve got less sugar in the blood and your diabetes is better. You’re kind of stimulating two different systems in the muscle.”

Sigal says the kind of resistance training people did in his study and Church’s study isn’t something you can accomplish at home with a few sets of dumbbells. (The study participants did their exercises under a trainer’s supervision at a gym.)

“It’s not realistic for most people to have the quality and variety of equipment at home that they could get at a gym,” he says.

Another benefit of going to the gym, he added, is that you can get help from trainers, who will push you to do more.

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Although trainers are great for some people, Church says, other people want nothing to do with them.

“If there’s one thing I’ve learned about exercise, it is such a personal thing,” he adds. “What’s the best type of aerobic exercise? The one that you’ll do.”

About 24 million people in the U.S. have diabetes, and 90 percent of those cases are type 2 diabetes, which is more likely to occur with aging, excess weight and a sedentary lifestyle.

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Best diabetes fitness plan: aerobics plus weights

November 26, 2010 By admin

CHICAGO – People with diabetes should mix aerobics with weight training to get the best results in lowering blood sugar, a new study suggests. The combination worked best for weight loss too, compared to aerobics or weight training alone.

Blood sugar is fuel to muscles, and more sugar is burned during aerobic activity. Weight training builds more muscle, and both activities change muscle proteins in ways that enhance the process.

“It’s clear that doing both aerobic and strength training is superior to either alone,” said lead author Dr. Tim Church of Pennington Biomedical Research Center in Baton Rouge, La. “It’s almost like taking two different drugs.”

Patients in the study, published in Wednesday’s Journal of the American Medical Association, achieved the results over nine months, exercising three days a week for about 45 minutes each session.

“People can manage this amount of exercise,” said Laurie Goodyear of Joslin Diabetes Center in Boston, who wasn’t involved in the new study but does similar research. “They didn’t have to go on a diet. This was purely an exercise effect.”

The researchers’ goal was to test three exercise programs that doctors could realistically recommend and patients could stick with. They compared aerobics alone, weight training alone and a combination. U.S. guidelines recommend aerobics and weight training combined for all adults.

All three groups worked out for about the same amount of time. A fourth group of patients was offered only weekly stretching and relaxation classes for further comparison. The study was completed by 245 people with diabetes.

Led by trainers, patients walked on a treadmill that raised the uphill grade by 2 percent every two minutes for the aerobics. Weight training, also supervised, was done on machines that worked muscles in the upper body and legs, with more weight added as participants increased their strength.

“It gave me a lot more energy. That was one of the first things I noticed,” said Deidra Atkins-Ball, 44, a biology professor, diagnosed with diabetes a year before she joined the aerobics-weights group.

A distant aunt with diabetes lost both legs and her vision to the disease. Too much blood sugar can damage nerves, eyes, the heart and blood vessels.

“I remember as a kid having to do things for her, going to the store for her,” Atkins-Ball said. “It really scared me.”

The researchers found that only the group that combined aerobics and weights both lowered their blood sugar and lost weight, although all three fitness groups reduced their waist sizes.

Fewer patients in the combo group started taking new diabetes drugs than in the other groups. Decisions on medications were left up to the patients’ regular doctors during the study.

Forty-one percent of the patients in the combo group either decreased their diabetes medications or lowered their average blood sugar as measured by a common blood test, compared to 26 percent for weights only, 29 percent for aerobics only and 22 percent in the non-exercise group.

The blood sugar reduction achieved by the combo group was enough to reduce the risk of heart attacks, strokes and other complications, the researchers wrote, citing earlier studies.

Atkins-Ball’s results were good, if not long-lasting. She dropped 4 pounds and saw her blood sugar reach near normal levels. When the program ended, she joined a gym and kept exercising — for a while.

Then she got busy, let her gym membership lapse after a year and has seen her blood sugar levels climb. She’s now taking two diabetes drugs, instead of the one she took during the study.

Atkins-Ball is trying to get back into an exercise routine by walking two miles with her husband in the mornings. Her advice for others with diabetes is to get into a structured exercise program.

“That’s what helped me the most,” she said.

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