Tuesday, April 22, 2008

Treadmill Workout Good for Chronic Stroke Survivors

Treadmill exercise by stroke survivors can benefit their hearts and brains, a group of researchers found.
Most people know that regular exercise improves fitness, lowers blood pressure and burns calories. There is widespread agreement that physical activity is good for everyone, and that exercise is one of the best ways to stave off many miseries that accumulate with the passing years. And when people do have heart attacks or break bones, exercise is a key component in rehabilitation.
But maybe not for stroke. Most doctors believed that after several months people trying to regain function after a stroke had gone as far as they were going to. If people didn’t get better after half a year they simple weren’t going to.
Recent research demonstrated that although there may be plateaus in the course of recovery, exercise can improve function years after the stroke occurred.
Findings appeared in the March issue of the Cleveland Clinic Journal of Medicine.
The research, led by Andreas Luft of Germany’s University of Tubingen and a group of Baltimore scientists, examined the effect of six months of treadmill exercise training in university labs in chronically disabled stroke survivors.
Treadmill exercise improves fitness and walking ability in patients when initiated 6 months or more following stroke, the research found. Rapid improvement, even with rehabilitation, is rare. Between 80 percent and 90 percent of stroke survivors have a motor deficit, with walking impairments the most common. Most stroke survivors also have diminished fitness capabilities.
The study looked at peak oxygen consumption during treadmill walking between stroke survivors and healthy, but sedentary volunteers. The stroke survivors had approximately 50 percent lower levels of peak fitness- using 75 percent of their functional capacity compared with 27 percent with the healthy volunteers. Stroke volunteers also showed a poorer gait and required greater oxygen consumption to sustain their walking speeds.
The clinical program the volunteers participated in lasted 6 months and involved moderate activity training, primarily on the treadmill. The program’s lower-limb workouts include using a treadmill modified with handrails and other safety devices, as well as stair-stepping, shifting weight from foot to foot, and other exercises tailored to the patient’s abilities. The upper extremity exercises include reaching, grasping, and other repetitive movements.
For the study, 32 chronically disabled stroke survivors took part in the research. The volunteers participated in the treadmill program three times a week.

Source: Luft et. al “Post-stroke exercise rehabilitation: What we know about retraining the motor system
and how it may apply to retraining the heart.” Cleveland Clinic Journal of Medicine, Vol. 75, Supplement 2, March 2008, S83

Diabetes Medication Can Help Heart Health

The type of medicine matters when it comes to heart health among diabetics.
A new study has found evidence that medications that lower blood sugar levels can slow the progression of a condition that can lead to heart attacks.
Known as the PERISCOPE trial, the study looked at 543 patients with coronary disease and type 2 diabetes to see how insulin producing drugs compared with insulin providing drugs in combating coronary atherosclerosis, a build up of fat deposits in the artery walls that can lead to stroke or heart attack.
Dr. Steven E. Nissen of the Department of Cardiovascular Medicine at Cleveland Clinic Foundation was the lead author of the study, which was published in the April 2 issue of the Journal of the American Medical Association.
The research demonstrates for the first time the ability of a blood sugar lowering medication to slow the artery buildup in patients with diabetes. Cardiovascular diseases are the cause of death in approximately 75 percent of patients with diabetes.
Patients with diabetes often take oral medications to lower their blood sugar levels. There are two main types of drugs that function quite differently. One type of drug simulates insulin secretion, known as secretagogues. The other type of drug reduces insulin resistance, known as insulin sensitizers.
The research compared the effects of pioglitazone, a type of insulin sensitizer, with that of glimepiride, an insulin secreting drug, on the progression of the artery wall fat buildup in patients with Type 2 diabetes.
Treatment with the insulin sensitizer resulted in a lower rate of progression of coronary atherosclerosis compared with the insulin secreting drug in patients with type 2 diabetes and coronary artery disease, the study authors conclude.
The 543 patients with coronary disease and type 2 diabetes, who participated in the double-blind, randomized trial at 97 hospitals in North and South America, received the insulin secreting drug for 18 months.
To be eligible, patients had to be age 35 to 85 with a HbA1c, measure of blood sugar, level between 6.0% and 9.0%, if taking a blood sugar lowering medication or a 6.5% to 10% if not on medication. Patients were excluded if they had uncontrolled high blood pressure or liver disease. Participants were tested beforehand to make sure less than half of their arteries were blocked.
In addition to slowing the progression of coronary atherosclerosis, participants registered cholesterol and blood pressure levels below the target guidelines for patients with diabetes.

Source: Nissen et al., “Comparison of Pioglitazone vs. Glimepiride on Progression of Coronary Atherosclerosis in Patients with Type 2 Diabetes.” April 2, 2008 Journal of American Medical Association.

Thursday, April 17, 2008

Conversation with Howard Eichenbaum

Howard Eichenbaum describes himself as “cognitive neuroscientist.”
The Boston University researcher combines biology and psychology for his job, which is a cross between psychologist and neuroscientist.
As part of the Center for Memory and Brain, Eichenbaum studies rats’ brains to learn how memory functions in animals, including humans. Eichenbaum hopes that understanding psychology and biology can help researchers make strides in alleviating human memory loss.
Eichenbaum earned an undergraduate degree in biology before he switched to psychology in graduate school. He obtained both degrees from the University of Michigan, before doing his postdoctoral fellowship at the Massachusetts Institute of Technology.
Eichenbaum works as a faculty member in the Department of Psychology at Boston University. The field of biopsychology began to emerge while Eichenbaum was in graduate school.
Biopsychology, sometimes referred to as psychobiology, arose from the identification of brain areas involved in certain behaviors and emotions three decades ago; from the discovery in the 1950s that some psychological problems can be treated chemically; and from identifying chemicals, called neurotransmitters, that pass messages from one brain cell to the next.
After studying biopsychology, Eichenbaum decided to pursue an approach that combines both biology and psychology in his own research. In his studies, Eichenbaum takes a molecular biology approach in learning the electrical activities of the neurons of the brain. He uses his biological background to understand the brain’s circuitry in order to identify what happens with the synapses and neurons, in essence how neurons communicate with one another.
From a psychologist standpoint, Eichenbaum concerns himself with human behavior. In particular, Eichenbaum wants to examine memory, known as conscious recollection. He studies how people remember the order of events and how the brain can code sequence of events and play it back again.
Understanding the brain could help address memory disorders, common in aging, as well as diseases such as Alzheimer’s, Eichenbaum says.
Biology could also play a role in creating cures for such conditions. Researchers believe that a protein called beta-amyloid that builds up into plaques in the brain and kills nerve cells, could be at the root of Alzheimer’s. Drug studies are being done to attempt to break up this process, which is known as “amyloid cascade.” One anti-inflammatory drug being tested for its potential as an Alzheimer’s drug would target the enzyme, called gamma secretase that is believed to play a role in the amyloid build-up. Several drugs originally approved for other diseases, such as diabetes and prostate cancer, attempt to modify the brain processes that cause Alzheimer’s even though the processes aren’t fully understood.
Scientists have identified proteins responsible for strengthening the gaps where information is exchanged between neurons.
Understanding cell interaction in the brain could lead to new strategies for memory preservation to combat disease or aging, Eichenbaum says.

Conversation with Yu-Ling Shao

The Erickson Foundation, a Baltimore-based private foundation established in 1998, conducts aging research and wellness programs for older adults.
The Foundation wants to develop legitimate aging research, says Yu-Ling Shao, the foundation’s coordinator of research and new ventures.
Shao has been with the Foundation since 1999. He studied biology and chemistry as an undergraduate student and earned a graduate degree in hospital administration before moving to his current role.
Shao conducts research into aging issues, studying bone strength, balance and osteoporosis among other issues. The Foundation wants to be on the frontlines of creating a wellness program for older adults, Shao says.
The Foundation often partners with researchers from universities to develop new programs. For example, the group paired with aging researchers at California State University-Fullerton to develop a program designed to reduce physical frailty and the number of falls among older adults. Known as FallProof!, the structured balance and mobility training program, has been taught to employees at Erickson Communities, operator of retirement homes across the country. Balance and mobility disorders resulting in falls among the aging population pose a serious public health problem in the United States, Shao says.
While separate entities, The Erickson Foundation often uses Erickson Retirement communities as a test bed for their aging research initiatives, Shao says.
Many of the senior citizens have also taken to using the fitness equipment offered at the retirement centers and participating in health programs.
The Foundation also wants to study video games and virtual reality equipment.
“Gaming has true potential to become a legitimate tool in the toolbox of the health-medical professional,” Shao says.
Nintendo's Wii game console has been widely used at Erickson communities but primarily for socialization and fun, not rehabilitation.
The residents at Sedgebrook, an Erickson community located near Chicago, got a Wii system in December 2006.
“They are truly the ones that started the rage here,” says Erickson spokeswoman Kate Newton Schmelyun. “Their enthusiasm for the game is completely infectious.” The 17 other communities received systems in mid-2007.
While each community has at least one gaming system for residents to play, several have more than one system, and have organized leagues and regular events around the Wii.
“The vast majority of our residents live completely independently, but we also have assisted living and skilled nursing neighborhoods at each campus, and those residents play Wii, too,” Schmelyun says.
Shao says the Wii has the potential to help stroke patients regain some muscle function.
“There is a beauty to the Wii and other types of systems for folks who really through injjury or diseases have lost the ability to move their muscles,” Shao says.
While the Wii simulates full body movement without the regular effort levels, ultimately the Nintendo game console was designed for entertainment value. The Wii doesn't offer cardiovascular component for those who have the ability to regularly perform the tasks, such as bowling or tennis, Shao says.
Other companies are developing products to work along with video games. For example, Cateye Game Bike is a stationary bicycle that can connect to the four main video game systems to provide an interactive virtual reality experience.
The Game Bike has heart rate control programs that allow the user to track the maximum heart rate.
“This type of gaming system may not be for everyone, but one developing argument is that for older adults who are able or willing to engage in light to moderate physical activity in a gaming context, efforts should be made to include it,” Shao says.

Sunday, March 9, 2008

Resistance Training Can Make You Younger

Older adults who lift weights are biologically younger, according to recent research published in the Public Library of Science One.
The work by lead author Simon Melov of the California-based Buck Institute for Age Research and his colleagues, “Resistance exercise reverses aging in human skeletal muscle,” explored whether resistance training, like lifting weights, can reverse aging.
Such exercise can lead to a younger physiological age, the study found.
Researchers looked at genes and muscle strength of some healthy older and younger adult men and women. Some of those had muscle samples taken before and after a six-month resistance exercise-training program.
Resistance exercise training was performed twice weekly on non-consecutive days for 26 weeks in 14 older individuals. Participants stretched and did 3 sets of 10 repetitions for leg press, chest press, leg extension, leg flexion, shoulder press, lat pull-down seated row, calf raise, abdominal crunch, and back extension and 10 repetitions for arm flexion and arm extension.
Before exercise training, older adults were 59% weaker than younger adults, but after six months of training in older adults, strength improved significantly such that they were only 38% lower than young adults, the research found.
Eesearchers examined 596 genes. After exercise, the gene signatures reverted to younger levels for genes affected by age and exercise.
Human aging is associated with muscle atrophy, known as sarcopenia, weakness and functional impairment, Approximately 7 percent of adults over 70, and up to 20 percent over age 80 years have debilitating conditions as a result of atrophy. The estimated annual cost of sarcopenia-related health issues to the US health care system is more than $18 billion annually.
Resistance exercise can increase muscle strength, function and mass in older adults even in their 90s.
Melov et al.’s research also found that exercise reverses a functional decline in the elderly, that gene expression changes associated with aging are reversed to youthful levels after 6 months of exercise training and that exercise is more likely to affect “aging” genes than genes not associated with age.

Citation: Melov S, Tarnopolsky MA, Beckman K, et al. Resistance exercise reverses aging in human skeletal muscle. PLOS ONE 2007; 2(5):e465 [www.plosone.org].

Saturday, March 8, 2008

Molecular Causes of Physical Inactivity Needs More Study, Scientists Say

Not being active can change your body for the worse. And while we already know much about what can happen, a pair of researchers at the University of Missouri want to know how and why the body adapts to physical inactivity.
Physical inactivity is a basic biological question that deserves more attention, write Frank W. Booth and Simon J. Lees in their 2007 article, "Fundamental questions about genes, inactivity, and chronic disease" published in the Physiological Genomics journal.
There is a biological basis for the current epidemics of obesity and chronic diseases like Type 2 diabetes.
"In the case of chronic disease caused by physical inactivity, we need not complicate matters by producing separate drugs for each of the benefits afforded by physical activity when physical activity is already the answer," Booth and Lees write in the journal article.
The journal authors, both researchers in the department of biomedical sciences and at the Health Activity Center at the University of Missouri, argue that determining how and why physical activity causes the body to adapt to inactivity would be a better use of time spent.
There have been increased incidences of chronic disease triggered, at least in part, by physical inactivity. For example, the CDC has recognized that physical inactivity is an "actual cause" of diabetes. The molecules for the "actual cause" need to be identified, Booth and Lees argue.
For example, understanding how and why physical inactivity produces low insulin sensitivity could make clear a cause of type 2 diabetes, they say.Providing molecular evidence of chronic diseases would allow scientists and health officials to further promote physical activity as a means of preventing chronic disease, potentially allow early detection and provide society with the information needed to counter the increasing amounts of physical inactivity in our daily lives.
More than 50 percent of American adults do not get enough physical activity to provide health benefits and 25 percent of adults are not active during their leisure time. Furthermore, two-thirds of children in grades 9th through 12th do not meet minimum physical activity requirements.
Researchers have documented all the negative risks associated from physical inactivity. Physical inactivity increases the risk of coronary artery disease by 45 percent, stroke by 60 percent, hypertension by 30 percent and osteoporosis by 50 percent. Physical inactivity can lead to obesity, falls in the frail and elderly, depression and anxiety disorders. There is also some evidence that physical inactivity increases dementia and harms school academic performance. In an extreme state, such as constant bed-rest, bones lose density and muscles can shrink.
Scientists are only recently starting to document evidence of the gene interactions that result from physical inactivity.There are some documented epidemiological examples of physical inactivity-gene interaction leading to a chronic disease.
For example, there is a known hereditary risk involved with Type 2 diabetes. The Harvard Nurse's study reported that women with parents with Type 2 diabetes had a higher risk of Type 2 diabetes than did women whose parents did not have Type 2 diabetes. Among those women whose parents had diabetes, the 20 percent most inactive had a 65 percent greater risk of diabetes than the women who were most active.
Evidence exists that lifestyle change among diabetics can improve their health more than drugs.In the U.S. Diabetes Prevention Program, the lifestyle intervention group (weight loss, diet and physical activity) was about twice effective as the drug. The incidence of Type 2 diabetes was reduced by 58 percent with the lifestyle intervention and by 31 percent with metformin, a diabetes drug used to control blood sugar levels.
In the past, humans had to be physically active in order to survive. With technological advances, automation has eliminated the need for humans to "hunt" and "gather.
"The challenge for researchers, according to Booth and Lees, is to see whether "stone age" genes can be made modern, or to see if "stone age" genes work in the "space age."

Citation:Frank W. Booth and Simon J. Lees
Fundamental questions about genes, inactivity, and chronic disease
Physiological Genomics 28: 146-157, 2007

Diet and Activity Can Help Diabetics In A Short Amount of Time

If you have a chronic disease such as diabetes, you can improve your health without losing weight and do so in a matter of weeks, according to recent medical findings.
An article in the May 2006 issue of the Journal of Applied Physiology, "Physical activity and dietary intervention for chronic diseases: a quick fix after all?" by Frank W. Booth and Manu V. Chakravarthy discussses how high fiber diets have been shown to lower insulin levels.
Also, an intense change in diet and physical activity can cut the chance of developing diabetes in half.
The journal authors discuss a study by Roberts et. al's in the same journal that shows how a 3- week treatment program showed a 50 percent decrease in metabolic syndrome and type 2 diabetes.
At the start of the study, 42 percent of the 31 subjects had Type 2 diabetes. This number dropped to 23 percent after the three week trial. An intense change in diet and increased physical activity contributed to the solution.
Participants' diet was light on fat, medium on protein, high on unrefined carbohydrates and fiber. The physical activity regiment, on the other hand, consisted of 45-60 minutes per day of walking on a treadmill at a heart rate of 70-85 percent of maximium. All the activities took place in a 21-day program at the Pritikin Longevity Center.
The change in lifestyle resulting from the high-fiber, low-fat diet and physical activity reduced stress levels and inflammation associated with Type 2 diabetes in obese men. All this improvement took place despite a 3.6 and 2.8 percent decrease in body weight and body mass index.
The journal authors conclude that the 3-week intense lifestyle change can result in a marked improvement in health without a major change in body mass. Much of the analysis, however, focuses on the study which featured 31 male subjects tested in 2001.
For long-term health benefits the focus should be on improving fitness by increasing physical activity, rather than relying on diet or weight control, Booth and Chakravarthy argue.
"These comments are important because the role of physical activity in health seems to be emphasized less than diet and obesity by the popular media."