Tuesday, June 5, 2012

Hydration overhyped


Hydration overhyped, says new study

Our bodies need about two litres of fluids per day, not two litres of water specifically. In an Editorial in the June issue of Australian and New Zealand Journal of Public Health, Spero Tsindos from La Trobe University, examined why we consume so much water.
Mr Tsindos believes that encouraging people to drink more water is driven by vested interests, rather than a need for better health. “Thirty years ago you didn’t see a plastic water bottle anywhere, now they appear as fashion accessories.”
“As tokens of instant gratification and symbolism, the very bottle itself is seen as cool and hip,” said Mr Tsindos. He also discusses the role of water in our constant quest for weight loss. “Drinking large amounts of water does not alone cause weight loss. A low-calorie diet is also required.”
“Research has also revealed that water in food eaten has a greater benefit in weight reduction than avoiding foods altogether. We should be telling people that beverages like tea and coffee contribute to a person’s fluid needs and despite their caffeine content, do not lead to dehydration.”
“We need to maintain fluid balance and should drink water, but also consider fluid in unprocessed fruits and vegetables and juices.”

Exercise can trump hypertension genetics


Exercise can trump hypertension genetics, says new study

If your parents have a history of high blood pressure, you can significantly reduce your risk of developing the disease through moderate exercise and increased cardiovascular fitness, according to new research in the American Heart Association’s journal “Hypertension.”
The study, led by researchers at the University of South Carolina’s Arnold School of Public Health, found that those who had a parent with high blood pressure but were highly fit had a 34 percent lower risk of developing high blood pressure themselves, compared to those with a low-fitness level who had the same parental history. The study involved more than 6,000 people.
“Understanding the roles that family history and fitness play in chronic diseases is critically important,” said Robin P. Shook, the study’s lead author and an Arnold School doctoral student.
“The results of this study send a very practical message, which is that even a very realistic, moderate amount of exercise — which we define as brisk walking for 150 minutes per week — can provide a huge health benefit, particularly to people predisposed to hypertension because of their family history,” he said.
Previous research indicates that parental history accounts for about 35 percent to 65 percent of the variability in blood pressure among offspring, with varying levels of risk based on which parent developed it and the age of onset.
Researchers followed a group of 6,278 predominantly Caucasian adults 20 to 80 years old for an average 4.7 years. The participants were patients of the Cooper Clinic, a non-profit organization dedicated to preventive medicine, research and education in Dallas.
Thirty-three percent of participants reported that a parent had hypertension. When the study began, all participants were healthy, reported no physician diagnosis of hypertension, and achieved an exercise test score of at least 85 percent of their age-predicted maximal heart rate. Researchers determined participants’ cardiorespiratory fitness using a maximal treadmill exercise test.




During the study, 1,545 participants reported they had developed hypertension.
Researchers found that:
• Combining those with and without a family history of high blood pressure, high levels of fitness were associated with a 42 percent lower risk of developing hypertension, and moderate levels of fitness with a 26 percent lower risk.
• People with both a low level of fitness and a parent with hypertension had a 70 percent higher risk for developing hypertension compared with highly fit people with no parental history.
• Those with a high level of fitness and a parent with hypertension experienced only a 16 percent higher risk of developing hypertension compared to those who were fit and had no parental history.
“The correlation between fitness levels, parental history and risk are impossible to ignore,” Shook said. “This awareness can serve the clinician and the patient, as they work together to find effective and reasonable ways to avoid the diseases that have affected their family members — in some cases, for generations.”
The research findings may not apply to all people because the majority of the study participants were relatively fit, well-educated, middle- to upper-class white men.
The findings support the American Heart Association’s recommendations of moderately intense physical activity, such as brisk walking, for 30 minutes or longer at least five days a week.
The study’s co-authors included Duck-chul Lee, Xumei Sui, Vivek Prasad andSteven N. Blair, all from the Arnold School; Steven P. Hooker of Arizona State University; and Timothy S. Church of the Pennington Biomedical Research Center.
The National Institutes of Health and an unrestricted research grant from the Coca-Cola Company funded the study.

Milk ingredient protects against obesity


Milk ingredient protects against obesity in lab

Monday, June 4, 2012

How does exercise affect nerve pain?


How does exercise affect nerve pain?

Posted on  by Stone Hearth News

Exercise helps to alleviate pain related to nerve damage (neuropathic pain) by reducing levels of certain inflammation-promoting factors, suggests an experimental study in the June issue of Anesthesia & Analgesia, official journal of the International Anesthesia Research Society (IARS).
The results support exercise as a potentially useful nondrug treatment for neuropathic pain, and suggest that it may work by reducing inflammation-promoting substances called cytokines. The lead author was Yu-Wen Chen, PhD, of China Medical University, Taichung, Taiwan.
Exercise Reduces Nerve Pain and Cytokine Expression in Rats
Neuropathic pain is a common and difficult-to-treat type of pain caused by nerve damage, seen in patients with trauma, diabetes, and other conditions. Phantom limb pain after amputation is an example of neuropathic pain.
Dr Chen and colleagues examined the effects of exercise on neuropathic pain induced by sciatic nerve injury in rats. After nerve injury, some animals performed progressive exercise—either swimming or treadmill running—over a few weeks. The researchers assessed the effects of exercise on neuropathic pain severity by monitoring observable pain behaviors.
The results suggested significant reductions in neuropathic pain in rats assigned to swimming or treadmill running. Exercise reduced abnormal responses to temperature and pressure—both characteristic of neuropathic pain.
Exercise also led to reduced expression of inflammation-promoting cytokines in sciatic nerve tissue—specifically, tumor necrosis factor-alpha and interleukin-1-beta. That was consistent with previous studies suggesting that inflammation and pro-inflammatory cytokines play a role in the development of neuropathic pain in response to nerve injury.
Exercise also led to increased expression of a protein, called heat shock protein-27, which may have contributed to the reductions in cytokine expression.
Neuropathic pain causes burning pain and numbness that is not controlled by conventional pain medications. Antidepressant and antiepileptic drugs may be helpful, but have significant side effects. Exercise is commonly recommended for patients with various types of chronic pain, but there are conflicting data as to whether it is helpful in neuropathic pain.
The new results support the benefits of exercise in reducing neuropathic pain, though not eliminating it completely. In the experiments, exercise reduced abnormal pain responses by 30 to 50 percent.
The study also adds new evidence that inflammation contributes to the development of neuropathic pain, including the possible roles of pro-inflammatory cytokines. The results provide support for exercise as a helpful, nondrug therapy for neuropathic pain—potentially reducing the need for medications and resulting side effects.
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About the IARS
The International Anesthesia Research Society is a nonpolitical, not-for-profit medical society founded in 1922 to advance and support scientific research and education related to anesthesia, and to improve patient care through basic research. The IARS contributes nearly $1 million annually to fund anesthesia research; provides a forum for anesthesiology leaders to share information and ideas; maintains a worldwide membership of more than 15,000 physicians, physician residents, and others with doctoral degrees, as well as health professionals in anesthesia related practice; sponsors the SmartTots initiative in partnership with the FDA; and publishes the monthly journalAnesthesia & Analgesia in print and online.
About Anesthesia & Analgesia
Anesthesia & Analgesia was founded in 1922 and was issued bi-monthly until 1980, when it became a monthly publication. A&A is the leading journal for anesthesia clinicians and researchers and includes more than 500 articles annually in all areas related to anesthesia and analgesia, such as cardiovascular anesthesiology, patient safety, anesthetic pharmacology, and pain management. The journal is published on behalf of the IARS by Lippincott Williams & Wilkins (LWW), a division of Wolters Kluwer Health.

Altitude training: the science behind the conventional wisdom


Altitude training is a popular technique among athletes preparing for a competition, especially expert runners. Much research has been conducted on how to do it, at what altitude to train, how to modify workouts and how long to stay at altitude. However, a major unanswered question is when should an athlete return from altitude to compete?
Coaches of elite runners generally take one of two sides.
“They either believe an athlete should compete within 48 hours of coming back from altitude or in the 18- to 22-day range after returning,” said Robert Chapman, exercise physiologist in the School of Health, Physical Education and Recreation at Indiana University Bloomington. “But there is little scientific evidence showing why these coaches’ opinions are valid.”
His study, discussed on Thursday during the American College of Sports Medicine annual meeting on Thursday, suggests that both camps might be right.
About the study:
  • Six elite distance runners lived in Flagstaff, Ariz., for 28 days at an altitude of 2,150 meters. They followed a “live high, train low” altitude training program, which means that although the athletes lived at a high altitude, they trained at 1,000 meters to do harder and faster workouts a few times per week. After returning from the 28-day camp, the runners were tested over the course of 26 days. Researchers focused on testing heart rate, running economy and mechanics.
  • Physiological data shows that what most coaches say is true. Several variables showed that 48 hours is a good time to compete based on breathing results, while Day 7 and 13 showed more difficulty.

Chapman said this might be attributed to a concept referred to as ventilatory acclimatization.
“At altitude, a person breathes more, and that extra breathing stays with you when you come back down from altitude. Extra breathing uses more muscles, more energy, and the body has to work more to regulate blood flow,” he said.
This study suggests that an athlete may perform best at 18 to 22 days because the extra breathing goes away and the body gets re-acclimated to a lower altitude.
“This research will help athletes plan for major competitions,” says lead author Abby Laymon, graduate student in the School of HPER’s Department of Kinesiology. “For example, if an athlete is training for the Olympic trials, they can count backwards and plan their workout accordingly to perform their best after altitude training.”
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This study joins four others from IU that focus on altitude training. Future studies will determine why the physiological changes occur post-altitude.
The study, “Time-course of changes in cardiorespiratory measures post-altitude training: Implications for competitive endurance performance,” was discussed on Thursday during the High Altitude/Hypoxia I session.
Co-authors are Daniel P. Wilhite, Joseph W. Duke, Jonathon L. Stickford, Joel M. Stager and Timothy D. Mickleborough, all from the School of HPER’s Department of Kinesiology.