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Volume 5, Issue 2
Interval training reduces risk of metabolic syndrome
People who suffer from metabolic syndrome are three times more likely to die of heart disease than people who do not have the condition, experts say. Metabolic syndrome is characterized by having at least three of the following traits: excessive abdominal fat, high triglyceride levels, low HDL ÒgoodÓ cholesterol, high LDL "bad" cholesterol, elevated blood pressure and insulin resistance or glucose intolerance. Though it is known that exercise can reduce all of these conditions, a new study conducted in Norway suggests that a specific type of exercise can further reduce one's risk of metabolic syndrome.
For four months, researchers followed 32 people with metabolic syndrome. The subjects were divided into three groups: aerobic interval training, continuous moderate exercise, or no exercise. The patients in the exercise groups walked or ran on a treadmill three times per week. Those in the interval training group exercised for a period of 40 minutes, continually varying their heart rate while the continuous moderate group exercised steadily for 50 minutes. Although both exercise groups lost the same amount of weight and experienced a similar decrease in blood pressure, the interval training group had much lower triglyceride levels, better insulin response and overall circulatory function and increased their HDL "good" cholesterol increased by about 25%.
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Overweight and diabetes can lead to male infertility
Being overweight is associated with a myriad of conditions and diseases including diabetes, heart disease and certain cancers, just to name a few. Now, a report from Northern Ireland adds another negative consequence of overweight to that list: overweight and diabetes are linked to male infertility. The National Association for Infertility classifies infertility as a disease. It is a common problem; approximately 10 to 15 percent of couples are infertile, and half of all cases of infertility are due to male factors.
A team of researchers examined semen samples from overweight, diabetic men and compared them to semen samples from normal weight, non-diabetic men. They found that diabetics have a significantly higher percentage of sperm with DNA damage. Sperm DNA quality is linked to decreased embryo quality, low embryo implantation rates, higher miscarriage rates and childhood diseases. The authors of the report conclude that overweight men with diabetes have lower fertility rates and that even when pregnancy does occur, damaged sperm can lead to problems with the pregnancy and the child's health.
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Yoga and meditation trigger genetic changes to reduce stress
The American Institute of Stress characterizes stress as "America's #1 health problem" and associates it with a host of diseases. Practices such as yoga, tai chi and meditation have been used worldwide for thousands of years to increase relaxation and manage stress. A recent study conducted at Massachusetts General Hospital sheds some light on how stress-reducing activities can actually help fight disease. These activities trigger what is known as the relaxation response, which is characterized by decreased oxygen consumption and reduced psychological distress.
Researchers divided 58 subjects into three groups: long-term practitioners of daily relaxation response-inducing activities, individuals who completed 8 weeks of relaxation training and a control group. The researchers assessed participants' blood samples and used this data to compare gene expression patterns between groups. The study found that more than 2,200 genes were activated differently in the long-time practitioners relative to the controls. There were also significant cellular differences that suggested that the relaxation response triggered genetic changes that decreased stress. The researchers concluded that daily activities such as yoga and meditation can prevent diseases that are related to chronic psychological stress.
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Many people in denial about being overweight
Though rates of obesity and overweight are steadily rising, the number of people who recognize themselves as overweight or obese is actually decreasing. The Centers for Disease Control and Prevention state that it is important for people to know their BMI and compare it to that of the general population; awareness is an important factor in making lifestyle changes in order to maintain a healthy weight. However, a large study conducted in England indicates that more and more people are in denial about their weight.
Researchers from the Health Behaviour Research Centre at University College London compared data taken from two household surveys given to a representative sample of the British population. The first was given in 1999 to 1797 people and the second was given in 2007 to 1836 people. In both surveys, participants were asked to give their height and weight and then categorize themselves as either 'underweight,' 'about right,' 'overweight,' or 'obese.' In 1999, 81% of overweight participants correctly identified themselves as overweight compared with 75% in 2007. The researchers attribute this trend to the overall increase in overweight around the world, which makes the condition more socially acceptable and prevents people from recognizing that they are at risk for a host of weight-related conditions.
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Being fit decreases brain damage caused by Alzheimer's disease
Alzheimer's disease causes dementia, brain atrophy, destroys brain cells, weakens memory and is currently the sixth-leading cause of death in the United States. According to the Alzheimer's Association, nearly 5 million Americans are living with the disease. There is much evidence that physical activity can be beneficial as people age, especially to those with Alzheimer's. Researchers at the University of Kansas School of Medicine conducted a study to determine the impact of exercise on Alzheimer's patients' brain structure.
The study consisted of 64 healthy subjects and 57 subjects with early-stage Alzheimer's. Peak oxygen consumption tests were taken during treadmill tests to evaluate subjects' cardiorespiratory fitness and an MRI was taken to estimate brain atrophy. When researchers assessed the relationship between physical fitness and brain capacity they found that individuals with Alzheimer's who were less physically fit had four times more brain shrinkage than those who were more fit. However, in healthy subjects, fitness had no effect on brain capacity. These results led authors to conclude that physical fitness significantly decreases the brain atrophy that is a common in Alzheimer's sufferers.
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Sources
1Tjonna AE et al. (2008). Aerobic interval training versus continuous moderate exercise as a treatment for the metabolic syndrome: A pilot study. Circulation, epub.
2The Annual Conference of the European Society of Human Reproduction & Embryology.
3Dusek JA et al. (2008). Genomic counter-stress changes induced by the relaxation response. PLoS One, 3(7), e257.
4Johnson F, Cooke L, Croker H and Wardle J. (2008). Changing perceptions of weight in Great Britain: Comparison of two population surveys. BMJ, 337, a494.
5Burns JM et al. (2008). Cardiorespiratory fitness and brain atrophy in early Alzheimer disease. Neurology, 71, 210-216.
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