Monday, August 06, 2012

Students With Strong Hearts and Lungs May Make Better Grades

This seems pretty good support for the idea that there is a general syndrome of biological fitness, of which IQ is one part

Having a healthy heart and lungs may be one of the most important factors for middle school students to make good grades in math and reading, according to findings presented at the American Psychological Association's 120th Annual Convention.

"Cardiorespiratory fitness was the only factor that we consistently found to have an impact on both boys' and girls' grades on reading and math tests," said study co-author Trent A. Petrie, PhD, professor of psychology and director of the Center for Sport Psychology at the University of North Texas. "This provides more evidence that schools need to re-examine any policies that have limited students' involvement in physical education classes."

The researchers gathered data at five Texas middle schools from 1,211 students, of whom 54 percent were female with an average age of about 12. Overall, the group was 57 percent white. Among the boys, the breakdown was 57.2 percent white, 24.2 percent Mexican-American, 9.1 percent African American, 1.1 percent Asian-American and 1.2 percent American Indian. For the girls, 58.6 percent were white, 23.4 percent were Mexican-American, 9.2 percent were African-American, 2.3 percent Asian-American and 0.6 percent were American Indian.

While previous studies have found links between being physically fit and improved academic performance, this study also examined several other potential influences, including self-esteem and social support. It also took into account the students' socioeconomic status and their self-reported academic ability, Petrie said.

In addition to cardiorespiratory fitness, social support was related to better reading scores among boys, according to the study. It defined social support as reliable help from family and friends to solve problems or deal with emotions. For girls, having a larger body mass index was the only factor other than cardiorespiratory fitness that predicted better reading scores. For boys and girls, cardiorespiratory fitness was the only factor related to their performance on the math tests. "The finding that a larger body mass index for girls was related to better performance on the reading exam may seem counterintuitive, however past studies have found being overweight was not as important for understanding boys and girls performances on tests as was their level of physical fitness," Petrie said.

From one to five months before the students were to take annual standardized reading and math tests, they answered questions about their level of physical activity, and how they viewed their academic ability, self-esteem and social support. The school district provided information on the students' socioeconomic status and reading and math scores at the end of the year.

To determine students' physical fitness, the researchers worked with physical education teachers to administer a fitness assessment program widely used in U.S. schools. The program includes a variety of tests to assess aerobic capacity, muscular strength, muscular endurance, flexibility and body composition. The assessment provides an objective measure of cardiorespiratory fitness through the Progressive Aerobic Cardiovascular Endurance Run, or PACER, and body composition through measuring BMI, the study said.

"Because this is a longitudinal study, these variables can now be considered risk factors in relation to middle school students' performance on math and reading examinations," Petrie said. "And that is essential to developing effective programs to support academic success."


A starvation diet could actually be good for you - and make you live longer

This has been known from animal studies for many years but it seems to be reaching a wider audience these days

Tomorrow, a BBC TV Horizon investigation looks into the health benefits of fasting.

Science reporter Michael Mosley speaks to scientists who have discovered that periods of eating very little or nothing may be the key to controlling chemicals produced by the body linked to the development of disease and the ageing process. This backs up  recent studies on animals fed very low-calorie diets which found the thinnest (without being medically underweight or malnourished) are the healthiest and live the longest.

The key, say researchers at the University of Southern California’s Longevity Institute, is the hormone Insulin-Like Growth Factor 1 (IGF-1). Mosley explains: ‘IGF-1 and other growth factors keep our cells constantly active. It’s like driving with your foot on the accelerator pedal, which is fine when your body is shiny and new, but keep doing this all the time and it will break down.’

According to Professor Valter Longo, director of the Longevity Institute, one way to take the foot off the accelerator, and reduce IGF-1 levels dramatically – as well as cholesterol, and blood pressure – is by fasting.
Controversial theory: The reason experts haven¿t emphasised this is that they don¿t want to trigger eating disorders or demotivate the overweight trying to get into the healthy weight range

Controversial theory: The reason experts haven¿t emphasised this is that they don¿t want to trigger eating disorders or demotivate the overweight trying to get into the healthy weight range

‘You need adequate levels of IGF-1 and other growth factors when you are growing, but high levels later in life appear to lead to accelerated ageing,’ he says. ‘The evidence comes from animals such as the Laron mice we have bred which have been genetically engineered so they don’t respond to IGF-1. They are small  but extraordinarily long-lived.’

The average mouse has a life span of two years – but the Laron typically live 40 per cent longer. The oldest has lived to the human equivalent of 160. They are immune to heart disease and cancer and when they die, as Prof Longo puts it: ‘They simply drop dead.’

During the film, Mosley tries various fasts – for three days straight, and for two days a week, for six weeks – with dramatic results. Not only does he lose weight, but his cholesterol levels and blood pressure improve. These findings chime with recent reports that reaching a ‘healthy’ Body Mass Index (BMI) may not be enough – we need to be as slim as possible to reduce our risk of illness.

The reason experts haven’t emphasised this is that they don’t want to trigger eating disorders or demotivate the overweight trying to get into the healthy weight range. There is only so long, however, we can shy away from this because the evidence keeps mounting.

Matthew Piper, of the Institute of Healthy Ageing, University College London, says: ‘Studies on monkeys show if we restrict the diet there is a delay in the onset of cancer, coronary heart disease and diabetes in later life as well as staving off dementia.’

Reducing our food intake over months or years could boost lifespan by 15 to 30 per cent, experts believe.

You can eat pretty much what you want, but the catch is that you have to go through periods of fasting.

I’ve always followed medical advice: never crash diet. But after speaking to Professor Valter Longo, who has been studying the health benefits of fasting, I agreed to try it.

I fasted for just over three days. I ate nothing at all for 82 hours, but drank plenty of water and black tea, plus one cup of low-calorie soup a day. It wasn’t much fun, but I didn’t get any headaches, I slept fine and I felt energetic throughout.

At the end, I had missed out on about 7,500 calories worth of meals. Since you need to cut your food intake by about 3,500 calories to lose 1lb of fat, that means I’d lost just over 2lb of flab.

I also had my blood tested and my levels of the hormone IGF-1 – which scientists believe is linked to ageing – were significantly lower than before.

This, says Valter, is the key to how fasting helps prolong lifespan. The lower our IGF-1, the less likely we are to develop a host of diseases.

The problem was I couldn’t see myself doing three-day fasts regularly, so I tried out something less extreme. I met Dr Krista Varady, of the University of Illinois, Chicago. She explained the merits of Alternate Day Fasting (ADF).

One day you eat whatever you want, the next day you fast. Even on my fasting days I would be allowed about 600 calories.

She said: ‘We recently finished a trial that looked at two different groups, about 16 people in each, doing ADF for ten weeks. We put one group on a low-fat diet, eating lean meats fruits and vegetables. The other group were eating lasagne and pizza. Both groups lost weight but the people eating high-fat meals lost the same amount of weight as those eating low-fat meals.’

And it wasn’t just weight loss. Both groups saw similar falls in the ‘bad’ cholesterol, LDL, and in blood pressure.

I gave it a go, but found it too hard and ended up doing a 600-calorie fast one or two days a week.

I started out at 13½ st. After six weeks on my new regime, I have lost 20lb. My cholesterol, blood glucose and IGF-1 have all improved markedly.

I do believe that with intermittent fasting I can slow down my cells and extend my healthy years. So I plan to stick with it.



Anonymous said...

There are lots of people around the world who are subsisting on calorie intakes below 1000 calories per day. They do not show any signs of outliving their better fed fellows. This is just another piece of half arsed control freakery.

Unknown said...

Benefits of IGF 1

Starvation diet and slimming plans have drifted out of fashion in the past few decades. Crash diets are supposed to slow your metabolism down, leading to more weight gain when you stop.