Friday 30 September 2011

Exercise: The male-female divide

While we know exercise is good for us, many researchers continue to investigate exactly how it affects our nervous system. One of the moest interesting studies conducted recently includes a look at the patterns between the sexes, which is revealing how differences affect blood flow and oxygen delivery to skeletal muscles.

Led by Emma Hart, Ph.D., a research fellow under Dr. Michael Joyner at the Mayo clinic, the research team’s study reveals a difference in how nerve traffic (nerve pulses per minute) influences the way men and women regulate blood pressureT

The findings may have important implications for understanding how hypertension and other disorders of blood pressure regulation occur in men and women. “We took some young men with variable nerve traffic and showed that people with very high nerve traffic had constricted blood vessels but a lower cardiac output, and that was one of the factors that kept them from having high blood pressure,” says Dr. Joyner. In young women this relationship was absent. “It’s an indication that the women’s blood vessels and cardiovascular systems responded to nerve impulses differently.”
In young women, the team suspects that reproductive hormones, known to be protective against cardiovascular disease, may prevent the blood vessels from becoming constricted when nerve traffic is high.
“We've known for many years that men and women are different in terms of blood pressure regulation,” says Dr. Charkoudian, who is working on the project. “We know that young women have a lower risk of developing hypertension (high blood pressure) compared to young men. In this study, we focused on the importance of the sympathetic nervous system and its control of blood vessels as determinants of long-term blood pressure. Our data suggest that one of the ways women are ‘protected’ is by an influence of female hormones to alter this nerve-blood vessel interaction.”

The Joyner lab recruits a wide range of people for their studies including the occasional elite or master athlete, active and sedentary people, and those with medical conditions such as hypertension, heart failure, diseases of the autonomic nervous system and, especially people who have problems with blood pressure regulation.

Friday 23 September 2011

Apple-picking your way to active health!

It's apple-picking season, and if you're lucky enough to live in a region with orchards, then there are so many good reasons to get out amongst the trees. Aside from the exercise and fresh air, experts now agree on the wide-ranging health benefits of this unassuming fruit.

With more than 7,500 varieties worldwide, apples pack a powerful nutritional punch, containing vitamins A and C, potassium and fiber. Apples are free of saturated and trans fats, and a medium-to-large-sized portion has only about 100 calories.

Research also suggests that apples may reduce the risk of certain cancers, specifically colon and prostate. Apples may protect the lungs of adults by reducing the risk of asthma and lung cancer. The fiber content is helpful for optimal functioning of the gastrointestinal tract.

And don't forget to eat the peel: it's ripe with pectin, a type of fiber, and polyphenols, powerful antioxidants, which can reduce cholesterol and LDL (bad) cholesterol levels. A study at Florida State University in Tallahassee published last spring confirmed these heart-healthy findings. There is also some evidence that eating apples helps regulate blood sugar and helps control your appetite.

Last year, the Iowa Women's Health Study reported that, among the 34,000-plus women it's been tracking for nearly 20 years, apples were associated with a lower risk of death from both coronary heart disease and cardiovascular disease. Some years earlier, Finnish researchers studying dietary data collected over 28 years from 9,208 men and women found that frequent apple eaters had the lowest risk of suffering strokes compared with non-apple eaters.

Experts attribute the heart-healthy benefits to antioxidant compounds found in apples, which help prevent LDL cholesterol from oxidizing and inhibit inflammation. Plus, the soluble fiber in apples has also been shown to lower cholesterol levels. On top of that, Eating an apple before you work out may boost your exercise endurance. Apples deliver an antioxidant called quercetin, which aids endurance by making oxygen more available to the lungs. One study showed that quercetin - when taken in supplement form - helped people bike longer

Apples are considered a "slow food" because you must take the time to chew them, giving your body time to feel full before you eat too much. The natural sweeteners in apples enter the bloodstream more slowly, keeping your blood sugar and insulin levels steady so that you feel full longer.  Another study found that apples might enhance your memory and keep your brain healthy as you age.

So make the most of the next few weeks - it's peak apple-picking time and this is a great way to sneak a little extra activity into your weekend!

Monday 12 September 2011

Better food choices start at home


Can a cozy dining table and nice music prompt people to reach for the greens and go light on dessert? 

So suggests a new study probing why people tend to eat more-nutritious meals at home than away from home. The findings, based on data from 160 women who reported their emotional states before and after meals, add to mounting evidence that psychological factors may help override humans’ wired-in preference for high-fat, sugary foods.

“Over the course of evolution in a world of food scarcity, humans and animals alike have been biologically programmed to elicit more powerful food reward responses to high-caloric foods” than to less-fattening fare, the study notes. Given those hard-wired urges, it may not be enough to understand that broccoli is better for the waistline than French fries. Home is known to be where people feel most content, and the positive emotions often associated with home-cooked meals may be part of the recipe for a healthy diet, the researchers indicate.

The findings, published in the July issue of the American Journal of Clinical Nutrition, suggest that people who are in a good mood at home tend to prepare healthier meals – and feel more emotionally rewarded after eating them. That cycle of positive reinforcement was more pronounced at home than elsewhere.
  
The report, by Prof. Ji Lu of Nova Scotia Agricultural College, Catherine Huet, and Prof.. Laurette Dubé of McGill University’s Desautels Faculty of Management, concludes that “the home is a privileged environment that nurtures healthy eating and in which healthier food choices trigger and are triggered by more positive emotions.”

This pattern may help explain why people make better choices at home than when eating out, says Prof. Dubé, senior author of the study and scientific director of the McGill World Platform for Health and Economic Convergence.

One limitation of the study is that all 160 participants were non-obese, white English-speaking women. Samples that vary in sex and culture, as well as samples that include children and obese populations, will be needed to demonstrate the extent to which the results can be generalized, the authors caution.

Even so, the findings provide insights that point toward novel strategies to encourage healthy eating, they conclude. Such strategies could rely on factors such as “interpersonal communications, home design and atmospheric cues” including “music, dining landscape, and kitchen equipment, which have all been found to induce positive emotions in both everyday and laboratory contexts.”