Taking the Plunge? Beware: Exercise in Cold Water May Increase Appetite
Lesley White, a researcher at the University of Florida, found in a study that exercising in cold, instead of warm, water may increase people's appetites so that they eat more later, making it harder for them to lose extra pounds. This may be the reason why aquatic exercise is often less successful than jogging or cycling (for the same time) for people who want to lose weight.
Water exercise is suggested for people who are overweight because the buoyancy given by the water makes exercising easier, especially if they have joint or balance problems or coordination difficulties. Body temperature seems to have some influence over postexercise appetite, and this may be why plunges into cold water make us want to eat more.
Source: Int J Sport Nutr Exerc Metab.
Do Young People in Britain Get Enough Sunlight?
Some adolescents in Britain do not get enough sunlight to satisfy the body's requirement for vitamin D throughout the year, says an editorial in the BMJ. But this does not give cause to abandon skin cancer awareness campaigns.
Fear of skin cancer in the United Kingdom may have led to children spending less time exposed to sunlight, reducing the opportunities for the production of vitamin D in the skin, and resulting in poor bone health. Evidence also shows that sunlight exposure and the resulting synthesis of vitamin D might reduce the risk of certain cancers and, perhaps, multiple sclerosis.
In response, there have been calls for current skin cancer awareness campaigns in the United Kingdom to be abandoned. Adequate sun exposure is not easily defined, but it is thought that a weekly dose of 1 MED (minimal erythema dose-the exposure necessary to result in a just perceptible reddening of the skin) to the face, hands, and arms in the spring, summer, and autumn is more than adequate to satisfy the body's requirement for vitamin D throughout the year.
But such evidence is not enough to justify abandoning current awareness campaigns about skin cancer, which are aimed primarily at avoiding excessive exposure.
Source: BMJ. 2005;331:3-4.
Dietary Salt and Calcium: Racial Differences
Purdue University scientists led by Connie Weaver, PhD, found that African American and Caucasian adolescent girls handle sodium and calcium differently. This may help explain why the races have different rates of hypertension and osteoporosis. Caucasian girls lose more calcium in their urine than African American girls, but both races lose calcium at an accelerated rate when they consume a high-salt diet.
One of 4 Caucasians will be diagnosed with osteoporosis, a bone-loss disease that costs Americans $14 billion a year in medical expenses. The disease strikes only 1 of 10 African Americans, which is less than the rates in whites. On the other hand, African Americans are more susceptible to hypertension, Dr Weaver said.
Dr Weaver's data come from Purdue's Camp Calcium, a summer camp, funded by the National Institutes of Health, which investigates calcium metabolism in adolescent girls and boys.
Thirty-five campers, 22 African American and 13 Caucasians, all 10 to 15 years old, participated in two 20-day summer camp sessions that were 2 weeks apart. While in the camp, the girls ate a controlled diet that provided certain amounts of calcium and other nutrients. During the first session, half of the girls received a low-sodium diet and half received a high-sodium diet. The diet was reversed during the second session.
Dr Weaver found that adolescent girls need to have the equivalent of 4 cups of milk a day to take full advantage of the pubertal growth spurt. Adolescence is a time when their bodies can develop peak bone mass and keep 25% of the net calcium they consume, but by the time they are young women, it drops to 5%. Additionally, Weaver's group discovered that Caucasian adolescent girls lose more calcium through their urine than African American girls, resulting in lower bone density.
"Salt intake affects how the body uses calcium at a critical time of bone development in young girls, but in whites more than in blacks," Weaver said. "This is something that should be easy to monitor in order not only to ensure healthy bones in adults, but also to reduce health-care costs of our aging populations."
Source: Am J Clin Nutr.
Exercise Can Combat High C-Reactive Protein Levels
Inflammation anywhere in the body increases levels of a substance called C-reactive protein (CRP) in the blood. Many scientists suspect that slightly elevated CRP levels are a hint that low-level inflammation may be fueling atherosclerosis and raising the risk for a heart attack, reports an article in the July issue of Harvard Men's Health Watch.
According to the article, it is not certain that lowering CRP will reduce heart attack risk, but there are clues that it might. Statin therapy, moderate alcohol consumption, and low-dose aspirin are all associated with a reduced risk of coronary artery disease, and studies find that they also lower CRP levels. And this year, 2 major studies found that CRP levels predict risk even when cholesterol-lowering statins bring LDL cholesterol to very low levels.
Research suggests that exercise can also reduce CRP levels. In one study, moderate exercisers were 15% less likely than couch potatoes to have elevated CRP levels, and those who exercised vigorously were 47% less likely to have a high CRP level. As of 2005, 12 additional studies have reported that people who exercise regularly have lower CRP levels than their sedentary counterparts.
Findings about CRP represent just one of many recent advances in understanding coronary artery disease. Regular exercise can reduce a man's risk for a host of ills, including cardiovascular disease, diabetes, an enlarged prostate, and erectile dysfunction.
Source: Harvard Men's Health Watch.
Americans Low on Zinc
According to Consumer Reports, a US Department of Agriculture survey found that 73% of Americans do not get enough zinc, a mineral important for immune-system functioning, wound healing, and overall health. To ensure that you are getting the recommended 15 mg/d, include zinc-rich foods in your diet: fortified breakfast cereals, buckwheat, beef, lamb, crab, and oysters. To avoid nutrient imbalances, make sure that your total intake from foods and supplements does not exceed 40 mg a day. And dietary supplements with zinc should not exceed daily value levels.
Source: Consum Rep. July 2005.
Top 10 Summer Fitness Activities for Families
If we can take pleasure in physical activities with those we love, it is much more likely we will have fun and stick to it on a regular basis. The key is to choose activities that everyone will enjoy so the whole family spends time together. The American Council on Exercise shares the following activities that can make summer fun and healthy. Here are the top outdoor activities for summer fun with your family.
1. Walking: Take the whole family on a walk around the neighborhood or a local destination. Try walking to the park or your community pool if it is not too far away instead of driving.
2. Swimming: An effective workout for the entire body, swimming is an appropriate activity for a variety of fitness levels.
3. Bicycling: On the street or on the trails, bicycling is a terrific activity for all ages. Do not forget that everyone needs to wear a helmet.
4. Canoeing or kayaking: If you have access to water, canoeing or kayaking can be a blast and a great upper-body workout. Of course, life jackets are a must for all ages.
5. In-line skating: Shoes on wheels may keep your family moving at the same speed and make getting places a bit more fun. Do not forget to wear protective gear like wrist guards and helmets to prevent injuries.
6. Beach games: Build a sandcastle or play in the surf. Running around in the sand all day lets you get in your exercise while you are having fun.
7. Team sports: Games such as doubles tennis or 2-on-2 basketball are great for smaller groups while touch football, softball, and volleyball are fun family activities that can accommodate a larger group.
8. Park games: Toss around a football or Frisbee in a safe and wide-open space or take advantage of the park's facilities such as playgrounds and obstacle courses.
9. Hiking: Pack a healthy lunch and head out into the great outdoors for a hike. Hiking is a great workout and you also have the opportunity to take advantage of the beauty of nature.
10. Lawn games: Set up croquet or badminton in your backyard or turn on the sprinklers for an instant water park on a hot summer day.
Source: American Council on Exercise.