Wednesday, October 31, 2007

Blood Sugar Levels Affected by Activity

How foods affect blood-sugar levels varies from person to person and from one time to another in a single individual. For example, if you eat a jelly donut in the evening, your blood sugar may rise well over 200 (it should never be higher than 160). If you eat the jelly donut when you have been riding your bike for an hour, your blood sugar level may not rise at all.

Researchers at University Medical Center in Utrecht, the Netherlands showed that eating sugar and flour markedly increases risk for heart attacks in middle-aged women. Being overweight increased the risk even more. More than 15,000 healthy Dutch women, ages 49-70, were followed for nine years. They suffered 556 cases of coronary heart disease and 243 strokes. The ones most likely to be afflicted were overweight women who ate a diet high in foods that cause a high rise in blood sugar. Journal reference

The only places that you can store sugar in your body are your liver and muscles. If you eat lots of sugar or flour when your muscles are full of sugar, sugar goes from your intestines, into your bloodstream and then can spike to high levels. However, during or after prolonged exercise, sugar goes from your intestines into your bloodstream and then directly into your muscles, so it does not spike. For diabetics or overweight people, the safest time to eat foods that cause a high rise in blood sugar is while they are exercising. More on glycemic load of foods; refined carbohydrates; preventing diabetes

Monday, October 29, 2007

Longer Lower Legs Benefit Runners and Walkers

People who have longer lower leg lengths (the distance from knee to ankle) will usually have greater endurance during running or walking than those with shorter lower leg lengths. In a study reported in the Journal of Human Evolution, researchers at the University of Wisconsin showed that people with longer lower legs use less energy when they run.

In a previous paper in the same journal, these authors showed that people with longer lower legs are better able to prevent heat build-up, which slows you down and makes you tired. When you exercise, almost 80 percent of the energy that you use to power your muscles is lost as heat. So the harder you exercise, the more heat you produce and the harder your heart has to work to get rid of the extra heat. You prevent heat buildup by your heart pumping hot blood from your muscles to the skin where it is cooled by sweat and conduction and radiation. Journal references

People with longer lower limbs use up less oxygen and produce less carbon dioxide for the same energy expenditure. Therefore they are more efficient and can go further because their bodies require less oxygen.

You can't change the length of your lower legs, but you can increase running efficiency

Friday, October 26, 2007

Protein: How Much Do You Need?

The Recommended Allowance for protein for most people is about 70 grams per day. Many types of foods contain protein, and it is easy to meet your protein requirements with a typical varied diet. For example, you would meet your daily requirement for protein if you ate two of cups each of beans and whole grains such as barley, brown rice or oatmeal, three ounces of tuna, and two glasses of milk or a vegetarian milk substitute. If you are not sure whether you eat enough protein, keep track by checking the labels of the foods you eat for a few days. You will probably find that you get plenty of protein without any special effort.

Protein is made up of protein building blocks called amino acids. Your stomach acids and enzymes in the stomach and intestines break down proteins into these building blocks, which pass from the intestine into the bloodstream. If your body needs to build protein, your liver combines amino acids to form body proteins. If you don't need all of the protein you have eaten, it is broken down into organic acids and ammonia, which can be used for energy or be converted to fat. If you take in more protein than you need on any given day, it will be stored as fat because you cannot store protein in your body.

Competitive athletes or heavy exercisers need more protein to repair muscles after workouts. Muscles heal from a hard workout when amino acids and other nutrients travel from your bloodstream into the muscles. Eating any foods, particularly those that are good sources of protein, immediately after a workout helps muscles heal faster. More

Wednesday, October 24, 2007

Restaurant Meals Can Be Healthful

Everyone can enjoy an occasional meal in a restaurant without worrying about the consequences. But if you have to eat in restaurants several times a week, you need to devise ways to make healthful choices and avoid the temptation to over-eat. If you are trying to control weight, diabetes, cholesterol or high blood pressure, you must find ways to meet your special requirements.

First, choose restaurants that gives you a fighting chance. Find a restaurant with a good salad bar and load up on fresh vegetables. Order broiled fish for your entree. Ask to have it prepared with lemon juice instead of butter. Have steamed vegetables as an accompaniment, without added butter, and fresh fruit or fruit ice for dessert.

Asian restaurants often have a wide array of tasty dishes with lots of vegetables. Thai and Vietnamese restaurants and Mongolian grills are good choices if you stick to the vegetarian and seafood entrees. Go easy on the white rice.

Your chances of finding whole grains in a restaurant are slim to none, but if you travel a lot, you might want to pack or shop for your own cereal to eat in your hotel. Large cities and college towns often have vegetarian restaurants that offer varied, flavorful meals made with vegetables, beans and sometimes even whole grains. Whatever you order, watch out for the huge portions that many restaurants serve. Divide it up at the beginning of the meal and save some for the next day's lunch, share with a friend, or just leave it.

List of national chain restaurants that offer good to excellent salad bars and some other healthier choices for people on the go

Tuesday, October 23, 2007

Walking to Lose Weight: Miles Less Important than Intensity

For exercise to help you control weight, you must exercise fairly intensely or else you need to exercise for many hours, and most people do not have the time to exercise for three or four hours or more every day. A study from the University of Massachusetts in Boston shows that middle-aged women who exercise at very low intensity are fatter and gain weight far more easily than women who exercise more intensely. Journal reference

This is what you would expect. When you exercise intensely enough to raise a sweat, you can increase your metabolism and continue to burn extra calories for several hours after you stop exercising. When you exercise at very low intensity, you do not increase your metabolism and you have to exercise for a very long time to burn a significant number of calories. If walking is your exercise choice for weight loss, walk vigorously enough to sweat and breathe hard.

People who want to use exercise to control weight should first check with their doctors. They should pick an activity that they can do regularly and try to do it every day. On some days, they should try to exercise more intensely, feel sore on the next day, go at low intensity for as many day as it takes for the soreness to go away and then exercise intensely again. People are more likely to stick with an exercise program if they do it with a spouse, a good friend or a personal trainer, or in a social setting such as a class or club. More

Sunday, October 21, 2007

Sugar Helps You Exercise Longer

Bicycle racers in long events such as the Tour de France take sugar supplements while they ride to increase their endurance. If you plan to exercise for more than two hours, you can help yourself last longer by taking a source of sugar after 30 minutes and several times more throughout your event.

When you exercise, you convert food to energy for your muscles by stripping off electrons and hydrogen from the foodstuffs. This process manufactures a chemical called ATP that provides energy that does not require oxygen. A study from the University of Waterloo in Ontario, Canada shows that taking sugar during prolonged exercise raises levels of ATP. At exhaustion, ATP levels were at the same low levels in both the group taking sugar and those taking artificial sweeteners. However, prior to exhaustion, those taking sugar had higher levels to help them exercise longer. Journal reference

You do not get this benefit from sugar eaten before you exercise because high blood sugar levels that result will cause your pancreas to release large amounts of insulin. The extra insulin will deplete the sugar stored in your muscles faster and tire you earlier. Thus if you want to exercise intensely for more than a couple of hours, you need to eat or drink a source of carbohydrates at frequent intervals during your activity.

Friday, October 19, 2007

Build Aerobic Capacity by Strengthening Leg Muscles

Aerobic capacity is a measure of your ability to use oxygen to do work. If your body can process more oxygen than that of another person, usually you will be able to run faster, walk or work longer, and have more energy than that person.

The loss of aerobic capacity with aging explains why older people cannot compete effectively against younger ones in endurance events. The good news is that a regular exercise program can help you compensate for this loss by strengthening skeletal muscles and increasing your maximum heart rate.

Tasks that you did without effort when you were younger can become major ordeals that leave you exhausted when you are older. It takes more effort and time to walk up stairs, mow the lawn, fix a faucet or wash the dishes. Dr. Jerome Fleg, a cardiologist at the National Heart, Lung, and Blood Institute, tested 800 men and women over several years and found that their ability to sustain exercise decreased rapidly as they aged. The older they became the faster they lost aerobic capacity.
The men and women lost three to six percent per decade in their 20's and 30's, and 20 percent per decade in their 70's. The men lost aerobic capacity faster than the women. The men lost 8.3 percent of aerobic capacity in their 40's and 23 percent per decade in their 70's. This study was done with people who were healthy enough for vigorous exercise on a treadmill that measured their exercise capacity. People who have had heart attacks, strokes, diabetes or other wasting diseases would lose aerobic capacity much faster than healthy people. Journal reference

A regular exercise program can increase exercise capacity by up to 25 percent, which would give the older participants the same exercise capacity as you would expect in people who are twenty years younger.

With vigorous exercise, you develop stronger skeletal muscles. When you contract your leg muscles, they squeeze against the veins in your legs and pump blood toward your heart. When your leg muscles relax, the veins dilate and fill with blood. This alternate contacting and relaxing pumps extra blood toward your heart. The extra blood returned to the heart stretches and strengthens the heart muscle, causing it to beat faster and with more force. So strengthening your leg muscles increases your maximum heart rate, even as you age.

Thursday, October 18, 2007

How Vitamin D Helps to Prevent Cancer

Many recent reports show that vitamin D is far more than just a hormone that strengthens bones. It is necessary for maintaining a healthy immune system. Every day, your body produces millions of cancer cells, and your immunity is supposed to search out and destroy these cells. However, when you lack vitamin D, your immunity is less able to destroy cancer cells. A study from Creighton University in Omaha, Nebraska, showed that women had a 77 percent lower rate of cancer in the second through fourth years of taking calcium and vitamin D pills than women taking placebos. Journal reference

The only really rich food source of vitamin D is fatty fish. Very few people are able to meet their needs for vitamin D from the foods that they eat and have to depend on sunlight to cause their skins to manufacture it. But concern about skin cancer has encouraged many people to avoid direct exposure to sunlight. Vitamin D deficiency is common in northen latitudes, particularly in people who have dark skin that blocks ultraviolet light. It is also common in overweight people because fat cells hold on to vitamin D and prevent it from being utilized. People who are at risk for vitamin D deficiency can ask their doctors to order a blood test to measure vitamin D levels. If low, they may need more sunlight, more fatty fish or vitamin D supplements.

Wednesday, October 17, 2007

High Resting Heart Rate: Common Causes

If your resting heart rate is greater than 70, check with your doctor to see if your thyroid is overactive, you are anemic, or you have an infection, hidden tumor, a weak heart or other cause of a rapid heart rate. Having a resting heart rate greater than 70 increases your chances of suffering a heart attack. Journal reference

At this time, there is not enough solid data to show that taking drugs to slow heart rate, by itself, will help to prevent heart disease when no cause is found. However, those with chest pain during exercise or blocked blood flow to the heart do benefit from drugs to slow heart rate. Several ongoing studies are trying to determine if all people with heart rates over 80 should take drugs to slow heart rate. Drugs that can be used to slow heart rate and prevent heart attacks include beta blockers, ACE inhibitors, angiotensin receptor blockers, statins or aspirin.

Your "Recovery Heart Rate" is likely to be even more important. Recovery Heart Rate is a measure of fitness and a slow recovery from exercise means that you are out of shape. This test can cause irregular heart beats in people with damaged hearts, so check with your physician before you try it.

To measure recovery heart rate, you exercise on a treadmill (or any other activity) until you are breathing hard, record your heart rate, and hold that pace for at least a minute. Then stop, and measure your pulse rate exactly one minute after stopping. If your heart does not slow down at least thirty beats in the first minute, you are in poor shape and at increased risk for a heart attack. If your heart rate slows down more than fifty beats in the first minute, you are in excellent shape.

You can also use the recovery heart rate to measure your improvement as you get into shape. More

Tuesday, October 16, 2007

Interval Training to Improve Performance in Sports

The faster an athlete moves in training, the faster he or she will be able to move during competition. So athletes use a training technique called interval training in which they run, cycle, skate, ski or swim very fast for a short time. When they become severely short of breath, they slow down until they recover, and then move very fast again. Researchers at Ithaca College showed that athletes can gain as much by doing this type of intense interval training on consecutive days as on alternate days (Medicine & Science in Sports & Exercise, September 2007).

Interval training causes considerable muscle damage, so it usually leaves athletes sore the next day. Most trainers recommend exercising at a slower pace until the soreness disappears. That is why athletes usually follow each intense day with one or more easy days. However, many competitions require an athlete to exercise flat out for several consecutive days. He may have to compete in multiple preliminary heats over several consecutive days to reach the finals.

In this study, the researchers asked cyclists to perform intense interval on either consecutive days or alternate days. Their improvement in time trials was the same. However, this study did not measure injury rates or risk of overtraining. Most athletes will suffer fewer injuries if they take a hard workout on one day and then go more slowly for as many days as it takes for muscle soreness to go away. More

Monday, October 15, 2007

Bicycling Tips for Blog Action Day

For Blog Action Day, here are some tips for better bicycling. You'll feel virtuous every time you ride your bicycle instead of driving your car!

All cyclists should learn to pedal at a fast cadence, whether you are an experienced racer or a novice recreational rider. Muscle fatigue and damage are caused by excess pressure on the pedals, not by how fast you pedal. Pedaling at a faster cadence with less pressure allows you to pedal longer and harder. However, several researchers have expressed concern that pedaling very fast could decrease blood flow to muscles and thus decrease athletic performance. A study from Kansas State University shows that pedaling fast does not decrease a muscle's flow of blood or ability to extract oxygen from the blood. Once again athletes and coaches find new training and competing methods and years later, scientists tell them that they are correct.

After you have been riding regularly for a time, try to spin your pedals 80 times a minute. In the beginning, you will put so little pressure on your pedals that you will ride very slowly. However, after several weeks of pedaling at a cadence of 80, you will become more comfortable and be able to move fairly well at this pace. As you become stronger, you can maintain this high cadence while using higher gears and pressing on the pedals with more force, so you will be able to ride faster and longer. Journal reference

How to pedal: You should pedal with the ball of your foot, not your arch. The ankle is the fulcrum for the force you generate with your feet. The ball of your foot is further away from the ankle than your arch so you generate far more force with the ball of your foot.

As you straighten your knee, pedal at a 45 degree angle down and forward for the greatest force. Bicycle shoes have cleats that attach to the pedals to keep the ball of your foot over the pedal, where you generate the most force. Don't wear soft-soled shoes that allow the pedals to press against your feet, which can cause pain. Experienced riders know that you should not bend your foot up when you pedal up because it wastes energy and tires you earlier.

My most important tip: get a comfortable bike seat.

Thursday, October 11, 2007

Ski Better By Preparing Now

If you love to ski, it's time to think about getting ready. The best way to train for skiing is to ski, but snow isn't always available. To prepare for a ski trip, you need to strengthen both your heart muscles and your skeletal muscles. You can strengthen your heart for skiing with any exercise that will raise your heart rate for at least 10 minutes, three times a week. However, to prepare your muscles for skiing, you have to use activities that use your upper legs, such as skating or riding a bicycle. The average bicycle rider is far better prepared for skiing than the average runner. Many joggers who can easily run ten miles find that they can't ski very long because their upper leg muscles tire and hurt after just a few minutes of skiing.

You drive yourself forward in skiing with the muscles in your upper legs. Running stresses primarily the muscles in your lower legs. It does not strengthen the muscles in the upper legs enough to allow the average person to ski for any length of time. Running stresses your upper leg muscles only when you use them to lift you up when you run hard up hills. Since you ski by bouncing up and down on your knees and shushing forward from your hips, the best sports to prepare for skiing are those that stress primarily your thigh and upper leg muscles. You can use the popular indoor exercise machines that mimic cross-country skiing motions, or ski on dry roads with roller-skis. In-line skating or cycling are good choices for outdoor preparation, particularly if you climb lots of hills. Add a weight training program to strengthen your upper body and arms as well as your legs, and you’ll be ready for the snow.

Tuesday, October 09, 2007

Sorbitol: Poison in Your Body, OK in Foods

When blood sugar levels rise too high, sugar sticks to the surface membranes of cells. The sugar, glucose, is converted into another sugar, fructose, and eventually to sorbitol, which destroys the cells. This cell damage leads to heart attacks, strokes, blindness, deafness, kidney damage and the other harmful effects of diabetes.

The same chemical is harmless when it is used in foods because you do not absorb it. Sugar alcohols such as sorbitol, mannitol or xylitol have almost the same chemical structures as carbohydrates, but they have an alcohol end on one side. This prevents them from being absorbed from your intestines, so they can be used to sweeten food without contributing any calories. The sugar alcohols pass undigested to your colon where they are fermented by bacteria, so large amounts can cause gas and diarrhea. That's why sorbitol is used only in foods such as hard candy or gum, where portion sizes are very small. How to keep blood sugar levels from rising too high; how to recognize pre-diabetes

Monday, October 08, 2007

Muscles Can Be Strengthened at Any Age

You are never too old to enlarge and strengthen your muscles. A study from Copenhagen, Denmark shows that just 12 weeks of lifting weights significantly strengthened the muscles of men 85 to 97 years of age (Scandinavian Journal of Medicine & Science in Sports, August 2007). After 12 weeks of training, the cross sectional circumference of their quad muscles in the front of their upper legs increased by 10 percent, and muscle strength increased by 35 to 50 percent. Furthermore, the muscle fibers that are used for strength and speed increased significantly.

Frailty in old age is caused by lack of exercise, not just by growing old. With aging, you lose nerves. Each nerve is attached to a single muscle fiber, so as you lose muscle fibers you become weaker. Older people who exercise against resistance can enlarge their muscle fibers. This counteracts the effects of losing fibers and they can retain a significant amount of strength.

People with weak hearts can suffer heart damage with vigorous exercise. Before an older person starts an exercise program, it may be wise to check with a doctor to make sure that the heart is sound. The most dependable heart test is a thallium stress test. Then engage a personal trainer to teach the person how to exercise on a series of individual weight lifting machines that stress different muscle groups. Usually the recommended program involves going to each machine and lifting and lowering the weight on that machine in a single set of three to ten repetitions. Most people can do this three or more times a week. Fitness newsletter

Tuesday, October 02, 2007

Caffeine, Exercise Help to Prevent Skin Cancer

High doses of ultraviolet light damage the DNA in skin cells. Normally, damaged cells commit suicide by a process called apoptosis, so that they do not become cancerous. However, damaged cells that do not undergo apoptosis live to become cancerous. A report from Rutgers University showed that exercise and caffeine help to prevent skin cancer. Researchers divided mice into four groups: 1) inactivity, 2) exercise, 3) caffeine and 4) exercise and caffeine. Then all of the mice were exposed to high doses of ultraviolet B light that damaged their skin cells. Caffeine caused a 95 percent increase in apoptosis, exercise caused a 120 percent increase, and those who both exercised and took caffeine had a 400 percent increase in apoptosis.

Cells in your body have multiple small areas called mitochondria that turn food into energy by knocking hydrogen and electrons from carbohydrates, fats, and proteins. The freed electrons can attach to oxygen to form reactive oxygen species (free radicals) that stick to the DNA of cells to damage them and cause cancer. Exercise teaches your mitochondria to turn food into energy with far fewer free electrons, so there are fewer free radicals to damage cells. Caffeine markedly increases an animal's ability to exercise for longer periods of time. Journal reference

Monday, October 01, 2007

Tapering for Athletes and Ordinary Exercisers

Tapering refers to the period just before a major race or game, when an athlete reduces workload to be in peak shape on the day of the competition. Ordinary exercisers can apply this training principle when they plan to enter a local race or charity event.

Top athletes must spend a tremendous amount of time training to be able to compete successfully. Their huge volume of work leaves them near exhaustion and before major competitions, they have to find the best way to reduce fatigue while retaining fitness. Many studies have been done to help athletes and coaches decide on the best strategy. Researchers at the University of Montreal compiled the results of 27 scientifically acceptable studies. They concluded that the best duration of tapering is two weeks, the optimum training volume reduction is by 40 to 60 percent, and the intensity of workouts should be maintained (Medicine & Science in Sports & Exercise, August 2007).

Training load during taper: Almost all of the studies agree that athletes should reduce the amount of work they do. While each athlete must decide on his optimal reduction, many bicycle racers drop from up to 400 miles a week down to fewer than 200, and many runners drop from above 100 miles to fewer than 40.

Duration of taper: A tapering period of eight to fourteen days appears to optimize performance in which an athlete can lose his fatigue and still maintain his ability to compete at high intensity.

Intensity during taper: Almost all studies show that athletes need to maintain intensity during tapering. During background training, they take workouts in which they run, skate, ski, cycle and swim very fast two or three times a week. They often continue these intense workouts during the two-week taper, stopping a few days before the competition.

While nobody really knows how tapering improves performance, most researchers believe that it increases a person's maximal ability to take in and use oxygen (VO2max). This is explained by increases of blood volume, red cell production and enzymes that utilize oxygen in the production of energy. Since fatigue interferes with coordination, tapering alleviates fatigue to improve efficiency of movement that, in turn, improves a person's ability to use oxygen for energy. More training tips