Friday, February 26, 2010

Intense Exercisers Have Longer Telomeres

Researchers in Homburg, Germany showed that 50-year-old men who ran more than 50 miles per week at a fast pace had telomeres (chromosome caps) that were almost the same length as those of 20-year-old runners on the German National Team, and more than 40 percent longer than those or inactive men of the same age (Circulation, December 2009). This is astounding because shortened telomeres represent aging.

The active ends of the genetic material (chromosomes) in cells are covered with a layer of proteins called telomeres. If they weren't, the exposed ends of the genetic material would stick to anything nearby and the cells would die. However, each time a cell divides to make two cells, a little bit of the telomere is removed. Eventually the telomere is gone, the ends of genetic material stick together and the cell can no longer divide so it dies without replacing itself. Obviously, the longer the telomeres, the longer it takes for the telomeres to be used up and the longer a cell lives.

Two years ago, researchers at King's College in London reported in 2,401 sets of twins that those who exercised regularly have telomeres that are longer than those of their twin couch potatoes (Archives of Internal Medicine, January 28, 2008). Other studies show that people who exercise regularly live an average of 12 years longer than non-exercisers (British Journal of Sports Medicine, March 2008). Most middle-aged and older athletes look significantly younger than non-exercisers of the same age.

Following the training methods of competitive athletes allows fit older people to run, cycle and do other sports at close to the level of much younger athletes. Recent studies show that intense exercise may also slow the effects of aging on their cells as well as their hearts and muscles. However, intense exercise can cause heart attacks in people with blocked arteries, so check with your doctor before you increase the intensity of your exercise program. More

Sunday, February 21, 2010

Weight Lifting Rules for Middle Age and Beyond

Many middle-aged and older people have started to lift weights, since extensive data show that lack of muscles increases risk for diabetes, heart attacks and premature death (British Medical Journal, September 2009; Journal of Physiology, September 2009). However, within the first few weeks of their new weight-lifting programs, most get injured and quit.

Usually they are injured because they try to train like younger men: by picking the heaviest weight that they can lift ten times in a row, resting and repeating that set two more times. Then they feel sore for the next few days and when the soreness lessens, they lift heavy weights again, usually two or three times a week. This type of training almost always injures older novice weight lifters and ends their training program.

The safest way for most older men and women to gain strength and increase muscle size is to join a gym and try to use 15 to 20 Nautilus-type machines every day. On each machine they should pick the weight that they can lift and lower 10 times in a row comfortably, without straining or damaging their muscles (which would make their muscles feel sore on the next day). If they feel the least bit sore, they should take a day or days off until the soreness is gone. As they become stronger and the weights feel very easy for them, they should try to lift 15 times in a row, then 20 and perhaps 25 times. They should always do just one set. Only when they can lift that weight at least 20 times in a row and not feel sore the next morning, should they increase the resistance by going to the next heavier weight.

The key to this program is to avoid injuring their muscles by lifting weights in a single set and increasing the number of repetitions gradually so they do not cause next-day muscle soreness. They should not increase the weight (resistance) until they can lift a set of at least 20 daily and not feel sore the next day.

Before any older or out-of-shape person starts an exercise program, he or she should check with a physician to rule out serious problems that might be aggravated by weight lifting.

This program is for beginners and is intended to prevent injuries that plague older people when they first try to lift weights. It will not build very large muscles. It will, however, increase strength and provide the other benefits of a weight training program. After many months (injury-free) on this program, if a person wishes to build larger muscles, he or she can transition to a more traditional weight training program

Saturday, February 06, 2010

Eggs Do Not Cause Heart Attacks

Eggs have not been shown to increase risk for heart attacks, according to an an extensive review of the world's scientific literature in the American Journal of Lifestyle Medicine (July-August 2009). For example, the Physician's Health Study followed doctors for 20 years and showed no association between eating eggs and heart attacks or strokes. However, the doctors who ate lots of eggs did die earlier than those who avoided eggs, possibly because they also ate more bacon, sausage and butter.

The concern that eating eggs can cause heart attacks comes from the fact that eggs are one of the most concentrated sources of dietary cholesterol. Indeed, adding one egg per day can raise blood cholesterol levels by one to three percent. However, virtually all large population studies show no association between eating eggs and blood cholesterol levels. In fact, the Framingham Heart Study and NHANES study found that high-egg eaters had lower cholesterol levels than very-low eggs eaters.
Journal references on all of the studies mentioned in this article

Current opinion is that some people have their blood cholesterol levels raised by eating eggs, while others do not. Indeed, 70 percent of Americans will not have their cholesterol levels affected by eating eggs. Furthermore, those who did have their cholesterol levels raised by eating eggs, had rises in both their good HDL and bad LDL cholesterol levels and also had higher large particle cholesterol that prevents heart attacks. Both rises in the good HDL cholesterol and cholesterol particle size help to prevent heart attacks.

I have started to eat eggs again after avoiding them for more than forty years. I continue to load my plate with lots of vegetables and fruits, and eat reasonable amounts of fish. I avoid all meat from mammals. I avoid all refined carbohydrates except during and immediately after exercise. My recommended diet

Wednesday, February 03, 2010

Muscle Growth Hindered by Obesity or High-Fat Diet

A study from the University of California, Davis shows that a high-fat diet prevents exercising mice from enlarging their muscles (Journal of Physiology, December 2010). The mice received either a low fat, high carbohydrate diet or a high fat, low carbohydrate diet for 14 weeks. Each group was divided into those who performed progressive resistance exercises with their plantaris muscles or those that did not do this exercise. Those who exercised on the low fat, high-carbohydrate diet had substantially larger muscles than those who exercised on the high-fat diet. Chemical analysis of their muscles showed that the high fat diet group had lower levels of polysomes (Akt and S6K1) necessary for making protein.

If this study can be applied to humans, it will mean that not only does a high-saturated-fat diet make you fatter, it also keeps you from enlarging your muscles. We know that both full fat cells and eating large amounts of saturated fats (the dominant fat in meat) turns on your immunity to cause inflammation that can prevent the body from making protein necessary for enlarging muscles. (Journal of Nutrition, January 2009). A high saturated-fat diet also blocks insulin receptors and thus prevents your body from responding to insulin, which is necessary for muscles to heal from intense workouts. Insulin drives amino acids, the protein building blocks, into muscles to help them heal faster. Anything that blocks muscles' ability to respond to insulin will decrease amino acid entry into muscles and thus delay healing so you can't recover as fast for your next workout.
Further journal references and recommendations