Sunday, September 27, 2009

Osteoarthritis: Treat with Exercise

A review article from the University of British Columbia in Vancouver shows that exercise does not increase the rate of knee damage in people with osteoarthritis, and usually reduces knee pain and disability (Canadian Family Physician, September 2009).

If you develop pain in your knee that was not caused by an accident or trauma, your doctor will usually check you for known causes of joint damage. If he finds no cause, he will tell you that you have osteoarthritis, which means that he doesn't know why your knee hurts. Most people with osteoarthritis (not associated with trauma) are overweight, do not exercise, and/or have weak muscles that support knee movements.

Osteoarthritis causes a higher incidence of disability than any other chronic condition. It makes exercise difficult, and not exercising increases risk for heart attacks. One in three North Americans over 60 have X ray evidence of osteoarthritis.

People with osteoarthritis should avoid contact sports, but exercise is more effective than any medication to treat this condition. The best activities include swimming and other water- based exercises, stationary cycling or cycling on the road, and muscle strengthening exercises using Nautilus machines or similar equipment at a gym. People with knee osteoarthritis should avoid sports that involve sudden shocks to the knee, such as when the foot hits the ground during running. Inactivity and overweight increase your chances of further knee damage and often lead to a joint replacement. More on arthritis

Wednesday, September 23, 2009

Preventing Loss of Muscle Strength with Aging

As you age, you lose muscle size and strength much faster than you lose endurance or coordination. Researchers at the University of Nottingham in England show that a major cause of loss of muscle is that aging prevents muscles from responding to insulin and that exercising helps to slow this loss of muscle size and strength (The American Journal of Clinical Nutrition, September 2009).

Insulin drives amino acids into muscles to help them recover from exercise and maintain their size. Researchers traced radioactive amino acids and showed that insulin drives the amino acids into muscles much more effectively in 25-year-olds than in 60-year-olds. They also showed that the blood flow in younger people's legs is much greater and supplies far more nutrients and hormones. However, three exercise sessions per week over 20 weeks markedly increased blood flow in the legs of the older subjects, enough to reverse muscle wasting.

People of all ages can use this information to help themselves become stronger. Athletes in all sports train by stressing and recovering. They take a hard workout, damage their muscles, feel sore the next morning, and then take easy workouts until the muscles heal and the soreness goes away. The athlete who can recover the fastest can do the most intense workouts and gain the most strength.

Eating a high carbohydrate-high protein meal within half an hour after finishing a workout raises insulin levels, increases amino acid absorption into muscle and hastens recovery (Journal of Applied Physiology, May 2009). The carbohydrates cause a high rise in blood sugar that causes the pancreas to release insulin. Insulin drives the protein building blocks (amino acids) in the meal into muscle cells to hasten healing from intense workouts. Muscles are extraordinarily sensitive to insulin during exercise and for up to a half hour after finishing exercise, so the fastest way to recover is to eat protein- and carbohydrate-rich foods during the last part of your workout or within half an hour after you finish.

Here's how Diana and I (ages 67 and 74) use this information on insulin sensitivity. We ride hard and fast for about 20 miles on Tuesdays, Thursdays and Saturdays. On our recovery days, we ride slowly for one to three hours. Mid-day we go to a buffet restaurant and eat a large meal with fish, shrimp, vegetables and other sources of protein and carbohydrates. After eating, we ride slowly for one or two more hours. Riding before we eat makes our muscles very sensitive to insulin. This causes insulin to drive amino acids rapidly into our muscles and help them recover faster. Riding after we eat helps us to avoid a high rise in blood sugar that damages cells. You can use either plant or animal sources of protein; both contain all of the essential amino acids necessary for cell growth.
More on principles of training

Thursday, September 17, 2009

What Causes Prostate Cancer?

We don't know what causes prostate cancer, but a study from Harvard School of Public Health shows an association between the common sexually transmitted infection, Trichomonas vaginalis, and risk of the type of prostate cancer that kills (Journal of the National Cancer Institute, September 9, 2009). Researchers analyzed blood samples collected in 1982 from 673 men who were diagnosed with prostate cancer more than ten years later. Trichomonas vaginalis infection was associated with a more than triple risk for the type of prostate cancer that kills.

Trichomonas vaginalis infects about 174 million people each year and is the most common non-viral sexually transmitted infection. Up to three-quarters of men infected with Trichomonas vaginalis may have no symptoms at all. Trichomanes can usually be cured just by having all sexual contacts take metronidazole for five to ten days.

Several other cancers are caused by bacterial infections. For example, the bacterium Helicobacter pylori is the most common cause of stomach cancer. Bacteroides fragilis, a bacterium that causes diarrhea, has been associated with colon cancer (Nature Medicine, September, 2009). Chronic infections activate your immune system to cause inflammation, which can block apoptosis to cause cancer.

More than 90 percent of prostate cancers probably should not be treated because they cause no harm. A study in the Journal of the American Medical Association (September 15, 2009) followed men with early stage prostate cancer who were cared for without surgery or radiation. Ten years later, only six percent had died from prostate cancer. The average time from diagnosis to death for untreated prostate cancer is more than 22 years. However, five percent of prostate cancers may need immediate treatment as they grow rapidly and can kill. A reliable test that tells which prostate cancers are likely to kill would save anxiety, potency and continence for a lot of men. Such a test is not available at this time. The authors of this study recommend that doctors and patients reconsider the watch and wait option. More on prostate cancer

Friday, September 11, 2009

Use Lactate Threshold instead of Maximum Heart Rate

My report on the unreliable Maximum Heart Rate formula brought many questions on how heart rate SHOULD be used for training. Competitive athletes often use a guide called lactate threshold (LT). When you exercise, your muscles require oxygen to convert food to energy. If you exercise so intensely that you cannot get enough oxygen, lactic acid accumulates in your muscles and spills over into your bloodstream. This makes your muscles more acidic which causes terrible burning, and you to become short of breath and slow down as you struggle to get more oxygen. Your lactate threshold occurs when you exercise at the highest average heart rate you can maintain for 45-60 minutes. RoadBikeRider.com offers the following guidelines for cyclists; the same principles can be used in any other endurance sport.

"A good way to find your LT is to ride a fairly flat 15-mile course at a hard pace. Use a heart monitor that averages heart rate for the distance or just check it occasionally to see where HR settles.

You'll quickly find that you can maintain a certain high HR, but if you go a few beats higher you'll start panting and be unable to control your breathing. Trial and error will reveal the highest HR you can maintain for the distance. That's your LT.

Three simple exercise zones based on your LT heart rate are sufficient. These guidelines should work for most riders:
Recovery takes place about 40 beats below LT
Endurance is built on rides about 25 beats below LT
Breakthrough training is done from 10 beats below LT to about 5 beats above LT
No heart monitor? You can do just as well by monitoring your perceived exertion. For instance, recovery rides should be so easy that you barely feel the pedals. The idea is to take a 'walk' on the bike. Hard efforts, such as intervals and climbing, should be at the limit separating steady-but-labored breathing from panting and gasping. By experimenting you'll find this LT boundary."

Whatever your sport, I recommend subscribing to RBR's free newsletter; it's full of useful information for exercisers.

Thursday, September 10, 2009

NSAIDs Interfere with Proper Training

Ibuprofen and other NSAIDs (Non Steroidal Anti-Inflammatory Drugs - Motrin, Advil, Alleve and so forth), taken before or after exercise, interfere with the benefits of training for fitness and athletic competition because they delay healing of damaged muscles (British Journal of Sports Medicine, August 2009). You train for sports by taking a hard workout that damages muscles and makes them feel sore. You then take easy, less intense workouts for as long as it takes for the soreness to go away. Only then should you take intense workouts again. Swimmers take hard and easy workouts every day, but athletes in virtually all other sports allow at least 48 hours between intense workouts.

Biopsies done the day after a hard workout show bleeding into the muscle fibers and disruption of the Z-bands that hold muscle fibers together. Injured muscles release healing prostaglandins that cause collagen to be laid down in muscle fibers to make them larger and stronger. They also cause pain. NSAIDs block the training effect by blocking healing prostaglandins, thus delaying recovery and collagen production. They prevent bones, muscles, tendon and ligaments from thickening and becoming stronger.

Athletes taking NSAIDs during competition are at increased risk for bleeding into their kidneys, and for intestinal bacteria to enter their bloodstreams (Brain, Behavior and Immunity, November 2006). An estimated 60 percent of athletes competing in triathlons and other endurance events take NSAIDs because they think that it will block the pain of competition. NSAIDs have not been shown to block the pain and fatigue of competing in athletic events that require endurance.

Ordinary aspirin delays muscle healing by blocking many of the same healing prostaglandins that are blocked by NSAIDs. Aspirin also increases risk for
bleeding if you should have an accident.

Tuesday, September 01, 2009

Your Appendix is Not Useless

You may have had your appendix removed because doctors believed that it was a useless vestigial organ. Now researchers have found that it serves as a storage tank for healthful germs that live in your intestines. These good bacteria help to break down food so you can absorb its nutrients. They also prime your immune system to recognize harmful germs and prevent them from invading your body, prevent your immune system from attacking your own body to cause auto-immune disease, and produce immune factors that may prevent colon cancer (Microbiology, February 9, 2009).

When you have diarrhea, bad bacteria can remove the good bacteria in the intestines and colon. A study from Duke University shows that the bad bacteria cannot dislodge the good bacteria from the appendix because its inner lining is covered with a thicker and far more potent biofilm (a layer of bacteria, mucous and immune system cells) than is found in the intestines (Journal of Evolutionary Biology, August 2009). No matter how severe the diarrhea or how extensively the bad bacteria drive out the good bacteria from the intestines, the good bacteria persist in the appendix and eventually re-colonize the rest of the intestines. More on good bacteria