| Home | FoodFocus Home Page | About FitFocus|

Some Potential Risks with Physical Activity

• Arthritis
• One More Cold per Year
• Female Athletic Triad
• Heart Attack
• Running Injury

---

Arthritis Arthritis refers to diseases of joints. It is clear that some exercise is essential for joint health as it improves nutrient flow to the joints. It is also clear that repeated stress on joints or over use of joints that have been damaged will result in joint damage. For most people, normal exercise poses little risk to joints compared to its considerable benefits. Elite sports that stress joints like soccer, previous joint injury or other joint problems, a genetic predisposition to osteoarthritis and obesity increase the risks of joint problems considerably.

There are two basic kinds of arthritis.

• Rheumatoid arthritis arises from a reaction of the immune system to normal body components and joints become inflamed. Exercise induces changes to the immune system which seem to help the body regulate inflammation. Exercise seems to improve physical performance without making the disease worse. Traditional treatment with rest can cause a reduction in physical condition. (Reference: “Autoimmune disorders, physical activity, and training, with particular reference to rheumatoid arthritis.”, RJ Shephard, PN Shek, Exercise Immunology Review 1997; 3:53-67)
• Osteoarthritis refers to joints wearing out. The cartilage which provides normal joint lubrication, cushioning and spacing is damaged through injury or repetitive loading. Increased friction with joint movement causes pain and irritation.

  Many studies of arthritis deal with those who are at relatively high risk because of the stress they put on their hips and knees. It is important to remember that for many healthy active people, activity improves their joints. One study found that, compared to being sedentary, women who reported activities with “low” joint stress had about a 40% lower risk of hip or knee arthritis and those who reported “moderate/high” joint stress activities had about a 75% lower chance of arthritis. Results for men were less protective (about a 40% lower risk for “moderate/high” joint stress activities). (Reference: “The association between joint stress from physical activity and self-reported osteoarthritis: an analysis of Cooper Clinic Data”, Osteoarthritis Cartilage 2002 Aug:10(8):617-22)

Your Risk of Arthritis

If you are assessing your risk of arthritis associated with physical activity, you should consider:

• 1) Sports such as soccer – Soccer subjects the knee to considerable stress and knee damage is common. One study concluded that x-rays of about 50% of elite soccer players show signs of arthritis after 15 years but that below the elite level, there did not seem to be an increased risk.

  Injuries to the knee (the ACL or anterior cruciate ligament) are common in soccer, basketball and volleyball. Women in basketball are twice as likely and women in soccer are four times as likely to suffer such a knee injury as men are. This is attributed to women not bending their knees as much as men when landing from a jump and not learning to crouch when pivoting to reduce knee stress. Strength and training are needed to reduce such injuries to female athletes. (Source: web site of the American Academy of Orthopaedic Surgeons, www.aaos.org)

• 2) Previous joint injury or other joint problems- Once you have damaged your knees, they are more susceptible to further damage and to the development of arthritis. One study concluded that athletes with previous knee injuries were almost 500% more likely to have arthritis in the knee than other athletes.

  Even if you have not injured your knees, you could be more likely to get arthritis if you have abnormal joints (due to alignment or joint stability) or if you have inadequate muscle strength or muscle imbalance. One of the ways that you can protect your joints is to maintain or improve muscle strength and general conditioning because strong muscles stabilize your joints and act as shock absorbers to protect your joints.

• 3) Your genetic predisposition to arthritis- If you have a family history of osteoarthritis, you may experience pain and arthritic symptoms earlier if your activities stress your knees or hips. For example, animal studies indicate that arthritis develops twice as quickly when mice susceptible to arthritis are allowed to run regularly. (Reference: “Lifelong voluntary joint loading increases osteoarthritis in mice housing a deletion mutation in type II procollagen gene, and slightly also in non-transgenic mice.”, T Lapvetelainen et al, Annals of the Rheumatic Diseases, 2002 Sep;61(9):810-7)
• 4) Your weight- A study of former top-level athletes found that arthritis of the knee was as common in weight lifters as it was in soccer players (about 30%). This was attributed to the high body mass of weight lifters. If you are obese, losing even a few kilograms may help you delay or even avoid future pain and disability from arthritis of the hip or knee.
• 5) Time spent doing heavy work- Every year you spend doing heavy work or work that involves kneeling or squatting is believed to increase your risk of arthritis of the knee by about 10%.
• 6) Time spent running- Because running is a popular exercise which subjects knees and hips to high impacts, the possible added risk of arthritis is top level athletes and in recreational runners has been extensively studied. In general, either no added risk was found or the slight added risk was minor compared to other health benefits.

  A study of top-level middle-aged Finnish orienteering runners found that the runners reported more knee arthritis and pain but not more hip problems or pain. In spite of that, runners had less disability from hip or knee pain. A big advantage for the runners was that their risk of heart attack was only 15% of that of non-runners. (Reference: “Heart attacks and lower-limb function in master endurance athletes”, UM Kujala et al, Medicine and Science in Sports and Exercise, 1999 Jul;31(7):1041-6)

  One study of female ex-elite athletes found that long distance runners had a 200-300% increased risk of arthritis and that a small subset of runners from the general population who reported similar long-term vigorous exercise seemed to have a similarly increased risk.

  Studies of older runners (aged about 60-80 at the end of the study) concluded that runners had greatly reduced risks of disability and death.

  Another study of older runners (median age 63 years) found that running did not speed up the development of arthritis. With aging, both runners and non-runners developed arthritis of the hands and knees at about the same rate (about 13% over a period of 5 years).

  Runners who had run 20 to 40 km/week (12 to 24 miles/week) for a median of 40 years did not show increased risk of arthritis of the hips, knees or ankles compared to non-runners.

  Runners aged 50 to 72 years did not show any increased risk for arthritis compared to non-runners and their rate of disability was only about 10% of the disability rate for non-runners. (Reference: “Aging, long-distance running, and the development of musculoskeletal disability. A controlled study”, NE Lane et al, American Journal of Medicine, 1987 Apr;82(4):772-80)

  Furthermore, a group of similar runners had 40% more bone mineral than non-runners.

Reducing Your Risk of Arthritis

Most people who suffer from arthritis are over 55 years of age, are obese or have a family history of osteoarthritis or are younger, active people with a significant joint injury. If you want to, or have to, take extra care to preserve your knees:
• a) Choose smooth, low impact activities like stretching, swimming, water aerobics, cycling, walking on a treadmill, playing golf rather than activities like running, tennis, racquetball, basketball, baseball or soccer that are high impact and may twist the joints.
• b) Maintain muscle strength to better protect your joints. If you continue to play sports that put your knees at risk, learn to land from a jump or pivot so as to reduce the stress on your knees and develop strength to protect your knees.
• c) Stay active. The recommended exercise for patients with osteoarthritis is the same as the recommendations for physical activity for good health because aerobic exercise and strengthening exercise have positive effects on pain and function. Exercise is superior to other approaches that may reduce pain but not improve function. (Reference: “Physical activity can influence the course of early arthritis. Both strength training and aerobic exercise provide pain relief and functional improvement”, E. Roos, Lakartidningen 2002 Nov 7;99(45):4484-9)

One More Cold per Year Active living provides a variety of beneficial effects and many habitual exercisers believe that they benefit from improved resistance to infection and have fewer colds. However, one study indicates that increasing total distance run per year increases one’s chance of having an upper respiratory tract infection (URTI) indicated by a runny nose, a sore throat or a cough (i.e. the further you run, the more likely you are to get a cold).

The study also noted that males who did not use alcohol were at a significantly reduced risk of an URTI but males who did use alcohol where at a much higher risk for an URTI. The increased risk of illness for males using alcohol (about 500%) was much greater than that of even the most active runners. Another study found that the risk of an illness was fivefold higher for runners 1 week after a marathon than for runners who trained but did not compete in the race. While having one more cold per year is, for most people, a relatively minor matter, the topic is a reminder that the effect of exercise on the immune system is not a simple one. Too much physical stress (running a marathon) or other activities ( males consuming alcohol) may reduce your immunity.

Female Athletic Triad A female athlete who goes to extremes in eating too little and/or exercising too much can cause long-term damage to her health. Girls and women who are most at risk are those in sports where thinness is rewarded for appearance (i.e. figure skating, ballet, gymnastics) or for performance (i.e. distance running, rowing), who are susceptible to social pressures that encourage unhealthy low weight levels and who continuously focus on weight.

The “female athletic triad” describes three interrelated illnesses:

• 1) An Eating Disorder
• 2) Menstrual Dysfunction: Poor nutrition, low calorie intake, high energy workout, physical and emotional stress or low body fat can lead to hormonal changes that stop menstrual periods.
• 3) Osteopenia which is a condition in which a person has a reduced bone mass. Although it hasn’t yet resulted in any fractures, it marks the first stages of bone deterioration that may lead to osteoporosis.

Disordered eating may include starving yourself (anorexia nervosa), cycles of eating and throwing up (bulimia), severely restricted food intake, prolonged fasts, use of diet pills, diuretics and laxatives. Excessive exercise may also be used to keep weight down.

Amenorrhoea is a condition in which women exercise so much that they stop menstruating. Runners with low body fat, increased running distance, poor nutrition with low intakes of calories, protein and fat are at increased risk. Amenorrhoea can result in reduced bone density.

Reference: “Health Effects of recreational running in women. Some epidemiological and preventive aspects.”, Sports Medicine, January1991; Vol. 11, No. 1: pp20-51

The link between distance running, poor diet, amenorrhoea and bone loss is troubling. Amenorrhoea may reduce the mineral content of bone many years before old age suggesting serious long-term health consequences. Fortunately women who reduced their running distance by 43% and took supplemental calcium increased body weight by 5%, improved estrogen levels so that they began to menstruate again and their bone mineral content improved.

While the majority of bone-loss problems in athletes have been in women, men are not immune. One 22 year old male marathon runner started to experience skeletal fractures including a fracture of his pelvis and multiple compression fractures of his vertebrae. His strenuous exercise combined with an eating disorder (he suffered from anorexia nervosa) had resulted in weight loss and a serious loss of bone density.

Regular exercise which puts pressure on your bones is a good thing but extreme amounts of exercise combined with very poor nutrition can be very damaging- particularly for women.

Reference: “Preventing Osteoporosis”, K. H. Cooper, 1989, Bantam Books

Recognizing the female athletic triad is the first step to prevention and treatment. Eating disorders, missing several menstrual periods or a stress fracture in sports are warning signals to contact professional help.

Heart Attack Active living is essential for heart health, however vigorous activity temporarily increases the risk of a heart attack. Someone diagnosed with heart disease must follow doctors’ instructions to avoid risk of heart damage or death. Unfortunately not everyone with heart disease has had their condition diagnosed and vigorous activity is particularly dangerous for these individuals. That is one reason why those who are middle aged and older should consult their physician before beginning any strenuous physical activity.

Sudden death is not only a risk for those who are older or have undiagnosed heart conditions. Young Swedish male orienteers experienced increased death rates due to heart disease associated with heart infections. It is believed that exhaustive and long-lasting exercise caused temporary losses of immunity and increased infections leading to heart damage. Changes to training programs and competitions including avoiding strenuous exercise during illness reduced these unnecessary deaths. Avoiding strenuous exercise during the flu or viral infection can prevent premature and possibly undetected heart damage.

Reference: “Interaction between infection and exercise with special reference to myocarditis and the increased frequency of sudden deaths among young Swedish orienteers 1979-92”, G. Frieman et al, Scandinavian Journal of Infectious Diseases, Suppl. 1997; 104: 41-9

Heart problems may also exist from birth. A competent medical examination should always precede competition. Anyone whose family members had premature or exercise-induced deaths should be examined before beginning an exercise program.

Speed training, sprinting and interval training may be fine for healthy people done in moderation with proper planning and they may be useful to develop peak performance but they have no place in a program for enhancing health.

It is essential to listen to your body. Chest pressure or pain, numbness or tingling in the arms, neck or jaw, unusual shortness of breath, fatigue or sweating, dizziness or irregular or unusually rapid heart rate are signs to stop exercising and report the symptoms to your doctor. Some high profile people who died exercising experienced chest discomfort during exercise but failed to get medical attention.

“Weekend warriors” who do strenuous exercise without first working themselves into shape increase their risk of a heart attack by a factor of 50 to 100 (compared to not doing anything active for the same period).

Reference: “Conquering Heart Disease: new ways to live well without drugs or surgery”, Harvey B. Simon, M.D.; Little, Brown and Company,1994, p150-152

People who exercise regularly do increase their risk of a heart attack during vigorous activity and shortly thereafter to about twice that of a sedentary person who is not active during the same period but the increased risk in only temporary and it should not be over-emphasized.. Overall the person who exercises regularly has about a 60% lower risk of a heart attack than a person who is sedentary. By making sure that you do not have any health problems that put you at particular risk, by paying attention to any warning signs, by developing your ability for vigorous exercise slowly and by doing proper warm-ups and cool-downs, you minimize your risk. If you are habitually active, you could expect to exercise for hundreds of years before your additional risk of a heart attack becomes significant (ie 30 cases of cardiac arrest per 100 million person hours of intense activity for habitually vigorous men).

Reference: “The Disease-specific Benefits and Risks of Physical Activity and Exercise”, David S. Siscovick et al; Public Health Reports, March-April 1985, Vol. 100, No. 2, pp180-188

Running Injury Running is a common form of aerobic exercise that is beneficial to the cardiovascular system but it is associated with a relatively high rate (24%-65%) of injury.

Most injuries involve the knee, foot or ankle. A wide variety of factors have been considered such as training habits (distance, intensity, pace), lack of stretching or warm-up exercises, shoes, running surface, body mass index, etc. The risk of injury seems to depend primarily upon the total distance run.

While most injuries are overuse injuries, a significant number are due to running on an uneven or slippery surface. A few percent of injuries are due to being attacked by a dog, hit by a car or bicycle, hit by a thrown or flying object or by running into a stationary object.

Reference: “The Ontario Cohort Study of Running-Related Injuries”, S. D. Walter et al, Archives of Internal Medicine, Vol. 149, November 1989, p2561-2564

Running experience also seems to be a factor with experienced runners having much lower rates of injury than those who have been running for 2 years or less.

GO TO.... | Home | FoodFocus Home Page | About FitFocus|