We have all heard it so many times, exercise is good for the heart, keeps you slim, and makes you feel good. But I find that people forget just how good exercise is at slowing down aging. Have you ever wondered if your intense exercise program was shortening your life? Could raising your metabolic rate over time lead to accelerated aging? According to the medical literature…apparently not. In fact most of the research indicates that sports such as XC skiing, bicycling and running extend life span. There are over thirteen thousand papers in the medical literature on exercise therapy. It is one of the most powerful tools we have for changing physiology and modifying disease progression. I have found that people don’t exercise regularly enough and get lazy in the winter or summer depending on his/her preferred sport. Taking too much time off can be a disaster for your conditioning as well as your waistline. In this article I will discuss how exercise can slow down aging and keep you living a longer and healthier life.
Exercise Increases Antioxidant Defense Enzymes
A leading theory in the study of how we age is the “free radical theory.” The upshot of this theory is that the accumulation of free radical damage to our cells and a less efficient system for repairing this damage largely determines how fast we age and when we die. Athletic training teaches your cells to make more antioxidant enzymes. This is an adaptation of training. At high altitude we “go anaerobic” more easily and this puts extra stress on the antioxidant defense system because anerobic metabolism creates more free radicals. High-intensity endurance training actually trains your body to make more antioxidant defense enzymes. Having a good antioxidant defense system plays an important role in preventing cancer, heart disease, dementia, vision loss and sun mediated skin damage.
The best study to illustrate in increase in antioxidant defenses was done by Hellsten et al. in 1996 on 11 young men. Training was performed three times per week for 6 wks followed by training two times per day for 7 consecutive days. The exercise used in this study consisted of repeated “all out” 10-second sprints. The graph below (from Hellsten et al.) shows increases in the activity of three key defense enzymes before and after 6 wk of sprint cycle training and 3, 24, and 72 hours after additional 1 wk of more frequent sprint training sessions. All biopsies were obtained at rest after training. The results show that antioxidants defence enzymes increase due to high intensity training.
In 2000 Tonkonogi et al. researched whether regular aerobic training would also have this effect of defense enzymes. They could not reproduce the results from the study by Hellsten et al. They concluded that only high intensity training has this effect.
Growth hormone (GH) is a key anti-aging hormone, helping burn fat, build muscle, give you younger looking skin, improve athletic performance, improve deep sleep, and helping you heal faster. Keeping high normal levels GH help fight aging. Lower than normal levels can cause fatigue, weight gain, and poor athletic performance. Growth hormone levels decrease with age. The gradual decline in growth hormone production in both men and women begins at approximately age 30 and continues at a steady rate throughout life. Adult growth hormone deficiency is a condition where levels are much lower than normal. Growth hormone should not be taken without medical supervision because it may also make cancers grow faster by increasing a substance called IGF-1.
Most (> 85%) of the growth hormone (GH) that your body makes is released in bursts either during deep sleep, fasting or exercise. Acute aerobic exercise makes GH go up in adults through the third decade of life. Low-intensity (but not maximal aerobic) exercise stimulates greater GH release in young women than men The reasons for this are not known. Like most hormones the body GH has what we call negative feedback, that is, as levels of GH rise production decreases. However, exercise is unique in that it can overcome this negative feedback. In fact, two or three consecutive bouts of exercise can cause consecutive GH bursts. Generally, harder efforts give bigger bursts of GH. High intensity skiing, cycling, running, or weight lifting will produce spikes in GH whereas long duration, lower intensity workouts will tend to raise GH levels less but keep the level higher over a longer period of time. Interestingly, estrogen enhances the effect of exercise on growth hormone levels and thus may provide some rationale for natural estrogen replacement in the menopausal or postmenopausal female athlete. The take-home message is that intense workouts boost GH, nature’s most powerful anti-aging hormone.
Testosterone and Estrogen
Resistance exercise (weight training) tends to raise testosterone in men for the short term and lower it during recovery depending on the fitness level and age of the individuals tested. Endurance exercise tends to decrease testosterone in men depending on the fitness levels and intensity of effort. Highly trained female athletes tend to have lower estrogen levels and less risk of breast cancer. Elevated estrogen is considered by be risk factor for breast cancer. If you want to check your testosterone level make sure you ask your doctor to measure both free and total testosterone.
Animal studies have found that aerobic exercise boosts cellular and molecular components of the brain, and exercise has improved problem solving and other cognitive abilities in older people. A new study in the February 2005 issue of the Journal of Gerontology: Medical Sciences is the first to show this in humans. Through studying brain scans of men and women age 55+, researchers have found that men who regularly worked out lost significantly less brain tissue as they aged than men who exercised rarely or not at all. Exercise is also well known for its ability to fight depression and stress. Depression and stress have independently been associated with cardiovascular disease and early mortality.
In the April 27, 2005, issue of The Journal of Neuroscience it was reported that physical activity inhibits Alzheimer’s-like brain changes in mice, slowing the development of the disease. The research demonstrated that long-term physical activity enhanced the learning ability of mice and decreased the level of plaque-forming beta-amyloid protein fragments, a characteristic of Alzheimer’s disease.
Weight bearing exercise increases bone density. Although approximately 97% of bone mass is achieved by the age of eighteen, increases in bone density have been observed in one’s 30’s. In some cases, even moderate increases in physical activity by women in their twenties can increase bone density. A major benefit of exercise in older people is also its ability to improve balance and maintain muscle mass, thus reducing fracture risk. It should be noted that if exercise causes amenorrhea (loss of period) then bone health could be adversely affected. Any pre-menopausal woman who has missed more than three periods in a row should see a physician.
Most of us know that being overweight increases our risk for heart disease, cancer, osteoarthritis, and diabetes. A good way to live longer is to not get these diseases. A study by the Norwegian Institute of Public Health found that overweight teenagers are 50 percent more likely to die in middle age than their thinner friends. The survey of 227,000 Norwegian teenagers was carried out over 30 years and found that boys that were obese were 80 percent more likely to die. Obese girls were up to 100 per cent more likely to die.
A loss of muscle, a decrease in metabolic rate and an increase in intra-abdominal and intra-muscular fat occur with aging. Strength-training exercises can raise your metabolic rate by about 30-50 calories per day, and over the course of three months of strength training you can gain about 3 pounds of muscle, amounting to a total boost in the basal (resting) metabolic rate of 7%.
Fat deposited around the organs within the abdomen (intra-abdominal fat) is associated with hypertension, cardiovascular disease, and type 2 diabetes, among other disorders. It is also the predominant type of fat that women accumulate after menopause. A study published in Journal of the American Medical Association in 2003 demonstrated that regular exercise could reduce the levels of intra-abdominal fat in postmenopausal women.
Sweating and Detoxification
Sweating is a good way to rid the body of accumulated environmental and metabolic toxins. Sweat contains sodium, chloride, potassium, lactic acid, fatty acids, urea, glycoproteins, mucopolysaccharides in addition to environmental toxins. Environmental toxins like plastic residues (pthalates), solvents (toluene) and mercury can build up in fatty tissue and are known to cause hormonal disturbances or cellular damage. Pthalates act like estrogens in the body and are implicated in the early onset of puberty (precocious puberty) in girls. Sweat is the main route of elimination for pthalates.
Live Longer by Not Getting Cancer or Heart Disease
Cardiovascular fitness reduces the chance of getting high blood pressure, heart disease insulin resistance and diabetes. Exercise also increases your good cholesterol (HDL) while reducing the bad cholesterol (LDL) and lowers triglycerides (fat) in the blood. According to the National Cancer Institute (http://www.cancer.gov/newscenter/pressreleases/PhysicalActivity), exercise has been shown to reduce the risk of getting colon, prostate, breast, endometrial, and lung cancer
Exercise at any level will keep you looking younger and feeling younger. Scientific research supports this concept. Training at high intensity increases your antioxidant defenses and raises growth hormone more than low intensity exercise. Do not start an intense exercise program without consulting you doctor or better yet a cardiologist familiar with working with athletes (for referrals contact our office). Prevent oxidative, free radical damage to your cells by eating 3-5 servings of fruits and vegetables every day. Consider an oxidative stress test to see if you are getting enough antioxidants (available at our office). Exercise benefits those who do it at any age… its never too late to start.