The 10 Biomarkers of Aging
We have often heard that certain products can slow down and/or reverse Biomarkers of Aging (Ageing).
“The good news is that, while you can’t turn back the calendar, you can do something to affect your biological age—the toll the years take on your body and your health.” Tufts University Health & Nutrition Letter (May 2006)
“Strength training is really the key to the Biomarkers program.” Tufts University Health & Nutrition Letter
What ARE the Biomarkers of Aging?
Biomarkers (Simon & Schuster, 1991) has stood the test of time impressively, says Tufts University Health & Nutrition Letter (May 2006). “While research has of course added to our knowledge about all 10 of thebiomarkers described in the book, the basic lessons still hold true today.”
For many years, aerobic exercise was thought to be practically synonymous with good health. Weight training or bodybuilding was considered mainly cosmetic. That changed with the publication of Biomarkers by William Evans, PhD, and Irwin H. Rosenberg, MD, professors of nutrition and medicine, respectively, at Tufts University. Strength training took its rightful place as an equal partner with aerobics. Moreover, strength training became the senior partner for taking the worry out of aging.
The book features landmark studies at the USDA Human Nutrition Research Center on Aging (HNRCA) showing that people past middle age are able to gain muscle and increase strength by as much as 200%. What’s more, muscle and strength were found to be the key controllable physiological factors associated with aging. One 93-year-old study participant observed: “I feel as though I were 50 again…Pills won’t do for you what exercise does!”
The HNRCA was and is located at Tufts University. Evans was the Chief of the Human Physiology Laboratory at the HNRCA; Rosenberg was the Director and subsequently became dean of Tufts’ Friedman School of Nutrition Science and Policy. Both have moved on to other posts. Quite appropriately, Tufts University Health & Nutrition Letter (May 2006) includes a Special Supplement assessing how well the 15-year-old program for controlling the aging process has stood the test of time.
“The bottom line of Biomarkers remains as true now as then,” they conclude: “Exercise is the key to a healthy and rewarding old age. Even for the frail elderly—and this is still a bold concept—a regular exercise program can have a strong positive health impact. A combination of regular aerobics, flexibility and strength training is the best strategy for retarding—even reversing—the effects of aging on the 10 biomarkers the authors identify.”
The 10 Biomarkers
To paraphrase Satchel Paige, the ageless baseball pitcher, biomarkers are those things that tell how old you would be “if you didn’t know how old you was.” In Biomarkers, Evans and Rosenberg isolated the following signposts of vitality that can be altered for the better by changes in lifestyle:
- Lean Body (muscle) Mass
- Basal Metabolic Rate
- Body Fat Percentage
- Aerobic Capacity
- Blood Pressure
- Insulin Sensitivity
- Cholesterol/HDL Ratio
- Bone Density
- Body Temperature Regulation
Significantly, all 10 biomarkers can be revived or improved through strength training.
To help people understand how strength training affects the biomarkers, the authors coined the term “sarcopenia” to describe an ailment that affects many old people and deprives them of their independence. “Sarco” refers to flesh, “penia” means a reduction in amount. So sarcopenia describes an overall weakening of the body caused by a change in body composition in favor of fat and at the expense of muscle.
Evan and Rosenberg say that the first biomarker, muscle mass, is responsible for the vitality of your whole physiological apparatus.
Muscle mass and strength, the second signpost, are our primary biomarkers. They’re the lead dominoes, so to speak. When they start to topple, the other biomarkers soon follow. On the other hand, when muscle mass and strength are maintained, the other indicia are likewise maintained. That is where strength training comes to our aid.
Aerobic exercise and diet are important, but strength training, according to the authors, is pivotal if you want to stay young longer.
Fifteen Years Later
“Since the publication of Biomarkers, subsequent research has continued to support [the authors’] basic premise,” says the Tufts Supplement. Exercise and diet are the keys to successful aging.
Let’s look at a few points of special interest highlighted in the Tufts Supplement.
First, the average middle-aged person may be inclined to focus on losing or maintaining bodyweight. That’s not good enough. Your target should be body composition, improving your ratio of muscle to fat. The key is to minimize “biologically inactive” fat tissue and maximize “biologically active” muscle mass.
“People with a greater ratio of muscle to fat enjoy a higher metabolism and don’t have to worry as much about gaining weight or about how much they eat—that active tissue burns more calories.”
Conventional wisdom that muscle mass and strength decline with age, accelerating after 45, is wrong. “If you use your muscles frequently, you can maintain their strength. But if you push your muscles to the limit of their capacity by exercise, you can actually increase their strength—no matter what your age… The fact is that you can regain muscle mass and strength, no matter your age or what shape you’re in now.”
One more key point regarding strength training, one often over looked: “To be effective, strength training must be progressive, or you won’t get full benefit; as the intensity of your activity increases, so will your strength.” In short, don’t rest on your laurels; keep trying to improve, slowly and carefully, but persistently.
As we say above, aerobic exercise is important, but strength training is central to staying young longer. In point of fact, strength training increases the effectiveness of aerobic exercise, especially for older athletes. Here’s why, as explained in the Tufts Supplement.
“While both young and older people benefit from regular aerobic exercise—the kind that makes you huff and puff—the positive changes in older people come almost entirely in the muscles’ ability to utilize oxygen (oxidative capacity), rather than in the heart or cardiovascular system.” That’s another reason why you need the added muscle mass which comes from strength training. “When you build muscle, you create more muscle cells to consume oxygen. The more demand for oxygen from your muscles, the greater your utilization of oxygen and your aerobic capacity.”
Flatten Your Health Span
The ultimate goal of controlling your biomarkers is to extend your years of good health and compress your years of decline. By making positive changes in your biomarkers through a combination of exercise, especially strength training, and eating right, you can “prolong vitality, postpone disability, and prevent the development of sarcopenia.” The latter is very important, according to the Tufts Supplement. The price of sarcopenia is “loss of balance, reduced mobility and the frailty so often seen in the elderly.” Making the right lifestyle changes early on can postpone—sometimes for decades—what Evans and Rosenberg call the Disability Zone. “You can greatly improve your odds of approaching the ideal: a health span that almost matches your life span.”
The first step is to understand the 10 biomarkers. I’ve been encouraging people to read Biomarkers since it was published. I hope this 15-year assessment will motivate those who haven’t read this landmark work to do so now, and those who read before to read it again.
Measurement & Validity
While some potential biomarkers might be theoretically very accurate, it may be impossible or unethical to obtain them. Accurately counting the number of remaining functional brain cells, for example, would result in the death of the individual being assessed. Measuring the ability of the individual to recover from some extreme stress like pain or cold would be unethical.
In order for a biomarker of aging to be useful, certain criteria need to be met. These criteria include the following:
- The rate at which the biomarker itself changes should reflect some measurable parameter that can be predicted at a later chronological age. For example, if the biomarker were rate of change in memory ability, it should be tied to a particular memory phenomenon that can be predicted at a known interval (e.g., one year) and can be measured (e.g., numbers recalled from a list after a few minutes of intervening activity).
- The biomarker should reflect some basic biological process (e.g., heart rate).
- The biomarker should not reflect disease (e.g., Alzheimer’s disease).
- The biomarker should be widely reproducible across similar species (e.g., all mammals).
- The biomarker should not cause harm to the individual being assessed.
- The biomarker should be reproducible and should be measurable in a relatively short time interval compared to the life span of the organism being assessed (e.g., days for fruit flies and months for humans).
A major problem in biomarker research is determining the validity of the biomarker. Validity of a biomarker means that it measures what it purports to measure, that is, rate of aging. Finding that a particular measure goes down in some predictable fashion as the organism ages does not mean that the measure reflects biological age. For example, skin wrinkles with advancing age, but skin wrinkling is almost entirely the result of exposure to sunlight and is exacerbated by smoking. Thus, skin wrinkling is a measure of exposure to environmental damage. Some individuals show little or no wrinkling because of lifestyle choices. Similarly, hair turns gray with advancing age. Some individuals are fully gray by their thirties while others show little gray at very advanced ages. While we all see graying hair as a symbol of age, graying hair is not a good predictor of remaining life. It is therefore not a good biomarker. Still other measures, like rings in the trunk of a tree, may be good chronometers (measures of the passage of time) but still not be good biomarkers (a ten-year-old tree of a short-lived species will have as many rings as a ten-year-old tree of a long-lived species).
BIOMARKERS, The 10 Keys To Prolonging Vitality
A Fireside Book Published by Simon & Schuster