Performance limits in older adults (“Oh to be __ again!”)
I recently completed a six-day bike tour of California. It’s my goal each winter to escape the post-holiday gloom of frigid New York and head for warmer climes. So far in previous winters I’ve ridden Arizona, Death Valley, and Costa Rica.
My objective is to be neither the oldest nor the slowest in my cohort of cyclists; that, and not inflict grievous bodily harm on myself. In those goals, I succeeded. I was challenged but not pushed into the “red zone”. East Coast outdoor rides and indoor spin classes prepared me adequately for the effort.
I covered 163 miles in total with cumulative climbs of over 5000 feet. Don’t be too impressed—a Tour de France competitor might polish that off in a day.
Nevertheless, while I feel in great condition at 72, age does make a difference. I wonder how much longer it will be before I succumb to the temptation to opt for an e-bike, as did the majority of my fellow riders, ranging in age from 60s to 70s.
Sad truth is that, try as we might, we’re all prey to the inevitability of progressive physical performance decline with age.
For instance, the world record for the 100-meter dash is 9.58 seconds, set by Usain Bolt at the age of 25, when most athletes attain peak performance.
By age 50, the record time drops to 10.88 seconds; by 70 it’s 12.59 seconds. Remarkably, there’s a 105-year-old who completed it for a Senior Olympics age-group milestone—but it took her 63 seconds! There probably wasn’t a lot of competition.
For feats of strength, consider the world record for the bench press in age group 18-39 for a person of my body weight (165 pounds): An astounding 539 lbs!
By age 60-69, even an accomplished lifter of comparable weight usually bench presses only 185 pounds.
According to one study, “the aging process leads to distinct muscle mass and strength loss. Muscle strength declines from people aged <40 years to those >40 years between 16.6% and 40.9%.”
Maximum physical capacity is usually attained between 20 and 29 years of age. After 30, sorry, it’s just downhill. The extraordinary career longevity of outliers like Tom Brady and Novak Djokavic are the products of fierce conditioning and acquired wiliness that surmounts their chronological limitations.
A slippery slope comes after age 70 for most people; that’s when the steepest drop-off often occurs.
There are multiple reasons for diminished physical capacity with age. Among them:
Cardiovascular: Arteries stiffen, cardiac output declines, and lung capacity is reduced, thus providing less blood flow to muscles. A measure called VO2 max, charting the ability of the body to utilize oxygen under peak demand, tells the story. A champion elite athlete in their 20s might have a VO2 max as high as 80 or 90, while the average VO2 max for a 20-something male is 34-44 (for women it’s slightly lower).
By age 60-69 that average declines to 23-36. Strive as I might, I’m happy when my VO2 max clocks in at 40, which is good for my age, but middling for a young person.
Neurological: This is a brain and neural circuitry problem. Response times inevitably slow; balance deteriorates; spinal impingements weaken brain connections to extremities.
Mitochondria: With age, the ability of mitochondria to generate energy inexorably declines. This is the result of mutations, cumulative wear and tear, free radicals, and progressive inefficiency of self-repair (mitophagy).
Sarcopenia: We all battle age-related declines in lean muscle mass. It’s estimated the average person loses 10% of their youthful muscle volume each decade starting at around 40.
IMAT: A relatively new discovery, intramuscular adipose tissue (IMAT) speaks to the quality, rather than the quantity of muscle. Imaging of muscle in aged, deconditioned subjects reveals extensive “marbling” with fat infiltration. This is a sign of impaired metabolism, associated with weakness and poor endurance.
Insulin Resistance: A high percentage of Americans have metabolic syndrome, a condition that often worsens with age. As a result, even in the presence of sometimes elevated blood sugar, glucose can’t get into muscle cells to provide fuel for energy. Hence, muscles suffer a form of “brownout”, which can impede performance.
Obesity: In addition to burdening muscles, joints, and the heart, excess weight is often associated with insulin resistance, IMAT and inflammation.
Joints: It’s not just wear and tear associated with mileage. In a process called “inflamm-aging”, cartilage is progressively eroded by chronic inflammation; there’s also a tendency for collagen to degrade over time, subject to free radical damage and glycation, forming AGEs—advanced glycation end products which are dysfunctional biomolecules. Moreover, menopause—and its male equivalent andropause—result in shrinkage and desiccation of cartilage. The cushioning between joints becomes more fragile and susceptible to tearing or fracture.
Hormones: Age-related declines in anabolic hormones like testosterone, DHEA and growth hormone in both sexes cause reductions in muscle size and strength. Moreover, anabolic resistance worsens; muscles respond less to hormones, dietary protein and resistance training. Six-packs and bulging biceps become more elusive.
Recovery: Consistent workouts are the key to performance. But as we age, our downtimes are prolonged, undermining conditioning. Injury healing is slowed and muscle stiffness increases. Delayed onset muscle soreness (DOMS) is accentuated. A recent review states, “it is evident that aged muscle displays delayed, prolonged, and inefficient recovery. These changes can be attributed to anabolic resistance, the stiffening of the extracellular matrix, mitochondrial dysfunction, and unresolved inflammation as well as alterations in satellite cell function.”
Digestion: Older adults are more prone to digestive woes. The capacity of the aging GI tract to digest and absorb nutrients declines. This may constrain the bioavailability of structural building blocks for muscle maintenance.
Drugs: Certain medications can slow us down. In particular, beta blockers may prevent users from attaining maximal heart rate; statins sometimes cause muscle pain and weakness; and PPIs may cause magnesium, iron, or B12 malabsorption, curtailing strength and endurance. And, of course, there are the new ultra-popular weight loss drugs that produce dramatic weight loss—but often deplete significant amounts of muscle reserve.
Psychological: There’s no question that a certain amount of inertia and risk aversion sets in with advancing age. Achiness and fatigue can prompt a descent into sedentary habits. A maladaptive mental attitude thwarts the initiative to mobilize.
What to do? Fortunately, aging bodies are not like jalopies, inexorably destined for the junk heap. To borrow a term from Nassim Taleb, humans are “anti-fragile”; we have dynamic, reparative responses to stress, if applied judiciously.
Therefore, consistent vigorous and challenging—but not injurious—exercise is an antidote to many of the ravages of aging. Resistance workouts especially help rejuvenate muscles. Make stretching or yoga part of your routine, too.
In addition, adequate dietary protein counteracts sarcopenia. Active seniors should strive to consume up to a gram of protein daily for each pound of lean body mass.
Avoidance of ultra-processed food is imperative; so, too, dialing down carbs and refined vegetable oils.
The following supplements are also excellent for staving off performance declines: