U.S. swimmer Diana Nyad, 61, set out to swim from Cuba to Florida on Aug. 7,… (Enrique de la Osa, Reuters )
For the last 20 years, Bob Unger has cycled or run religiously three or four times a week. As a gift to himself for his 65th birthday in November, he decided to begin working out every day, or nearly. "I feel so much better," says Unger, a Boulder, Colo., psychologist and an avid bike racer. "It helps everything,"
On an afternoon in August, Unger is at the Boulder Center for Sports Medicine. He's here to get a battery of tests — the kind that helps elite and hard-core athletes like him figure out their optimal workout intensity so they can train accordingly.
Electrodes are taped to his chest as he cycles in place; wires run from the electrodes to an electrocardiogram device that reads his heart rate and records any irregular blips.
Adam St. Pierre, an exercise physiologist, draws blood samples to obtain Unger's "lactate profile," which tells him how Unger's body is responding to the workload: The harder you work, the more lactate you produce.
And he tests Unger's VO2 max, or maximal oxygen consumption — a measure of aerobic potential. For more than an hour, Unger pedals at various intensities until finally, heaving for air and with rivers of sweat running down his arms and legs, he is close to collapse.
Unger's lactate profile and VO2 max numbers have improved since his last test in March — in fact, this is his best physiology performance since the center began testing him nine years ago. Unger's heart is pumping more efficiently with fewer beats, and that's impressive. As a rule, starting in the late 30s, VO2 max steadily declines.
"Bob is an anomalous example of how much improvement is possible after age 60," St. Pierre says. "He's a good example that with proper training — enough training — people of any age can get fitter. You can be better at 65 than perhaps you were at 45, even at 25."
A slew of elite and master athletes (those 35 and older) are pushing the bounds of what once was thought possible for middle-aged and older athletes.
Dara Torres — who at 41 was the oldest swimmer ever to make the Olympic team — captured three silver medals in freestyle swimming and relays at the 2008 summer Olympics.
Diana Nyad, who just turned 62, attempted to swim the 103-mile stretch from Cuba to Key West, Fla., without a shark cage; though she was ultimately beset by an asthma attack, shoulder pain and choppy waters, she tackled a swim she had last attempted at age 28 and that would be daunting for an athlete of any age.
Ed Whitlock, a runner from Canada, became the oldest person to run a marathon in under three hours in 2003, at the age of 73.
These days, runners in their 60s and 70s have surpassed the winning time for all ages for sprints and marathons at the first Olympic Games held in Athens in 1896.
What enables older athletes like these to continue to perform with such excellence? That's not entirely clear to researchers. Genetics, experience, training and stellar fitness all play a role, and scientists are trying to learn just how far these variables can go in counteracting the inevitable physiological declines that happen with aging.
But one thing does seem clear: When it comes to elite athletic performance, aging "is not a death sentence," St. Pierre says.
Consistency is a clear factor in Unger's improvement — and the performance of any serious athlete, St. Pierre says. "A lot of people will have a really good week or a really good couple of days, but stringing together months and months and years and years is what it takes to be a really successful aerobic athlete."
This is certainly true for Nyad, who dove back in the water in 2009 to prepare for her 60-hour swim after taking a 30-year hiatus from the sport. Training included multiple 8- to 15-hour swims and one that lasted 24 hours. During it all, she says, she found herself feeling stronger and more resilient than when she was training in her 20s.
"I know most athletes, just human beings in general, you recuperate slower as you get older," she says. "I must say that I haven't found that."
The biggest downer for people as they age is that their cardiac output (the amount of blood that pumps out of the heart in one minute) is steadily decreasing, says Sandra Hunter, an associate professor of exercise science at Marquette University in Milwaukee, Wis. This occurs because the heart rate decreases by about one beat per year beginning in a person's late 30s. What this means is that "our maximal heart rate will decrease, regardless of how active we are," Hunter says.
The consolation prize? "Your ability to do sub-maximal exercise, which is what most exercise is, remains really excellent," says Michael Joyner, a professor of anesthesiology and an exercise researcher at the Mayo Clinic in Rochester, Minn.