Which Comes First, Cardio or Weights_ - Alex Hutchinson [71]
There was, however, a significant difference between the bone density of runners and cyclists, which suggests that it’s the repeated, jarring impacts of running that produce stronger bones compared to cycling. As a result, Hinton recommends that those who engage in activities such as cycling, swimming, and rowing consider adding a dose of either strength training or a higher-impact activity like running to their regimen. That also means that elliptical trainers, which many people turn to precisely for their softer landing, suffer from the same shortcoming. “There’s no impact force, as the steps of the machine move with you,” Hinton says.
Sports like soccer and basketball (and activities like step aerobics) offer the best of both worlds, stimulating bone health through the impact of intermittent jumping and running, as well as by building muscle strength. Hinton’s research suggests that you don’t necessarily have to lift weights, and you don’t necessarily have to run and jump either—but you need to do one or the other to make sure you’re either building muscle or getting jarring impacts.
Can exercise keep my DNA from aging?
The 2009 Nobel Prize in medicine was awarded to three researchers who discovered how DNA can be copied over and over again without being damaged. Telomeres are short lengths of DNA at the end of each chromosome that serve as a protective cap, ensuring that the delicate ends aren’t snipped when the chromosome is replicated. Unfortunately, the telomeres themselves get shorter and shorter as you get older—and once they reach a certain minimum, the cell has effectively reached the end of its life. In fact, some researchers now believe that telomere shortening is the fundamental change that underlies all aging: as your cells age, so do you.
Exercise, we’ve been told for years, is a fountain of youth. It keeps your arteries supple, your muscles strong, and your mind sharp. But it hasn’t been entirely clear how it accomplishes such diverse effects. A 2010 paper by University of Colorado researchers, published in the journal Mechanisms of Ageing and Development, offers a clue. Physiologists analyzed the telomere length and aerobic fitness of four groups of people: young (18 to 32) and sedentary, young and fit, old (55 to 72) and sedentary, old and fit. The “fit” subjects did at least 45 minutes of vigorous exercise five times a week. The two young groups had essentially the same length of telomeres. The telomeres of the old, fit group were slightly but not significantly shorter. But the old, sedentary group had dramatically shorter telomeres.
The Colorado researchers also plotted telomere length versus aerobic fitness (VO2max) for the older group. Across the board, those with higher fitness had longer telomeres. The implication is clear: vigorous aerobic exercise makes your DNA look several decades younger than it is. And that’s bad news for the sedentary group. A recent study of 780 heart disease patients, for example, found that those with the shortest telomeres were most likely to die in the following four years—a mortality risk that couldn’t be explained by other known risk factors in these patients.
It’s important to note that the Colorado study can’t distinguish correlation from causation. It’s possible that a hidden underlying factor makes some people keep longer telomeres and also drives them to exercise. But another study by German researchers from the University of Saarland suggests that this isn’t likely. Like the Colorado study, the Saarland study found that older runners and triathletes had telomeres almost as long as younger subjects, while older non-exercisers had much