Aerobics Turn Back the Clock
In 1966, researchers took five healthy 20-year-old men, tested their cardiovascular capacity, put them to bed for three weeks and retested their cardiovascular capacity. They then gave them eight weeks of intensive exercise training, and again measured their aerobic ability.
The result was the Dallas Bed Rest and Training Study, published in 1968. The study provided exercise researchers with in-depth information on how the body uses oxygen, how exercise--or lack of it--affects heart rate and on the body’s ability to use oxygen.
“It still remains one of the most important manuscripts in exercise science,” said Dr. Benjamin Levine, medical director of the Institute for Exercise and Environmental Medicine at Presbyterian Hospital in Dallas. Levine, along with three researchers from the original study, recently published a 30-year follow-up in the American Heart Assn. journal Circulation. They found all five men--now either 50 or 51--and again measured cardiovascular capacity. They then put them on a training program over six months and measured those results. Their findings for these men, who are typical of many middle-age Americans, are encouraging for couch potatoes who want to mend their ways.
In 1966, one of the participants was a semi-pro football player, another a long-distance runner and the other three were basically sedentary. Thirty years later, only one man, the runner, was exercising regularly--he was still running. The former semi-pro football player lifted weights fairly often, according to the study. Another, who had been inactive in his 20s, was last active about six months before the study using a stationary bicycle. The remaining two had not exercised regularly in years.
All five had gained weight: The average was a 30% increase in total body weight, most of which was due to an increase in body fat--from an average of 13.9% to 28%.
The study also looked at their maximal oxygen uptake, called VO2max, a measure of cardiovascular capacity or aerobic power, compared with 30 years ago.
One, who had not regularly exercised in more than 20 years, had a decline of 16% in VO2max. The second, the runner, showed a decline of 12%. The third, who had been inactive in 1966 but fairly active since, showed a 16% increase. The fourth, who hadn’t regularly exercised in three years, showed no change in VO2max. The fifth, the ex-football player, had a 27% decline. Yet what was remarkable, the researchers said, was that three weeks of bed rest in the first study had a more profound impact on the men’s cardiovascular power than 30 years of aging.
“Not a single man was less fit 30 years later than he was after three weeks’ bed rest. Bed rest is worse for the body.”
In part two of the study, the five men were put on an endurance training program.
None achieved the same VO2max they had after the intensive training in their 20s.
But, remarkably, all essentially reversed any age-related decline, the researchers concluded. That is, aerobically, they went back to their early 20s.
