1041 GMT February 19, 2019
In a study published in the European Heart Journal, researchers in Germany looked at the effects of three types of exercise – endurance training, high intensity interval training and resistance training – on the way cells in the human body age, and they found that endurance and high intensity training both slowed or even reversed cellular aging, but that resistance training did not.
Our DNA is organized into chromosomes in all the cells in our bodies. At the end of each chromosome is a repetitive DNA sequence, called a telomere, that caps the chromosome and protects its ends from deteriorating. As we grow older, the telomeres shorten and this is an important molecular mechanism for cell aging, which eventually leads to cell death when the telomere are no longer able to protect the chromosomal DNA. The process of telomere shortening is regulated by several proteins. Among them is the enzyme telomerase that is able to counteract the shortening process and can even add length to the telomeres.
The researchers led by Professor Ulrich Laufs, of Leipzig University, Germany, enrolled 266 young, healthy but previously inactive volunteers and randomized them to six months of endurance training (continuous running), high intensity interval training (warm-up, followed by four bouts of high intensity running alternating with slower running, and then a final cool down of slower running), resistance training (circuit training on eight machines, including back extension, crunch, pulldown, seated rowing, seated leg curl and extension, seated chest press and lying leg press), or to an unchanged lifestyle (the control group).
The participants who were randomised to the three forms of exercise undertook three 45-minutes sessions a week, and a total of 124 completed the study. The researchers analyzed telomere length and telomerase activity in white blood cells in blood taken from the volunteers at the start of the study, and two to seven days after the final bout of exercise six months later.