Cardio: Why it Should be a Foundational, Rather than Supplemental Part of Your Training.

The common view of cardio and endurance training is that it is a fat loss tool.  It is a necessary evil that you force yourself to do in order to lose weight.  You don’t enjoy it, and you certainly don’t view it as a foundational component of your training regimen.  

Cardio sessions are often long, repetitive, and to many people, boring.  And with a set amount of time to invest into exercise in the first place, cardio is often jettisoned in order to get your resistance training session done. After all, resistance training builds muscle and burns fat accomplishing the proverbial killing of two birds with one stone.

But a groundbreaking new study on exercise shows that cardio is much more than just a fat loss tool.  In fact, the researchers found that endurance training activates powerful anti aging and longevity genes that resistance training does not.

The Study

In the study, the largest of its kind to date, researchers compared the effects of various forms of exercise.  Researchers split a group of 266 in active but healthy subjects into four groups.  

The first group:  Performed no exercise and served as the control group.

The other three groups performed three 45 minute exercise sessions per week 

The second group: Performed steady state cardio.  This group jogged at 60% of max intensity 

The third group: Performed interval training. This consisted of a warm up, then 4 minutes at 80-90% max heart rate (high intensity) followed by 3 minutes at 60-70% of max heart rate (low intensity).  This cycle was repeated three times after which the group finished with a cool down. 

The fourth group: Performed strength training only.  The regimen consisted of eight basic exercises on machines - the leg press, the leg extension, the leg curl, the seated row, the chest press, the pull down, the hyper-extension and the crunch. The subjects did 2 sets of 16-20 reps of each exercise at the individuals 20 rep max. 

The study lasted 6 months, with blood work being drawn at the start of as well as at the 6 month mark. The scientist then analyzed the blood of the subjects in each group and compared telomere length in the DNA of the cells in those samples. The faster you age, the shorter your telomeres become.  Engaging in healthy lifestyle factors can activate telomerase, an enzyme which  works to increase telomere length

Study Results 

Much to the researchers surprise, Strength training had no effect on the telomere length.  Both steady state and interval forms of endurance training did however lengthen telomere length in the blood cells.  The scientists concluded that endurance training, but not strength training makes the telomerase enzyme more active.

All three training modalities increased the production of nitric oxide in the blood stream as well as increased VO2max (maximal oxygen uptake), with endurance training leading to a much larger increase than resistance training.  VO2max positively correlated with increased telomere length, the greater the VO2 max, the greater the increase in telomere length. 

Interestingly, While significant increases in telomere length were seen in both steady state and interval endurance training, slightly longer telomere length was seen in group 2, the steady state group. 

According to study first author Christian Werner, “Our data support the European Society of Cardiology’s current guideline recommendations that resistance exercise should be complementary to endurance training rather than a substitute.”

Werner further states “From an evolutionary perspective, endurance and high intensity training may mimic the advantageous traveling and fight or flight behavior of our ancestors better than strength training.” 

The take home

Both resistance and endurance training have serious health benefits, both overlapping and individual.  Because of this, both modes of training should be foundational to your program.  

With that said, it may be worth noting the intensity of the resistance training in the study. The sessions took 45 minutes for the completion of two sets of 8 exercises.  45 minutes of exercise divided by 16 working sets leaves an average of 2.81 minutes to complete each set.  

With each set being 16 to 20 reps, the participants likely rested a full 2 minutes between sets limiting the intensity of the workouts.  

A more intense pace, for example only 60 seconds rest between sets, would likely have led to larger increases in VO2 max, and therefore telomere length. 

In addition, all of the exercises were done on machines that are by default lower intensity than the same exercise performed via free weight, much less a larger, compound lift such as a standard squat rather than a leg curl or extension.  

Increasing your resistance training intensity via shorter rest intervals, and performing more taxing compound resistance exercises may be an effective way to increase the telomere lengthening benefits of your resistance training. (In effect, you make your resistance training a form of high intensity interval training.)

Regardless, this study highlights potent anti-aging benefits to endurance and high intensity interval training, giving us reason to look at endurance training as more than a chore that we do to lose weight, but rather a foundational piece or our training regimens.

Differential effects of endurance, interval, and resistance training on telomerase activity and telomere length in a randomized, controlled study