Cardio boosts metabolism more than strength training, study claims

When it comes to the world of exercise, no debate is as contentious as cardio vs strength training.

While some fitness aficionados will happily endure hour-long slogs on the treadmill, others will turn their noses up at anything cardiovascular, choosing instead to spend their workout time lifting heavy weights and ‘getting their pump on’.

As for which form of training is superior, there is no clear winner as this largely depends on your fitness goals and basic preferences.

However, despite claims that strength training burns more calories than its cardio counterpart, a new study has revealed that cardio training may offer more benefits in terms of metabolism.

Researchers at the University of Copenhagen examined the differences between levels of hormone production after a group of participants completed both strength training and weight training programmes to see how they compared.

Published in the Journal of Clinical Investigation Insight, the study involved 10 healthy young men who were divided into two groups, completing either strength or weight training once a week.

Those doing cardio completed their exercise on a bicycle while those doing strength training did a weights-based programme consisting of five exercises, each of which had to be repeated 10 times, designed to work each of the major muscle groups such as the chest, biceps, triceps and quads.

After completing the workouts, which lasted 60 minutes each, blood samples were taken over a four-hour period to measure participants' levels of lactic acid, bile, blood sugar and the different levels of hormones in their body.

The analysis revealed that those who had been cycling experienced a significant increase in the production of the hormone FGF21, which offers numerous positive effects on one’s metabolism, the process by which our body converts food into energy.

Boosting one's metabolic rate can be beneficial because the higher your metabolism, the more calories you burn at rest, which can help promote weight loss.

Those who trained on the exercise bike had three times as large an increase in FGF21 production compared to those who did strength training, who experienced no particular changes with regards to production of that particular hormone.

“Of course it is very exciting for us researchers to see how different forms of physical activity actually affect the body differently,” comments co-author Christoffer Clemmensen, associate professor from the Novo Nordisk Foundation Center for Basic Metabolic Research.

“We have known about the effects of various forms of training on more well-known hormones like adrenalin and insulin for a long time, but the fact that strength training and cardio exercise affect FGF hormones differently is new to us,” he added.

Clemmensen explained that the results could be significant with regards to ongoing research into FGF21’s potential to be used as a drug to combat diabetes, obesity and other metabolic disorders.

“The fact that we are able to increase the production ourselves through training is interesting,” he concluded.