When it comes to the world of exercise, no debate is as contentious as cardio vs strength training. The Independent reports that 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, the report says despite claims that strength training burns more calories than its cardio counterpart, a 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.
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 report says 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.
The report says 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 Centre for Basic Metabolic Research in the report.
“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.
Background: Exercise has profound pleiotropic health benefits, yet the underlying mechanisms remain incompletely understood. Endocrine FGF21, bile acids (BAs), and BA-induced FGF19 have emerged as metabolic signaling molecules. Here, we investigated if dissimilar modes of exercise, resistance exercise (RE) and endurance exercise (EE), regulate plasma BAs, FGF19, and FGF21 in humans.
Methods: Ten healthy, moderately trained males were enrolled in a randomized crossover study of 1 hour of bicycling at 70% of VO2peak (EE) and 1 hour of high-volume RE. Hormones and metabolites were measured in venous blood and sampled before and after exercise and at 15, 30, 60, 90, 120, and 180 minutes after exercise.
Results: We observed exercise mode–specific changes in plasma concentrations of FGF19 and FGF21. Whereas FGF19 decreased following RE (P < 0.001), FGF21 increased in response to EE (P < 0.001). Total plasma BAs decreased exclusively following RE (P < 0.05), but the composition of BAs changed in response to both types of exercise. Notably, circulating levels of the potent TGR5 receptor agonist, lithocholic acid, increased with both types of exercise (P < 0.001).
Conclusion: his study reveals divergent effects of EE and RE on circulating concentrations of the BA species, FGF19, and FGF21. We identify temporal relationships between decreased BA and FGF19 following RE and a sharp disparity in FGF21 concentrations, with EE eliciting a clear increase parallel to that of glucagon.
Thomas Morville, Ronni E Sahl, Samuel AJ Trammell, Jens S Svenningsen, Matthew P Gillum, Jørn W Helge, Christoffer Clemmensen
[link url="https://www.independent.co.uk/life-style/health-and-families/cardio-strength-training-metabolism-effect-study-university-of-copenhagan-a8507641.html"]The Independent report[/link]
[link url="https://insight.jci.org/articles/view/122737"]Journal of Clinical Investigation Insight abstract[/link]