Heavy vs. Light

Heavy vs. Light

The stimulus is different

After reading the subtitle of this blog, you may be thinking "Duh, I could have told you that."  Well, I read a lot to keep up with the fitness and wellness industry, and lately, I’ve come across a number of articles and blogs by reputable fitness experts saying that lifting light weights has the same effect as lifting heavy weights. 
One blog in particular (http://www.wellandgood.com/good-sweat/lighter-weights-just-as-effective-study/) caught my attention because it cites a certain study as supporting evidence.  This blog made similar claims:http://www.health.com/fitness/lighter-weight-more-reps
After reading the study and the blogs, I can’t hold it in any longer – it’s misleading and inaccurate to say what they’re saying, and I’m here to set the record straight:

  1. The study doesn’t state any specifics on loads and volume, and it doesn’t objectively measure intensity or fatigue in any way, shape or form. 


  1. The post study biomarkers of muscle biopsy and blood sampling show no change and no difference between the two groups -- the light-lifting and heavy-lifting groups.  Either way, over the course of time, if trained correctly, both groups should have seen a change and not necessarily the same type of change.


  1. The study states “fatigue is the great equalizer.”  So if you have the strength to use 50-pound dumb bells, don’t bother – use 25-pound dumb bells instead – you’ll be here till tomorrow cranking out chest presses, but no worries, you’ll get the same result, as long as you’re “fatigued”.   Wrong.  

To say that lifting heavy and lifting light accomplish the same thing just isn’t true.  Lifting heavy increases bone density, enables you to burn more calories while at rest (after the workout is over), increases human growth hormone production and helps with insulin sensitivity.  Lifting lighter weights builds endurance and burns calories (but once the workout is over, you stop burning calories at the same level).   Simply working till you’re fatigued, measuredsubjectively, will have a different impact on different people, and in some instances, will have no impact at all.  
So, for the record (again), lifting heavy loads is beneficial and won’t make you big and bulky.  Lifting heavier loads drives some of the most significant changes in our bodies.
Please note: I do not advocate lifting heavy loads at the expense of good form or if there are other circumstances that prevent you from lifting heavy loads, such as an injury.  Moving safely is of paramount importance.  I also do not advocate believing in fitness mythology, and heavy = light = myth.  Citing a study doesn’t make an assertion true.