How to Tell If You’re Working Out Hard Enough

Learn how to know if you’re working out hard enough, and how your body should feel during and after exercise.

Ben Greenfield
6-minute read
Episode #20

Buy Now

As an Amazon Associate and a Bookshop.org Affiliate, QDT earns from qualifying purchases.

Several listeners and readers of the Get-Fit Guy have asked how to know if you’re actually working out hard enough, and this is actually a very important question – especially since I  recently opened the newspaper to see that an entire team of high school football players in Oregon wound up in the hospital after working out a bit too hard. But rather than scare you away from exercising by telling you horror stories about football players, this article will teach you how to know when your body has had enough exercise to get results, or when it needs more.

How Sore Should You Be After A Workout?

As you learned in “How To Build Muscle”, muscles tear when you exercise, and when given proper recovery, they bounce back stronger. While the word “tearing” may sound like a very bad thing, it is in fact quite normal, and the tiny micro tears that occur in a muscle fiber are nothing like tearing your hair out, tearing your eyes, or tearing your skin. Instead, these tears are completely necessary if you actually want to add lean muscle to either look better or boost your metabolism. However, if you do work out hard enough to actually stimulate these muscle advantages, the tearing does cause a little soreness. If there is absolutely no incidence of a little soreness, then you probably did not stimulate your muscles enough to get results.

Yes, that’s right, I said a little soreness. This is far different than being so sore that you are unable to move after a workout. If you can’t lift a fork to your mouth, turn the steering wheel on your car, or do the dishes, then you have gone too far with your muscle tearing. As a matter of fact, the medical term for excessive muscle tearing is “rhabdomyolysis” and this condition results in the release of muscle fiber contents (called myoglobin) into the bloodstream. This myoglobin is harmful to the kidney and results in kidney damage, extreme fatigue, intense joint and muscle pain, and seizures. Often, as in the case of the football players I mentioned earlier, it requires surgery to relieve the pressure from the excess inflammatory fluid build-up around the muscles.

In contrast, the best way to describe a little soreness that you’ll know it’s there, but it won’t be at the front of your mind. You won’t feel like punching a friend in the face if they touch a muscle you exercised the day before, and getting out of bed is not an extreme chore.

So here’s my quick and dirty tip for effectively working your muscles: follow the rule of three. If you can get to the goal number of repetitions for the exercise you are performing, and you can do three or more repetitions over and above your goal number, while still maintaining good form, then you should increase weight. If you cannot get within three repetitions without your eyeballs popping out of your head, you should decrease weight. This rule works very well for workouts in which you’re lifting a weight 10-15 times, which is the typical repetition range for most fitness routines.

Contrary to popular belief, while you’re weight training, your muscles burning doesn’t necessarily indicate that they’re being stimulated hard enough to cause tearing or soreness. Burning muscles are a result of lactic acid formation, and could indicate other things, like lack of respiration, or blood pooling in a muscle. As a matter of fact, try holding your breath while performing a weight lifting set and you’ll notice your muscles burn much sooner. This doesn’t mean you’re working out hard enough to get muscle-stimulating results. It just means your body isn’t getting a chance to blow off carbon dioxide, which is one of the primary ways to buffer lactic acid.

How Should You Feel During Cardio?

With all this talk about lactic acid and burning, it’s a perfect time to bring up how, you should feel during your cardio workouts. While lifting a weight heavy enough to cause muscle tearing and following the rule of three works well for most weight lifting workouts, aerobic exercise requires a different set of criteria. So here are three quick and dirty cardio tips to judge whether you’re working out hard enough:


All content here is for informational purposes only. This content does not replace the professional judgment of your own health provider. Please consult a licensed health professional for all individual questions and issues.

About the Author

Ben Greenfield

Ben Greenfield received bachelor’s and master’s degrees from University of Idaho in sports science and exercise physiology; personal training and strength and conditioning certifications from the National Strength and Conditioning Association (NSCA); a sports nutrition certification from the International Society of Sports Nutrition (ISSN), an advanced bicycle fitting certification from Serotta. He has over 11 years’ experience in coaching professional, collegiate, and recreational athletes from all sports, and as helped hundreds of clients achieve weight loss and fitness success.