If you only understand one thing about training, it should be the principle of progressive overload. There’s nothing more important in getting results from your training than this single principle. Progressive overload means gradually increasing your workload to stress the body more than it’s accustomed to. Not enough people incorporate progressive overload into their training, and I think it’s one of the biggest reasons that people fail to get results.
What is Progressive Overload?
Let’s start at the beginning (that’s how important this is!). When you exercise, you stress a lot of different systems within the body, including your central nervous, cardiorespiratory, energy, musculoskeletal, and thermoregulatory systems. Your heart and lungs work harder, increasing your heart rate and breathing rate, and your blood vessels constrict and relax, allowing more blood to be delivered to the exercising muscles. Your central nervous system (your brain and nerves) work to produce and transmit signals to the muscles, and process and respond to the many feedback signals coming back to the brain from the rest of the body. Molecules (phosphocreatine, carbohydrate, and fat) are broken down to provide fuel, creating byproducts in the process which need to be neutralized. Muscles, bones, and connective tissue experience large amounts of force and tension. Your body temperature rises and needs to be regulated through sweating. All of these things create stress.
The body doesn’t like stress. It likes to stay in homeostasis, which is a state of balance, or equilibrium, within the internal environment. Even when faced with external changes, the body will always adjust to return to homeostasis. It’s a safety mechanism. For example, you’re able to maintain an internal temperature of about 98.6 degrees Fahrenheit, no matter what the temperature is outside. That’s important because if your internal temperature gets too high, it can lead to serious consequences and even death. When you exercise, your homeostasis is challenged, and the body has to respond to keep functioning safely. So, when you consistently stress your body with exercise, it does something pretty amazing. It adapts so that the next time it experiences that same level of stress, it can handle it more easily.
There are many adaptations that are stimulated by exercise, including:
Neural: The brain sends stronger, faster, and more coordinated signals to the muscles so they can perform the movement more efficiently.
Musculoskeletal: Muscles get bigger, connective tissue (tendons and ligaments) get stronger, and bone density increases.
Cardiovascular: The heart becomes stronger and more efficient, blood vessels become more responsive to changing pressure, and blood volume increases so blood and nutrients are delivered more effectively throughout the body.
Metabolic: The processes that break down nutrients (carbohydrate and fat) become more efficient so the body can create energy to fuel the muscles faster and more easily.
These adaptations are the reason you train. They are how you get stronger, faster, increase your endurance, improve your body composition, decrease your risk of cardiovascular disease, etc. They increase your exercise performance, and they also benefit you when you’re not working out.
Muscle, as you may know, is a metabolically active tissue which means it uses energy all the time, even when you’re sitting on the couch. If you’re trying to lose weight, building muscle mass increases your metabolic rate so you’ll use more energy throughout the day. This contributes to a negative energy balance (using more calories than you take in) which is required for weight loss. A less well-known training adaptation is the increased ability of your body to use fat as a fuel as you get fitter (Talanian et al., 2007). Training for these adaptations is so much more effective than just trying to burn as many calories as possible in a workout, which is many people’s strategy (and it’s not a good one). Once you develop those adaptations, your body will be burning more calories and fat all the time. That’s much more likely to improve your body composition than just relying on a few hours of calorie-burning exercise a week to do the job.
Training adaptations are also important for preventing injury and disease and responding to unexpected external stress. Let’s say you’re completely inactive, and your body is not accustomed to exercise-related stress at all. One day you might suddenly find yourself sprinting for a bus or having to lift something very heavy. If you’re not adapted, there’s a chance that your body will suddenly experience stress well beyond its capability and something bad could happen. You could strain a muscle or tendon because it’s not used to withstanding a lot of force. You could have a cardiovascular event because your heart or blood vessels are not prepared to handle increased demands. I’m not saying that any of those things will happen, but I’d rather be prepared and confident that my body can handle a suddenly stressful situation. I like to think of this as emergency-proofing your body. I started thinking about that a few years ago when I was training a client who had one young child and was expecting his second. He wanted to increase his strength, and when I asked him why he told me that he wanted to be strong enough to carry both of his kids if there was ever an emergency. That’s obviously not the right motivation for everyone, but with that mindset he certainly did get strong.
Producing adaptations takes energy, and the body doesn’t like to use extra energy unless it has to (again, it likes to stay in a state of balance, and the more energy it uses the harder it has to work to maintain that balance), so it will only adapt if an adequate amount of stress is consistently applied. It’s a cost-benefit decision. If the amount of stress that’s being placed on the body is enough to warrant expending extra energy to build muscle, increase mitochondrial density, form more red blood cells, whatever it needs to do to prevent a serious disruption in homeostasis in the future, then it will invest that extra energy. If there’s not enough stress being regularly applied, then you won’t get those adaptations. How do you make sure your body gets the message that it’s worth it to adapt? You train regularly at a high enough intensity (heavy enough resistance, fast enough pace, etc.) to stress your body beyond what it can already handle. Using appropriate intensity is another important aspect of effective training that I’ll go into in detail in another article.
How Progressive Overload can help
We know that to get results from training, we need to stress the body past its current capabilities so it responds with adaptation. That’s where progressive overload comes in. You need to be aiming to do a little more, push a little harder, in each workout.
Here’s how simple it can be:
Step 1: Complete a workout.
Step 2: Record what you did (exercises, sets, reps, weight, pace, distance, etc.).
Step 3: Try to do more next time.
Of course, it’s a little more complicated than that, but honestly not that much more. Specifically, there are many ways you can incorporate progressive overload:
- Lift more weight for the same number of repetitions
- Lift the same weight for more repetitions
- Increase range of motion so your muscles have to work harder to complete a movement
- Increase cardio pace
- Increase cardio distance
- Decrease rest time between exercises
- Increase difficulty by moving to a more challenging exercise variation
But how do you know when to progress? And by how much? In part two of this article, I’ll spell out what I think is the simplest and most effective way to use progressive overload for resistance training: the repetition range.