Sometimes you feel like you’re on top of the world. Others, not so much. Training is most effective when the difficulty of your workout matches your ability on the day. This means you need a tool to measure your readiness. Enter Autoregulation. Rather than forcing yourself into a rigid percentage or predetermined load, autoregulation helps you adjust based on how you’re actually performing. It’s a tool that respects biology and helps us select the correct exercise intensity. Our bodies constantly adjust to internal and external pressures such as temperature, nutrition status and stress. Intuitively you know some days you “have it”, some days, you don’t. Autoregulation strategies such as Rate of Perceived Exertion (RPE), Repetitions in Reserve (RIR) and even bar speed allow us to select the correct intensity in real time and create more consistent, reliable progress.
In this article, we’ll walk through what exercise intensity actually means, how to measure it, and why the most effective intensity is the one that responds to your readiness on the day.
What is exercise intensity?
Exercise intensity refers to how hard you’re working relative to your maximum ability. Classically, intensity is thought of as a fixed load, such as 70% of your one-rep max. If someone could lift at most 100kg, 70% would be 70kg. The three major training variables intensity, volume and frequency all interact. For instance higher intensities or training loads means less volume. Higher volumes generally require lower intensities or loads. And frequency ties into both, as training more often spreads volume across the week. These basic principles underlie almost every effective training plan and help explain why intensity matters so much. However, we argue that intensity is better understood as how close you are to muscular failure. In other words, how close you are to the point where you can’t perform another rep with good form. Here’s what that looks like in practice.
Traditionally, many programs prescribe intensity as a percentage of your one-rep max. Something like “6 x 6 at 70%” looks clean on paper, but it assumes your one-rep max is stable. It isn’t. Strength fluctuates based on sleep, stress, nutrition, accumulated fatigue, technique sharpness, and even time of day. Percentages don’t capture that variability. Humans aren’t machines. This is where autoregulation steps in and helps you match the day’s training stimulus to how you’re actually performing.
How do we measure exercise intensity?
The most practical way to measure intensity is by using RPE or RIR, which describe how close you are to failure. An RPE 8, for example, generally corresponds to having about two reps left in the tank. This is also known as RIR 2. It is simple, scalable, and applies across exercises, rep ranges and training programs. RPE is not guesswork it’s a skill. With practice, people become surprisingly good at estimating how many reps they could still perform ¹, ². Bar speed, or how fast the weight moves, is another helpful clue. When you try to lift as quickly as possible, a natural “slowdown” occurs as you get closer to fatigue. This slowdown corresponds to what the research calls velocity loss, and keeping sets within roughly a 20–25% velocity loss tends to strike a sweet spot for strength and hypertrophy while avoiding excessive fatigue ².
RPE also integrates neatly into warm-ups. Treating warm-up sets like practice runs for your working sets helps you find the right load for the day. For instance, if your goal is 3 x 6 at RPE 7, you can ramp up with sets of six, building toward a final “indicator set.” If that indicator set feels like an RPE 6, you can increase slightly for your working sets. If it already feels like an RPE 7, congratulations, that becomes your first working set. Autoregulation also helps you adjust on the fly. RPE simply gives you a language to recognise training readiness moments and adjust. And if you’re unsure about your RPE? An occasional AMRAP (as many reps as possible) set can recalibrate your internal meter. If you thought you were lifting at RPE 8 but manage four or five more reps, that tells you something important about your training accuracy.
What is the best exercise intensity?
The “best” intensity isn’t a fixed number or magical percentage. Instead it’s the one that delivers the intended stimulus for you on that day. General resistance training guidelines suggest using “moderate or greater” (65% +) intensities and training major muscle groups multiple times per week ⁵, ⁶. Those guidelines are a great starting point, but they don’t tell you how hard you personally should push on a Wednesday when you’ve slept badly, or on a day when everything feels light and fast. Using RPE or RIR helps you consistently achieve the training intent even when life varies. Aiming for a target RPE 7 or 8 for most working sets keeps you in that “Goldilocks zone” where the training is challenging enough to stimulate progress but not so hard that it derails recovery. For beginners and experienced lifters alike, this range tends to support long-term progress because it balances stimulus and fatigue.
Autoregulation also plays a key role when starting a new program. Low-stress weeks, lighter average RPEs, and ascending sets (small increases in load each set) all help you find your true training baseline without overshooting. Once you know what your RPE 7 or 8 feels like, progression becomes clearer and more repeatable. Most importantly, autoregulation ensures that progress is defined by actual improvements in capacity, not just heavier numbers. If you add weight to the bar but the same set suddenly feels like an RPE 9 instead of 8, you’ve lost reps, or speed grinds to a halt, that’s not progress, you’ve just moved the goalposts and pushed relatively harder.
Final thoughts
Autoregulation isn’t complicated. It’s simply paying attention to how hard you’re working and adjusting accordingly. Tools like RPE, RIR and bar speed help us express intensity in a meaningful way and make training more consistent. They help you avoid both common pitfalls: not pushing hard enough and pushing too hard too often. You can’t control how you feel every day, but you can control how you respond to it. That’s the secret to effective training. If you’d like to learn more about effective training and how to employ autoregulation strategies for the best results, our team of expert coaches are here to help. Contact us today.
References
- The Effect of Load and Volume Autoregulation on Muscular Strength and Hypertrophy: A Systematic Review and Meta-Analysis – PMC (nih.gov)
- Methods for Regulating and Monitoring Resistance Training – PMC (nih.gov)
- Novel Resistance Training-Specific Rating of Perceived Exertion Scale Measuring Repetitions in Reserve – PubMed (nih.gov)
- Physical activity (who.int)
- ACSM Guidelines for Strength Training | Featured Download
- AUSactive-Exercise-Guidelines-Resistance-Exercise-Prescriptions-for-Healthy-Adults.pdf