Trying To Build Muscle? Don't Overlook This Recovery Hormone

If you've started strength training recently, you've probably also started paying more attention to your protein, your workout split, and whether you're progressively lifting heavier. But what if you're still not seeing the progress you expected?

Most of us assume the answer is to work harder. Add another workout. Fine-tune our nutrition. Optimize our program. And while those things certainly matter, they aren't the whole story.

One of the biggest lessons I've learned from researching and writing about strength training is that we spend a lot of time talking about how to challenge our bodies, and not nearly enough time talking about whether our bodies are actually able to recover from that challenge. That's where stress enters the picture.

More specifically, cortisol.

The truth about cortisol & your workouts

Cortisol has become one of wellness's favorite villains, blamed for everything from stubborn belly fat to poor sleep. The reality is much more nuanced. Cortisol isn't inherently bad; in fact, you wouldn't survive without it. It's essential for waking you up in the morning, helping you perform during a workout, and responding to everyday challenges. The problem isn't cortisol itself. It's when your body rarely gets the chance to come back down from that heightened state.

If you're lifting consistently, eating enough protein, and still feeling like your progress has stalled, your nervous system may deserve just as much attention as your training program.

Cortisol isn't the enemy

Despite its reputation, cortisol is actually an incredibly helpful hormone.

Produced by your adrenal glands, cortisol is released whenever your body perceives a challenge, whether that's waking up in the morning, sprinting to catch a flight, giving a presentation, or squatting a heavy barbell. It helps mobilize stored energy, increases alertness, supports blood sugar regulation, and prepares your body to perform.

All this to say, you actually want cortisol to rise during a challenging workout. Exercise is a controlled stressor, and cortisol is part of the normal physiological response that allows you to meet that challenge.

Where things become more complicated is when that stress response never really switches off.

When healthy stress stops being helpful

Your body doesn't distinguish particularly well between different types of stress. A hard lifting session, five hours of sleep, a demanding job, relationship stress, under-eating, and scrolling emails late into the night all contribute to your overall stress load. Eventually, that cumulative burden can begin working against the very adaptations you're trying to create.

Ashley Damaj, BCBA, MSW, CN, CPT, sees this pattern often in clients who feel like they're doing everything "right."

"If you are sleeping five hours and your nervous system never downregulates, the macros are not the problem," Damaj says. "Your cortisol is working against the plan."

I love this perspective because it shifts the question from "What else should I be doing?" to "Is my body actually in a place where it can benefit from everything I'm already doing?" Strength training, eating enough protein, and progressively challenging your muscles are all important. But if your body is constantly operating in survival mode, it's much harder to recover, adapt, and ultimately see the results you're working for.

The gym is not where muscle is built

One of the biggest mindset shifts I've had around strength training was realizing that the gym isn't actually where muscle is built. It's where the process begins.

Every strength workout creates a small amount of stress. Muscle fibers experience microscopic damage, your nervous system is challenged, and your body receives the message: adapt so this feels easier next time.

The adaptation, the thing you're actually training for, doesn't happen while you're holding the dumbbell. It happens later.

Hours after your workout ends, your body gets to work repairing those muscle fibers, building new proteins, and strengthening the neural pathways that help you perform those movements more efficiently the next time around. That entire process depends on having enough protein, enough overall energy, adequate hydration, quality sleep, and a nervous system that isn't stuck in a constant state of fight-or-flight.

As Kristin McGee, nationally recognized yoga and Pilates teacher, explains, "Recovery is where the body actually adapts and gets stronger."

For years, many of us were taught that results come from doing more: one more workout, one more class, one more set, one more calorie burned. But strength training teaches a different lesson. Your body needs periods of challenge to become stronger, but it also needs periods of recovery to actually complete that process. Without both, the equation falls apart.

Your brain & nervous system are adapting, too

When we think about strength training, we usually picture muscles getting bigger. But some of the earliest adaptations happen in your nervous system.

In fact, one of the reasons beginners often get dramatically stronger in their first few weeks of lifting is that their brain is becoming better at recruiting muscle fibers and coordinating movement, not because they've suddenly built a huge amount of muscle.

At the same time, strength training stimulates the release of brain-derived neurotrophic factor (BDNF), a protein often referred to as "Miracle-Gro for the brain." BDNF plays a key role in neuroplasticity—your brain's ability to form new neural connections, learn new skills, strengthen existing pathways, and adapt over time.

But neuroplasticity, like muscle growth, requires recovery. Sleep is when many of those newly formed neural pathways become consolidated. If you're chronically stressed, under-sleeping, and never allowing your nervous system to fully downshift, you're potentially limiting both physical and neurological adaptation.

Signs your body may need more recovery (& not another workout) 

One difficult workout isn't going to derail your progress, and neither is one stressful week. The bigger concern is when stress becomes your baseline.

If you've been training consistently but feel like your body isn't responding the way it used to, it may be worth asking whether recovery, not effort, is the missing variable.

Some common signs include persistent soreness that never seems to fully resolve, declining performance in the gym, restless sleep, feeling unusually fatigued despite sleeping enough, nagging aches and pains, or a lack of motivation to train. 

None of these automatically mean cortisol is elevated, and they certainly aren't diagnostic on their own. But together, they can suggest that your body would benefit from more recovery rather than more intensity.

How to support healthy cortisol levels & better recovery

The goal isn't to eliminate stress. That's neither possible nor desirable. The goal is to create enough recovery that your body can adapt to the stress you're intentionally placing on it.

That starts with the fundamentals: prioritizing seven to nine hours of sleep whenever possible, eating enough overall energy and enough protein to support training, staying hydrated, and resisting the urge to treat rest days like something you have to earn. 

It also means making room for the habits that help your nervous system shift out of "go mode" and into recovery mode. A walk after dinner. A mobility session instead of another high-intensity workout. A few minutes of breathwork before bed. Even taking a moment to decompress after a workout before jumping back into emails or your to-do list can help signal to your body that the stressor has passed.

These habits may not feel as productive as squeezing in one more workout, but over time, they're what allow your body to actually benefit from the work you're already doing.

McGee encourages her clients to think of recovery as an active part of their training plan rather than something that happens by default. "Sleep, hydration, nourishment, mobility work, walking, breathwork, and restorative movement all matter," she says. "Recovery isn't being lazy—it's part of the training."

The takeaway

Wellness culture has conditioned many of us to believe that if we're not doing more, we're somehow falling behind. More workouts. More intensity. More discipline. More optimization.

Strength training has challenged that belief for me.

The goal isn't to accumulate as much stress as possible. It's to create just enough stress that your body has a reason to adapt, and then give it everything it needs to actually do that.

Sometimes that looks like lifting a little heavier. Sometimes it looks like eating another serving of protein. And sometimes, it looks like closing your laptop an hour earlier, taking the rest day, or going for a walk instead of squeezing in another HIIT class.

Because in the end, strength isn't just built through effort. It's built through the balance between challenge and recovery.