We’ve all been there: feeling physically drained during a workout, your muscles heavy and your energy completely zapped. Yet, somehow, when you think you can’t push any further, you manage to hit a personal best or finish a tough set. How is it that, even when you feel completely exhausted, you’re able to push yourself further than expected? Why do some people seem to have more mental endurance than others when it comes to training?

The answer lies in how your mind and body interact during exercise. When you work out, your body releases dopamine, a neurotransmitter that boosts focus, energy, and mood. This “reward” chemical makes us feel more alert and energized, helping us power through tough physical tasks. At the same time, serotonin is also released, which regulates mood and can cause feelings of relaxation and fatigue when it’s out of balance.

When dopamine and serotonin are in harmony, everything feels right. You’re focused, energized, and ready to tackle whatever your training demands. But as you push yourself harder, your body starts to deplete glycogen, the primary fuel source in your brain. This decrease in glycogen leads to a drop in dopamine levels, while serotonin levels continue to rise, resulting in feelings of fatigue, decreased focus, and a lack of energy. You start questioning if you can continue and may even experience physical symptoms like shaky hands or a sense of exhaustion.

However, it’s important to note that central nervous system (CNS) fatigue, a deeper level of exhaustion, is much more complicated than just a couple of tough hours in the gym. CNS fatigue takes a lot more stress to develop. So, when you feel like your nervous system is shutting down, it might just be your mind telling you that you’ve reached your limit, even though you haven’t.

In some cases, your brain might even interpret physical sensations, like trembling or weakness, as a sign that your CNS is overworked. But these symptoms can also be signs of lowered blood glucose levels, or simply the result of your serotonin and dopamine being out of balance. This is why stress, both mental and physical, can feel draining and lead to a reduction in glycogen in the brain. People often find it harder to train after a long day at work because of this energy depletion.

That’s where training your mind can make a big difference. Being able to conserve energy during your workout, knowing when to push hard and when to relax, is just as important as the physical training itself. A lot of athletes make the mistake of trying to amp themselves up between sets, often with loud music and aggressive behavior. This kind of high-energy approach may work in the short term, but over time, it can deplete your glycogen and imbalance your neurotransmitters, leaving you fatigued and less effective.

In contrast, taking a few minutes between sets to relax, focus on your breathing, and calm your mind can help rebalance your neurotransmitters, conserve energy, and improve performance over time. This approach helps activate your parasympathetic nervous system, promoting relaxation and recovery. It’s a simple but effective way to train smarter, not harder.

While getting hyped up for a big lift is important for some people, it’s crucial to save that intensity for the actual performance rather than during your entire workout. Try using more calming techniques during training and only turn up the intensity when it’s time to lift heavy. This approach will help preserve your mental and physical energy.

Even with this strategy, there will still be times when you feel tired or unmotivated. In these moments, it’s important to remind yourself that your mind is playing tricks on you. Push through those thoughts and stay focused on your goals. With practice, you’ll find that your mental toughness improves just like your physical strength.

Of course, there’s also a genetic component to how we react to stress and fatigue. Some people are naturally better at handling high-pressure situations, while others may struggle. However, this doesn’t mean that you can’t improve your mental resilience. Even if you’re not genetically predisposed to power through tough moments, with training and practice, you can still strengthen your mental endurance.

Exercise has already been shown to have positive effects on mood disorders, likely due to the brain chemicals that are released during physical activity. If we can train ourselves to relax and regulate our emotions during workouts, it could potentially lead to even better outcomes for managing mood disorders through exercise. This is still a hypothesis, but it seems like a plausible and effective strategy.

Ultimately, training is about more than just physical strength. The mental aspect plays a huge role in how well you perform. Your body is a complex system, and your mind is an integral part of how all these systems work together. Training your mental endurance can have just as significant an impact as building your muscles, leading to better overall performance and recovery.