5 Reasons Why You Get Tired During Your Workout (And How to Fix It)

You walk into the gym ready to give it your all, but after twenty minutes you feel like you’ve run a marathon. Your muscles ache, your breathing is off, and excuses start playing in your head: “Maybe today’s just not my day.”

You walk into the gym ready to give it your all, but after twenty minutes you feel like you’ve run a marathon. Your muscles ache, your breathing is off, and excuses start playing in your head: “Maybe today’s just not my day.” If that sounds familiar, you’re not alone. But fatigue during a workout isn’t always a sign you’ve pushed yourself to the limit. Often, it’s a signal that you’re making some mistakes. Here are five common reasons why you get tired too soon—and how to fix them.

Training on an empty stomach

If you show up having only had coffee, don’t expect miracles. Without glycogen stores, your muscles tire quickly, energy fades, and every exercise feels like torture. Yes, training fasted can help burn fat, but only if you’re an experienced, well-prepared athlete. Otherwise, it’s a recipe for failure. Just a light snack before your workout—like a banana or yogurt—can make a big difference.

Starting too fast

Maximum weight, minimal rest, go! That’s not how it works. You don’t give your body time to warm up properly, your breathing gets off, your technique suffers, and after 10 minutes you’re wiped out. Follow this approach: warm up, gradually increase the load, keep a reasonable pace. That way your workout will be effective and safe.

Poor technique

You work hard but don’t see results? You might be doing exercises incorrectly—using momentum instead of muscles, “playing” with the weight instead of controlling the movement. The result is fatigue, pain, and no progress. Better to do fewer reps with good form.

Inadequate rest between sets

Rest according to your goal: for muscle growth, 60–90 seconds; for strength, up to 3 minutes; for endurance, less than a minute. If you rest too little, you won’t recover; too long and your muscles cool down. A timer and focus are your best friends.

Lack of periodization

Always going all out leads straight to overtraining. Muscles and your nervous system get tired, progress stalls. Mix light and moderate weeks, and give your body time to recover.