How Long Should a Workout Last? The Truth About 45, 60, and 90 Minutes

Should you work out for 45, 60, or 90 minutes? The answer isn’t universal. The right duration depends on your fitness level, metabolism, energy reserves, and overall recovery.
A common belief is that workouts should end at 45 minutes to avoid muscle breakdown (catabolism). But in practice, if you’re well-fed and rested, your body can handle more — and benefit from it.
Pre- and post-workout nutrition is crucial. Ideally, you should eat 90 minutes before training and replenish with protein after. The energy you consume must align with what you burn during exercise.
Three key factors determine how long you should train:
• current energy levels;
• nervous system state (rest and recovery);
• metabolic rate.

Advanced athletes often train up to 90 minutes. That’s because anabolic hormones like growth hormone and testosterone peak within the first hour. After 90 minutes, catabolic hormones like cortisol may rise.
Break your session into:
• warm-up: 10–15 minutes;
• strength/core training: ~45 minutes;
• cardio/stretching: 20–30 minutes.

Beginners should stick to 60–90 minutes, while experienced lifters can adjust based on intensity, goals, and targeted muscle groups.