Why longer isn't automatically better
Beyond a certain point, workout effectiveness plateaus while fatigue and injury risk continue climbing — diminishing returns set in well before most people assume, particularly for strength-focused sessions.
A reasonable range for most training goals
45-75 minutes covers the vast majority of effective strength and combined training sessions, including a proper warm-up — sessions regularly extending well beyond this often reflect inefficient pacing rather than genuinely more productive training.
Quality over quantity as the real metric
A focused 40-minute session with minimal wasted time between sets typically produces better results than a distracted 90-minute session filled with long phone breaks and social chatting.
Adjusting duration based on the type of training
A quick HIIT session might be genuinely complete in 20 minutes; a longer, more traditional strength session might reasonably run 60-90 minutes — duration should reflect the training goal, not a fixed universal number.