Scientific Comparison: When Is It Better to Exercise and Why

The human body operates according to a 24-hour biological clock — the circadian rhythm. It regulates hormone release, body temperature, metabolism and muscle function.
Body temperature is lowest around 4–5 a.m. and highest around 16–18 h. Higher body temperature = better muscle elasticity, faster metabolism, better nerve conduction. Maximum athletic performance is achieved between 14–18 hours.
Testosterone: highest in the morning (6–9 a.m.), lowest in the evening. Cortisol: highest in the morning immediately after waking, decreases throughout the day. Growth Hormone: released in waves, with the largest wave during sleep.
A meta-analysis summarizing 26 studies. Conclusion: evening workouts are 3–8% more effective for strength, power and endurance indicators. Reason: higher body temperature, better neuromuscular coordination.
Morning workouts on an empty stomach may increase fat oxidation, but the overall calorie deficit is more important than the time of the workout.
Evening workouts can worsen sleep if performed less than 2 hours before sleep. However, if the workout ends 3+ hours before sleep, sleep quality improves.
Yes, if you recover. Professionals often train 2 times per day. For amateurs, one quality workout is enough.
There is evidence of 20–30% higher fat oxidation, but daily calorie deficit is more important. Do what is more convenient.
If you have no commitments, when do you naturally go to sleep? The MEQ questionnaire online can help determine it accurately.
Want to learn more? We recommend these sources:
📱 Apps: Strava, Nike Training Club, MyFitnessPal — track your progress and nutrition.
: Sports nutrition and training literature in Lithuanian and English.
🎓 Consultations: Consult a sports nutrition specialist or personal trainer for an individual plan.
⚠️ Important: All information is for informational purposes only. Before starting a new training or nutrition program, consult a doctor or a certified specialist.
In summary — the most important things are consistency and an individual approach. What works for one person may not suit another. Listen to your body, experiment, and discover what works best for you.
Remember that results don't come overnight — be patient and consistent. Good luck on your sports journey! 💪