Index
Morning or evening — science has a clear position, but one factor overrides everything, and most people ignore it.
What Circadian Rhythm Science Says
For afternoon/evening training (4-8pm):
- Core body temperature peaks, improving nerve conductivity and muscle elasticity
- Testosterone levels hit their second daily peak between 5-7pm
- Maximum strength and power are 3-8% higher vs morning
- Better reaction time and coordination
For morning training:
- Morning cortisol helps mobilize energy for high-intensity sessions
- Adherence studies consistently show morning trainers are more consistent long-term
- Morning training positively affects that night's sleep
The Factor That Overrides Everything: Consistency
Here's the uncomfortable truth: the difference between morning and afternoon training is statistically insignificant compared to the difference between training consistently vs. irregularly.
A 2019 meta-analysis found time of day explains less than 2% of variance in strength gains. Frequency, volume, and intensity explained the rest.
The best time to train is the time that lets you do it every day.
The Streak Test
In your Reppy Dashboard, you can see exactly which time slot has the most completed sessions. That's your personal optimal window — not what a lab study dictates, but what works for your real life.
Practical Recommendations
Morning person (6-9am): Warm up for at least 10 minutes. Slightly lower max strength, but the consistency you'll gain outweighs it.
Afternoon person (5-8pm): Your golden window. Better strength, coordination, and warmer muscles.
Irregular schedule: Always prioritize consistency over timing. A session at 7am or 10pm beats not training.
Your END attribute in Reppy scales with temporal consistency. Every day you log a session — whatever the time — adds to your streak and RPG progression. The question isn't what's the best time. It's what time can you do it every day.