Crux of Why most olympic records are broken in the afternoon: Your body’s best time for everything by Belle Beth Cooper:

Science has identified some activities work better at specific times during the day, including:

  • “we should try to get most of our calories earlier in the day, and have lighter, earlier evening meals when possible.”
  • Muscle strength and hand-eye coordination peak in the afternoon, so this is an optimal time for physical exercise.
  • Analytical work is best done in the morning, while creative work is better left for the late evening.