Based on the body’s ultradian rhythms that regulate wakefulness and focus (and even body temperature) — 30 minutes, 3 hours, and 11 hours after waking are optimal times for achievement oriented behaviors.

REF — Valdez P. Circadian Rhythms in Attention. Yale J Biol Med. 2019 Mar 25;92(1):81-92. PMID: 30923475; PMCID: PMC6430172.