He went on to write that while his "fastest racing days" may be behind him, new challenges await, and that maintenance of a healthy, functional body and a calm open mind are of importance.
"Strength & mobility rank as highly as lactic threshold and Km splits once did," the actor wrote.
"Now, above all, I think of the lessons I will teach the little man. The example i set. The tools I equip him with for his journey," he said.
He added: "I’ve had my triumphs and failures in sport, career & life, but wading neck deep into the frothing wild water of life’s adventure, throwing myself wholeheartedly into everything I do has served me well.
"So onwards we go…" he penned.
The message comes shortly after it was announced that Sydney would be heading into four more weeks of lockdown restrictions, as COVID cases continue to rise.
Dan and Zoe welcomed their son Austin together in 2019, but did not publicly announce his birth until later on.
Late last year, the new parents shared their split on Instagram after five years of marriage, and have since been seen separately with their son on social media.
Revealing the news at the time, both stars wrote: “With the greatest respect for each other, Dan and I have separated."
They then went on to add: “Together, we will continue wholeheartedly to raise our beautiful boy Austin. He is, and will forever be, our greatest priority."