But Hayden Breese's passion for taekwondo shows no sign of abating.
The 35-year-old Dunedin man has just completed his fifth dan black belt in a sport as equally demanding mentally as it is physically.
Breese said the fifth dan grading, which went for seven hours, required the mind to be in a "state of absolute belief" and the body to be "fine tuned".
"You can't allow for self doubt or distractions and you have to remain calm and focused."
Breese said this grading was "incredibly harder" than his previous four because he was busy running his own advertising agency, and he and his wife Samantha now have a 6-month-old son, Austen.
"I am incredibly proud of this grading given the time restraints I now have in life.
It was hugely rewarding and I was very tired at the end of it all."
There was no way he could have achieved his fifth dan without the support of his wife, he said.
"Without her understanding and encouragement it would not have been possible."
Breese's recent grading involved hours of self defence, theory, sparring, mastering the taekwondo patterns, as well as going over past techniques from previous gradings.
One of the hardest parts of the grading was breaking boards with a front kick while his eyes were blindfolded.
To pass the grade Breese had to achieve a 65% pass mark. He achieved 69%.
In the lead-up to his grading, Breese trained six days a week, sometimes twice a day, and lost 8kg in the process.
While thrilled with his accomplishment, he was nervously awaiting the results of two of his threshold club's students, Gena Salmon and Briar Topp, who graded for their first dan black belt at the same event in Rotorua.
"We will find out at the end of the week if they have passed and I think I am as nervous as them, but at the same time confident."
Breese is one of nine people nationwide and the only person in the South Island with a fifth degree black belt.
He first became interested in the sport at high school and has been passionate about it ever since.
"Taekwondo involves dedication, discipline, self control and helps to develop skills that can be transferred to other aspects of life, such as business and personal growth."
Breese had to wait four years to do his fifth dan. If he wanted to go for his sixth dan he would have to wait five years, and his seventh dan would take him six years.
" I haven't decided on that yet, but I could conceivably get to 47 and have my seventh dan."
While a lot of his time is dedicated to his business and his family, he also trains 50 members at his club, whose ages range from 5 to 50.
"I get great satisfaction out of helping kids find confidence, develop character and gain self control or an understanding of who they are."
Breese received his first black belt in 1996, second in 1999, third in 2003 and fourth in 2007.
Taekwondo black belts go up to ninth dan, but so far the highest achievement nationwide is seventh dan.
Earlier this year, he passed his examiners grade in taekwondo, making him the only examiner in the South Island.
He can now grade some of his students rather than them having to travel round the country to get graded.
It was quite common for students to overtake their trainers in terms of dans if they persevered in the sport, he said.
With a motto of "aim high and think big" he hopes to see many of his club members do just that.
