Kirk said he knew about this from personal experience.
"I probably lived with quite a sore brain for many, many years and didn't do anything about it."
Kirk didn't realise he'd been "quite unwell for a while" until he finally addressed the issue.
He likened his condition to having a physical injury, but found that people tended not to treat their brains like a muscle.
"If I had a sore calf muscle and it was sore for more than three days I'd definitely be going straight to physio. But most people walk around with a sore brain for a few years and don't do anything about it."
"It's the most important muscle in our body and we need to treat it that way for sure."
However, despite the statistics, Kirk believed people were "on the right track" about accepting that mental illness was not a sign of weakness, and that the stigma attached to it wasn't so strong.
He noticed his friends, family and boss were more open about checking in and talking about how they were feeling.
Kirk said it was important to be honest in these conversations.
"My boss might ask me 'how are you going today?' and I'll say 'you know I'm actually feeling pretty average today'. Whereas five years ago I would had just said 'oh yeah, nah, I'm all good'".
"So I think we are getting better at just telling people that we're not feeling good – and there's nothing wrong with that."
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Main factors contributing to stress on-farm were, isolation, long hours, not enough time off-farm, poor eating habits and lack of sleep, Kirk found.
Physical exercise was helpful to combat stress, and Kirk had seen the positive effects of the Surfing for Farmers programme he'd been running in Raglan over summer.
"The farmers that are turning up…you should see how invigorated they are once they get out of the water. They are so happy, big smiles; they're like little children hyped up on lollies."
"It just shows that getting out in the fresh air, doing something different, getting your heart rate up is just so good for our brains."
For farmers, getting off-farm was "the key to making yourself feel better," Kirk said.
"It doesn't actually really matter what it is, but you just need an excuse that you put in your calendar once or twice a week, every week, and you make sure that you drive out the gate."
Where to get help:
Rural Support Trust: 0800 787 254
Lifeline: 0800 543 354 (available 24/7)
Suicide Crisis Helpline: 0508 828 865 (0508 TAUTOKO) (available 24/7)
Youthline: 0800 376 633
Kidsline: 0800 543 754 (available 24/7)
Whatsup: 0800 942 8787 (1pm to 11pm)
Depression helpline: 0800 111 757 (available 24/7)
If it is an emergency and you feel like you or someone else is at risk, call 111.