It's called the freshman five.
One of the first things anyone who works in Parliament learns when they arrive is that in the first year on the job, you put on 5kg.
Although there is a gym on the parliamentary precinct, the long hours and the temptation to constantly stress-snack often get the better of people.
That is doubly so for MPs and ministers. One scoffed at me when I explained the "freshman five" concept.
"It's more like the freshman 10," they said.
But there are a few battle-hardened fitness freaks who roam the halls of power, armed with sports shoes and yoga mats, determined to keep the freshman five, or 10, at bay.
I caught up with a few of the more active MPs to take me through their workouts.
Firstly, I turned to National.
In June, National deputy leader Paula Bennett received a text meant for someone else.
"Anyone for a slow run at 6:45am?" It was from Simon Bridges and was to fellow MPs Michael Woodhouse and Bennett.
But, as Bridges revealed in the text chain, the message was actually intended for Paul Goldsmith.
She tweeted the exchange. Months later, I had convinced the lads to let me join them for a run.
So, on a sunny Wellington morning, I joined the MPs for a light jog along the waterfront.
Woodhouse and Goldsmith put me to shame. Neither of them break a sweat over the six or so kilometres.
Bridges, on the other hand, not so much – but better than me.
"I don't want you writing a story about tubby Bridges lagging behind," he says to me at one point during the run.
At another point – maybe 4km in when I stop the group for a break – Bridges admits he is "dying inside", although I suspect he is just trying to make me feel better.
He says that in the earlier years of the trio's political career, they would all go running quite frequently.
Often, 10km to 15km across Wellington.
It's been a while since the three of them have done that, Bridges says.
"The burden of office has fallen upon us," Woodhouse says.
"For Simon in particular," Goldsmith adds, "he has great burdens to carry."
"The burden of the burgers," Bridges says.
"There are a few too many burgers hanging around the midriff."
The three MPs remain every part the politician even when they're out running; waving to passersby, saying hello to mothers with prams and groups of seniors on morning walks.
At one point, we walk past a group of school kids – "If you look to the right, you'll see the leader of the opposition, Simon Bridges," their teacher said.
Later, we run past the Spirit of Adventure ship, where Bridges yells some words of encouragement to the kids on board.
There is a lot of chatting during the run, mainly my probing questions, but also Bridges giving Goldsmith a good ribbing.
This, I assume, is because the day before, Goldsmith had remarked to a colleague of mine that Bridges "was not the man he used to be" when it comes to their runs.
We're coming to the end of the run, and Bridges sprints ahead, up the steps leading to Parliament's forecourt, to race Goldsmith. Bridges wins – I'm fairly sure Goldsmith let him.
Woodhouse and I hang back and watch the pair sprint up the stairs. "He'll pay for that in the morning," he says, gesturing to his leader's Achilles heel.
After we're done, I ask how everyone is feeling.
"Look, I think that was great," says an out-of-breath Bridges.
"A bit like the election cycle; reasonably slow start, a bit sluggish in the middle but we all came through quite strongly at the end."
Goldsmith is also still in MP mode.
"Very strong headwinds that we overcame."
Woodhouse, National's health spokesman, changes the narrative, but only slightly.
"I was a bit worried about you from a health perspective," he says to me. "We don't want you to be troubling the [health] system this week."
Bridges again: "There was one moment where you were keen to leap out onto the road and disobey the road rules," he says to me.
"My version of events is I basically saved your life."
Next on my list is Police Minister Stuart Nash – a frequent gym user and one of the only people in Parliament who uses the big weights.
He declined my offer to work out together.
So I decide to join Health Minister David Clark for a run instead.
He turns up with fellow minister Iain Lees-Galloway and Labour backbencher Jamie Strange.
As we were heading out, we walk past Finance Minister Grant Robertson.
"Come along!" I yell out.
"I forgot my gym gear," he jokes.
After a few light stretches, and a quick photo op, we are off.
Clark is in good shape and says he runs fairly regularly – just a few months ago he completed a marathon.
Strange, too, is an accomplished runner and Lees-Galloway – although more of a "rowing machine man" – is also in pretty good shape.
Lees-Galloway and Clark, as ministers, often face a barrage of questions from the opposition during question time.
They say they love the cut-and-thrust of it all and their minds are sharpened by a good run before going into the House.
Clark says he goes running once or twice a week when he's in Wellington.
He says when he first became a minister he saw how easy it would be to not look after himself, so he's tried to be as disciplined with his running as possible.
"I try to be as active as I can be; I want to lead by example as the Minister of Health."
Lees-Galloway takes a serious approach as well. "You've got to take care of your wellbeing; as ACC Minister and Workplace Health and Safety Minister, those are things we talk about a lot."
We run in silence for a few minutes before Lees-Galloway asks: "Where are we going?"
"I don't know," replies Clark, before asking me how far the Nats went.
"Roughly 6km," I reply.
"Good, let's go 10m further than that."
The Minister of yoga
Green MP and Minister for Women Julie Anne Genter is known around the traps as the "Minister of Yoga".
She's been doing it for more than 20 years and still continues to practice.
She likes how it can make her really "present and in the moment – not caught up in my thoughts".
While as a minister and a mother she doesn't get as much time for yoga as she used to, she still tries to get "a few poses in" as often as she can.
Her "studio" of choice these days is her ministerial office – it's there she has invited me to do some yoga with her.
I arrive at her office limbered up and ready to go.
But Genter is picky when it comes to the instructional video we're going to watch and she ends up searching for close to 15 minutes.
We finally settle on a video. A softly spoken American woman who, at multiple points instructs me to find my "inner self", appears on the screen.
We begin; slowly at first with easy poses like "downward dog" and "the cobra".
Then, it starts to get harder. Genter handles herself well – I do not.
I falter when it comes to the "Supported Pigeon" – better known as the "Eka pada svastikasana".
"Is this even close?" I pant.
"Ummm no." She tells me bluntly.
We try an easier pose – "good!" she says after I collapse into a defeated heap.
I think I'll stick to running.