"It's a rush and it's kind of addictive as well. You end up craving it. And once you get into the cycle of playing every night on tour, you start to operate at a different rhythm than you would at home. If I have a week off between shows I find it much more draining than doing it every night."
What Went Down builds on the hard-rocking-indie reputation the Oxford, UK, five-piece cemented in their first three albums, Antidotes, Total Life Forever and 2013's Holy Fire, which launched them into the big league and saw them filling stadiums and headlining festivals around the world.
Critics are already labelling it the band's most intense work yet and Philippakis agrees there is a primal nature to this album.
"The whole process of writing the record has definitely been an intense and private excavation. It's also a record that we've written very quickly so it's relied on instinctual decisions. We haven't had time to labour and explore every pathway. The process was governed by gut reaction to things, and that's what makes it primal."
He describes the songs as simplified, distilled versions of "something that could've been more elaborate and innate" had they worked longer on them. But rather they've let them sit as they are "much closer to their first expression", he says. And lyrically, they're not about "going to the disco on a Friday night" they're about "core, human concerns".
By that Philippakis, the son of a Greek father and a Jewish South African-born mother, is referring to themes of cultural identify, generational anxiety, heartbreak and insanity, admitting he did have to tap into his "inner madman" on this record.
But he does not want to romanticise the cliched notion that the best art comes from those in the depths of madness.
"I share a hesitancy about that word [madness] because I've been around real mental illness and it's not something that should be co-opted for a sound bite. But I do think you need to be able to push your mind into extreme focus. Or there needs to be some sort of drive that pushes you further."
And on this album, he says the band pushed themselves way beyond their comfort zones.
"There was a lot of blood-letting that went on; releasing things that were uncomfortable - definitely in the lyrics. A lot of it's very personal. Rather than just wanting to flatter yourself in a certain light, I think a lot of things are quite dark, and maybe unpleasant.
"So I definitely feel like there are things that we put ourselves through, whether imaginary or real, that we've gone to further lengths."
And you can hear that in the album's first two singles, the ferociously full-on title track and Mountain At My Gates, which harks back to the band's more melodic tunes like My Number, as it builds to an exhilarating climax of competing guitars and howls and yowls. The seething Snake Oil is another cracking tune.
There are gentler moments, too, like Give It All, and for that reason Philippakis implores fans to listen to the album in its entirety. "I want people to hear every song on the record. I always feel a bit weird that one or two songs represent the album because it can be misleading and it can be restraining because it only opens a narrow window into what is a bigger picture."
Philippakis prefers the more hectic songs when he's on stage but in the writing process, the more varied the better. "We'll write something on one day that's 150 BPM with like full-on guitars and screaming and then the next day [guitarist] Jimmy and I will go in sheepishly and write a love song on a Rhodes piano. That's naturally how it happens. The band's strength is being able to be ruthless and then tender on a dime."
And it's that dichotomy that really makes the Foals' sound as special as it is. It's also where Philippakis' strengths lie, even if it's not really how he originally saw his role in the band panning out.
"The way the band started, we were like a jam band playing at house parties. And I was much more interested in playing guitar and writing the instrumentation in a song than I was singing. I would kind of reluctantly come to the vocals and the lyrics towards the end of a song," he says.
"But as time has gone on, I've felt more confident and more comfortable with my voice and in allowing space to direct the songs. I feel like I'm a better singer now, and I invest a lot of my attention into how the words set the scene and how they communicate emotion."
For someone who doesn't overly enjoy promo, Philippakis is an incredibly chatty and engaging interviewee. And what is equally notable is that for someone who never wanted to be a singer, he's now hands-down one of the rock's most enigmatic and talented frontmen.
Foals' new album What Went Down is out now.
