Outside, the Perthshire countryside is covered by an 18-inch deep blanket of snow, broken only by a couple of winding roads and the slate grey flow of the River Tay.
It is approaching midday, yet the 19-year-old has long since retreated indoors from the harsh conditions after completing a stint on the water. "Another hour in the bank," is how she describes the 6am session, one which could only begin after she had spent 40 minutes nursing her car along the eight miles of treacherous roads to the whitewater centre at Grandtully.
Some of her canoe slalom peers would surely have looked outside that morning and decided to delay their departure. Not Maslen, though. Not any more. "Mental maturity" is how she describes what has changed about her in recent months, a spell during which the responsibility of living on her own has been heightened by a need to combine training commitments with her studies in English and geography at the University of Stirling.
Having taken a year out after leaving Breadalbane Academy to concentrate on her sport full-time, Maslen was concerned about the effect a return to education last September would have. Yet it turns out she has learned more at university than she expected.
"Something has just clicked," she says. "Combining training with uni has helped me focus and I'm getting better quality in my sessions. I've realised that if I want to do something, I can, if I put the effort in and train smart enough, and that's not just in slalom. It's highlighted the myth of talent for me; the fact that it's about yourself and your training and nothing else."
That training is split in to what Maslen calls her "two worlds". Tuesday to Friday is spent in the central belt, living with her flatmates, working with a strength and conditioning coach at the Institute of Sport and training with coach Neil Caffrey in Alva, while the remaining few days of the week are dedicated to paddling on her home course at Grandtully.
Thankfully, the support of her parents and her inclusion on the Winning Students programme mitigates against the need to work but, between training, studying, writing for university newspaper Brig, spending time with her boyfriend and indulging in her twin passions of reading and baking, it is hard to see how she would find the time anyway. Even if she doesn't mind getting up at 6am.
"Not much of a student, am I?" she says, laughing. "I don't really have time to go to clubs and stuff but I've done it all before and I don't really miss it. I must admit, though, I do appreciate the days I get a lie in a lot more."
Such dedication might be demanding, but she is reaping the rewards. Currently on the cusp between the junior and senior ranks, Maslen made a significant statement of intent by finishing 12th in the full UK rankings last year and becoming Scottish under-23 champion, and she is determined to make an even bigger impact on the main circuit once this season begins in March.
British selection is her primary goal but, beyond that, Rio and the Olympics Games loom large. With that in mind, the next couple of years will be spent honing her technique. "I've developed this motivation tool where I make myself learn at least one new thing in every session, either about myself or my technique," she explains. "Until I've done that, I won't leave the water."
How things have changed. Having spent her formative years in Oxford, Maslen and her family moved to Havelock North, a small town in the Hawkes Bay region of New Zealand, before returning to set up home in Perthshire in 2005. Watersports had become part of her life during that stint in the Antipodes yet, when she joined the school canoeing club after a year in Scotland, the 13-year-old was far from convinced.
"My first thought was 'this is really unstable; I don't like this at all'," she recalls. "I was a water baby but slalom is one of these sports you have to work really hard at and, at that time, I wasn't big on working hard. Then I won a race . . ."
Her confidence swelled. Soon the tumultuous unpredictability of the water and capriciousness of the sport became familiar, comforting even. Maslen began to emerge as a genuine prospect, her slight figure belying the aggression and power essential to thrive amid the fierce waters. "The way I tend to describe it is that it's like being thrown down a flume, with things like rocks and a few steps added on the way down."
Fear is not something she allows to enter her mind. It would be nothing more, she insists, than a barrier to her ambitions. "I want to be on the British team; to medal at the Olympics; to become prestigious in the sport and my name to be known everywhere. Failing that, I quite fancy a job at the National Geographic."
n Amber Maslen is one of more than 150 talented athletes to gain support from Winning Students in 2012/13. The programme gives students the platform to perform in their sport and their studies.