They have worked almost flat out through a pandemic that, over 18 months later, continues to have a huge impact on their daily working lives.
Coronavirus elevated NHS staff to hero status in the eyes of many and, albeit through unprecedented and often tragic circumstances, demonstrated the sheer strength of their resolve when caring for people in desperate need.
However, as they continue to work through what is - hopefully - a once-in-a-century event, it is unsurprising that many are beginning to feel the strain.
Talk to many NHS staff working on the frontline and you will hear testimonies of tiredness and struggle. Although there does remain a distinct determination to press ahead and keep going, whatever lies ahead.
ITV Cymru Wales recently spent the day filming with three key frontline hospital staff at Ysbyty Gwynedd in Bangor, to hear of their personal accounts and insights into what life is really like inside the NHS.
Sister nurse Linda Rycroft carries a tragic personal memory with her every day of her working life.
Eighteen years ago she lost her mother in distressing circumstances.
Needing immediate medical assistance, an ambulance had been called for her. However, with ambulances being stuck outside a hospital, Linda's mother did not receive the treatment she needed in time.
"I live every day of my life with the consequences of a family member being at home, needing an ambulance and that ambulance gridlocked outside of a hospital," she explains.
"Eighteen years ago I lost my mum, she was in her early fifties, at home through an asthma attack. The ambulance didn't arrive because it was outside a hospital."
Linda now finds herself in the position where she is often the one allowing ambulances to offload their patients, freeing them up again to respond to other calls, or, asking them to wait as there are no available beds inside the hospital.
She said she is often reminded of that tragic event when making those decisions.
"It's very difficult now for me because I am that person making that decision to keep that vehicle outside now. So I can put myself in the position of that family member, of that patient," she said.
"You don't know what's outside in the community and we have to be mindful of that when we are holding ambulances."
Linda's role is crucial in the running of Ysbyty Gwynedd.
A senior sister in the emergency department, she is responsible for overseeing the allocation of staff, working closely with consultants, deciding where patients go for their treatment and helping oversee developing situations in each area of the emergency department.
Having worked for the NHS since 2006 it is clear Linda has a passion and a drive for what she does.
"It's the excitement, there is still excitement, you don't know what's coming through the doors," she says.
"You live on your nerves some shifts and you think 'I don't know how I’ve got through it.'
"We're a good team and we look after each other. You know that your colleagues have your back and, while it's physically and mentally challenging when you are flagging, you look at your colleagues that are still running around and they've got three kids at home and they've been up all night with them.
"I feel very proud of them and I think 'I can't flag because, god they are twenty years older than me with three kids, I go home to a dog.'"
Although sheer passion for the job alone is not enough to fuel the frontline staff through the constant daily battles they face.
Having worked through a crisis akin to a time of war, Linda has witnessed some of her most resolute colleagues begin to show signs of strain.
The staff are at the end of an 18 month period where I think they're now starting to become exhausted," she said.
"We're pretty stoic as a group of nurses, emergency department nurses. We do just get on with it, it is what it is, it's our choice to be here in an environment that you don't know what's going to come through the door and you can never close your doors.
"However, I think even the most stoic nurses amongst us are starting to feel the pressure now.
And, feeling that sense of strain herself, Linda has begun to have doubts over her long-term future working in the NHS.
Asked if she sees herself finishing her long career with the health service, she says: "For the first time ever, I think this year I've re-evaluated things.
"I don't know. I think in the next 12 months I'll see. There are going to be big changes post-pandemic, I think this [pressure] is going to be the new norm.
"We're going to have to live with this virus on top of everything else that comes in."
Dr Pete Williams has been working in the NHS for over two decades.
A consultant in emergency medicine and paediatric emergency medicine, Dr Williams works to ensure patients receive the appropriate treatment they need.
He also works with the Wales Air Ambulance.
Similarly to nurse Linda, Dr Williams displays a noticeable passion for his work and a strong desire to help people in their time of need.
"I've been doing this job for over 20 years," he says, smiling through his face mask.
"It's amazing. We see people on their best day and their worst day. We might not be the fastest but, when you need medical help, people know that the emergency department is there for them.
"Local communities expect to have - and deserve to have - emergency treatment available when they need it and that's what we're here for.”
With the NHS under immense pressure, Dr Williams' ambition to help everyone who presents at the emergency department is constrained by the reality of the situation on the frontline.
That, he says, can be an incredibly frustrating and disappointing aspect of his working life.
Speaking to ITV Cymru Wales, at a time when the hospital's emergency department was at capacity, Dr Williams explained how he was unable to provide the level of care he wanted to.
"We're finishing the shift with a department that is full. There is no capacity in any areas of the department," he says.
"I've got six ambulances waiting outside. The longest has been there for just under three hours and the longest wait for a hospital bed is two days and three hours.
"It's really disheartening because this isn't the care we want to give or that our patients deserve.
"It's demoralising for the staff because this isn't why people come to work, to work in these conditions and have people wait long and for excessive amounts [of time].
The hospital staff do continue to try their best though, something Dr Williams says fills him with pride.
"The staff turn in, they attend and with good spirits," he says.
"They're still trying to do their best.
"I'm a little bit awestruck by the staff who keep turning up for work, day in, day out, but not just turning up for work but turning up for work with smiles and determined to do a good job in the face of adversity."
Bethan Bee is the hospital's bed manager, or clinical site manager to use the proper title, who helps sort out the allocation of the beds as well as patient discharges.
At night Bethan is usually the most senior member of staff on shift.
Life may have been incredibly tough for Bethan and her colleagues recently, but she predicts the challenges will only grow in the weeks to come.
"Winter's in front of us now, we are bracing ourselves," she says.
"It is going to be busier than ever, we've got covid on top of it. Coming to work is quite challenging at times but it's the career we’ve chosen and the job is interesting and varied, so I do enjoy the role."
With everything that has happened in the last 18 months - and even further beyond - does she ever regret choosing a life in the health service?
"No I don't regret it, I don’t know what else I'd do to be honest," she explains.
"I've always been a nurse. This is what I've done since I was 18."
From speaking to all three of the frontline staff, a consistent theme that emerges is that it's often a sense of team spirit that is holding things together.
Bethan believes it is holding up, for now, but that things as they stand are simply not sustainable.
"They are long days on shift, they are nursing shifts - 12 hour shifts - so we often don't get home on time," she says.
"I stayed on til midnight one night just to try and help my colleague because I couldn't just leave her with the pressures there were on site.
"Walking around, you can see the staff are tired. They're exhausted from this continuous pressure really.
"I think they're feeling it mentally as well now on the wards. They're not able to deliver the care they want to deliver. They don't want patients in ambulances outside but it's inevitably what's happening because of the delays."
"I don't think it's sustainable. I think there's a lot of goodwill that goes on here.
"It's a challenge everyday and I don't know how long people can carry on with this."
Eluned Morgan, the minister for health and social services, said she believed the issues facing the NHS will be resolved and that the Welsh Government was working hard to assist those working on the frontline.
She said: "There is a short term issue here that we've got to address, which is the here and now and how do we get through this winter?
"There's a longer term issue, which is how do we address the backlog and people who are, frankly, suffering in pain and that’s the last thing I want to see as a health minister.
"We've got to stand by these people and get them through and seen as soon as we possibly can.
"And then there's the longer term issue, but we can start that now and that is how we all take more responsibility for our own health, how do we make sure we're fit, how do we make sure that we eat healthily, how do we make sure that we’re really trying to take responsibility ourselves for our own health?
"And it's really important that we don’t forget that there's a mental health issue that we need to address here as well, which we're very focused on at the same time.
"I'm absolutely confident that the amazing workers in the NHS that have managed to really keep it together right through the pandemic will continue to serve us, the people of Wales, in the way they have done over the past couple of years and I’m confident that we will get through this winter."
You can watch Wales This Week: Inside the NHS on ITV Cymru Wales on Monday 22 November at 8pm. The programme will also be available online after its transmission.