NHS staff who've helped cared for the sickest coronavirus patients are paying the price with their own mental health - according to researchers.
Working in an intensive care ward, which is at capacity with critically ill patients, while wearing full PPE is physically exhausting.
But current and former ICU staff have told ITV News that the hardest part is seeing the effect on devastated families, unable to stay at their loved one's bedside.
"There were nights where you were tossing and turning because you're constantly thinking about patients, about their families who are worried sick about them" - Dr Laura Matheson recalls - "You come home from work very anxious, you go through periods of not being able to eat very well because your appetite goes."
ICU Staff reporting higher PTSD rates than army veterans
The very front of the NHS frontline has been the country's intensive care units, many of which have seen three huge surges over the past year.
It's meant staff are consistently working exceptionally hard - including many who volunteered to come in to the ICUs from other, quieter areas of healthcare. Researchers suggest that many may be suffering more than combat troops - according to an anonymous study of 709 doctors, nurses and other ICU staff.
Lead researcher Professor Greenberg said "Whilst these results are in some ways not surprising, they should serve as a stark reminder of the pressing need to protect the mental health of ICU workers now in order to ensure they can deliver vital care to those in need."
'I don't think this is over - it isn's for us'
But the demands being placed on frontline staff might be asked of them for a while yet.
With more than 600,000 people on the waiting list for surgey in the North West alone, the coronavirus catch up poses a major challenge.
Without sufficient rest and mental health support, the work force will not be in a position to deliver the volume of care needed - with the Intensive Care Society warning there may be high rates of early retirement and burnout.
Dr Shondipon Laha from the Intensive Care Society told ITV News that most ICUs are still not back down at their pre-pandemic levels of demand, and that staff will need rest before the catch up begins.
"The only way the public can really help by that is by following the rules and reducing the number of patients coming through - and when offered the vaccine, taking that up".
What help is out there?
The NHS has set up dozens of support hubs to help those "who have pushed their minds and bodies to the limit over the last year".
With £15 million of investment, the aim is to expand the psychological services available to NHS employees who are struggling with their mental health, and offer managers ways of supporting their entire team.
Dr May Sarsam is from the Cheshire and Merseyside Resilience Hub - which is for any NHS employee working in either area - and says the demand has been "enormous".
"What we want to try to do is ensure that there aren't any staff who are falling through the gaps, and to ensure that if there is a staff member who does needs something to help them to cope, and in order to help them manage at work and at home , that they have access to that, and that they have access to that at the right time."
Lynne Morgan, a District Nursing Team Leader at Mersey Care, approached the resilience hub after noticing a high level of staff sickness and anxiety among her team.