Dr Pat O'Callaghan only started smoking when he became a non-consultant hospital doctor. He knows of many other young hospital doctors who also smoke cigarettes and drink coffee as part of their battle to stay awake during the 32-hour shifts they regularly face.
A cardiac registrar in Adelaide and Meath Hospital, Tallaght, Pat has been helping co-ordinate strike coverage in the 464-bed hospital by non-consultant hospital doctors - still often pejoratively referred to as junior doctors.
While the acute hospital has been able to cope under the strain of the strike with its staff levels down to about a third of normal, Pat is worried about what emergencies the bank holiday weekend may bring.
On top of their already long hours, non-consultant hospital doctors have all this week had the additional stress of worrying that something catastrophic could occur at any time, he says.
"There's a fine line between control and out of control," says Pat, who has been qualified for five years and earns £27,000 annually before tax. Because the hospital's out-patient department and elective admissions have been cancelled, the day-time coverage is adequate, he says.
But after 5 p.m., when the number of doctors in the hospital drops by 90 per cent, stress levels rise. It is then, after most consultants have gone home and the nurses have ended their pickets, that the hospital doctors' worries really start.
"At the best of times it's really hard to work from 9 a.m. one morning to 6 p.m. the next day, but you do get used to it and things do work out. But because of the extra work during the strike things have been very difficult and the potential is there for things to become catastrophic.
"Everybody is working harder than they usually do and that's fine for a few days. As a group we don't have very many reserves anyway because we work so close to the bone. As the strike progresses we are just going to become more and more tired. It's when people become tired that mistakes are made."
The burden of duties normally carried out by nurses has been shouldered largely by non-consultant hospital doctors throughout the State. Pat says junior doctors in Tallaght have faced a steep learning curve this week in administering intravenous injections.
"It's been taking people so long to make up drugs because they are not used to doing it that everybody is working very slowly . . . the potential really is there for it to snowball. Our main concern is that as the strike goes on, the public will start returning in greater numbers."
The types of extra duties Pat had to do this week in the coronary care unit, which has high-dependency cardiac patients, includes clerical work such as ordering X-rays, hanging fluid drips and giving blood. He stressed the "huge sense of solidarity" with the nurses in the hospital, and emphasised the strong co-operation between nurses and medical staff.
He said any emergencies faced this week have been dealt with normally.
"We had a `crash call' this week, when a patient thought he was having a cardiac arrest. There was no mention by nurses of what duties they would do. The patient had to be resuscitated and it went like clockwork," he says.