Sunday morning, 6.30 a.m.: Get up with the usual intense dread about the next two days. I'd rather do anything else. I make sure to get breakfast. Who knows when I'll get a chance to eat again? Cycle to the hospital.

7 a.m.: Arrive. I am the first doctor on call to care for about 250 patients through the weekend.

The pager starts going off. It keeps going off, at least every 15 minutes. There are lots of odd jobs to do which during the week would be done by phlebotomists, ECG technicians etc, such as taking blood, inserting IV drips and canulas. Throughout the morning I am reviewing patients, changing their management, carrying out medical investigations, admitting patients, liaising with more senior medical staff. Throughout the bleeper is going off, calling me to other parts of the hospital for jobs, and the corridors are long. I must walk, no, run, several miles a day.

The day is punctuated by headaches and dehydration. I keep thinking I must get something to drink. The hospital is very warm. The other problem is finding a moment to get to the bathroom.

7 p.m.: I think I must get something to eat and order an Indian takeaway for delivery - £12. Go to doctors' residence room and wolf it down while taking notes. I'm bleeped four times in that seven or eight minutes - twice for routine things that need to be charted, once for something else and once because a patient had become hyper-tensive. I leave my meal to deal with that, which takes about three-quarters of an hour. I don't get back to the food.

8 p.m.: Back to the grindstone. Things are taking longer to do. I have problems getting several IV drips in. Pressure is building all the time.

Monday morning, 1 a.m.: My cardiac arrest bleep goes off. It's very loud. I drop everything, there's a rush of adrenalin and I run as fast as I can. I am the first to the ward where an elderly lady has gone into arrest. I start cardio-pulmonary resuscitation. In seconds there are crowds of people, lots of voices. We lose her.

3 a.m.: I'm lonely, preoccupied with being tired and have an indescribable desire for bed.

4 a.m.: I try to get some sleep, but don't. The bleeper keeps going off, and, torturously, always when I'm reaching that twilight time before real sleep. You try to be polite but it does affect how you interact with colleagues.

6 a.m.: I am up.

9 a.m.: I meet with rest of the team for ward rounds. I'm groggy, too tired to even talk. We review 30 to 35 patients, order X-rays, cardiograms, CTs, bloodtests, send some to ICU. We admit pneumonias, strokes, ODs.

10 a.m.: Clinic starts.

1.30 p.m.: Clinic ends. I get 20 minutes for lunch - my first break with food since 7 p.m. last night.

Afternoon: Routine ward work; organising patients' needs; team meeting.

6.30 p.m.: Finish work. Cycle home. I feel terrible.

7 p.m.: Take a boil-in-the-bag meal from the freezer. Prepare it. Notice I have lost weight again. Think of how social life, old interests like sport and travel are passing me by.

8 p.m.: Fall into bed and asleep within minutes.

2 a.m.: Wake feeling very dehydrated.

8 a.m.: Get up. Feeling groggy. I never get restorative sleep. Cycle to the hospital. I will be on call again on Friday night.

Footnote: The junior doctor is planning to emigrate to the United States. "I don't see any future here," he says.