Nearly half of doctors would not recommend their profession, research suggests.
It comes as thousands of junior doctors start their new jobs today - a day known as ''black Wednesday'' in the past because of higher death rates among patients.
A total of 44% of doctors said they would not recommend their profession, compared with 30% last year, according to the research from Wesleyan, the specialist financial services provider for doctors.
But it found doctors are still more likely to recommend their career than other professionals.
Over half (55%) of teachers would not recommend a career in the classroom, while 50% of dentists and 48% of lawyers take the same view of their profession.
The number of doctors who would not choose the same career if they could start again has risen to a third (33%) compared with 25% last year.
Increased workload and stress were cited as the main factors.
Nineteen out of 20 doctors said increased pressure caused by changes in the profession was a major cause of concern, with more than half (56%) of those saying they felt permanently under pressure.
When asked what they were most concerned about over the next five years, NHS funding emerged as the biggest worry for more than half (51%).
Changes to the NHS Pension Scheme and possible privatisation were also highlighted as major issues by just under two fifths (39%), while 13% raised concerns over consolidation of services in the NHS.
Three-quarters of doctors felt that the increasing cost of education and training, along with changes to pay and conditions, will mean future generations will be put off entering the profession.
Martin Bircher, a consultant orthopaedic surgeon and member of Wesleyan's advisory board, said: "The planned changes to the NHS, such as the new NHS seven-day service contracts for both hospital doctors and GPs, do have some merits in terms of the potential to improve patient care.
"However, there will inevitably be significant resource issues and they appear unlikely to ease the already heavy demands placed on medical professionals.
"Despite these challenges, being a doctor remains a hugely rewarding profession. A desire to care for others is what makes people want to become a doctor and being able to put this into practice every day is a privilege.
"That is why the majority of doctors in this survey say they would choose the same career again if they were at the beginning of their professional life."