Background: Previous studies have shown a high incidence of both acute and post-traumatic stress among ambulance personnel. It has been shown that ambulance personnel are at a higher risk of being affected of heart disease, high blood pressure and cancer. Studies have also seen a higher incidence of substance abuse and suicide. One cause of these health problems can be work-related stress. No previous research has focused on the body's physical reactions in the form of changes in heart rate and stress hormones in ambulance personnel in connection with work-related stress. Nor is there any overall picture of what actually affects Swedish ambulance personnel in terms of reported morbidity.

Aim: The overall aim of the thesis is to investigate health problems in Swedish ambulance personnel and to study if there are any factors related to the work environment and the special conditions occurring in the prehospital environment that can be linked to the findings that appear.

The questions that should be answered are: Are there health problems that affect Swedish ambulance personnel to a higher extent than other professions in Sweden? Are there any factors relating to morbidity that can be linked to the profession and can be regarded as potentially dangerous? If so, are there methods to prevent health problems that can be implemented in daily work?

Methods: Studies I, II and III were all studies where stress markers (heart rate and cortisol levels) were measured during different conditions linked to the profession. Study I was a study where this was measured during physical exertion e.g. to carry a stretcher. Study II was a validated theoretical stress test to see how the ambulance personnel reacted to unknown factors. Study III meant measuring stress markers during priority-1 alarms. Study IV was carried out as a longitudinal register study where data about ICD-codes was collected from Statistics Sweden and the National Board of Health and Welfare.

Results: In study I it was shown that the use of lifting aids reduced the measurable stress in the form of both reduced heart rate and decreased cortisol levels. Study II showed that personnel were stressed of the unknown test though women had the highest salivary cortisol levels before the Trier social stress test while the highest value for men occurred 10 to 20 minutes after the test. Study III showed that there was an increase in heart rate during priority-1 alarms that could not be linked to physical activity. It also indicated/showed that traffic accidents, patients with heart attacks in need of acute PCI or thrombectomy and alarms regarding children generate the highest stress onset seen as prolonged elevation of cortisol levels. This was seen regardless of gender, age, education or experience in all three studies. Study IV showed that Swedish ambulance personnel run the risk of being affected by certain diseases such as cardiac arrhythmias and injuries as arthrosis of the knee, dorsopathies and intervertebral disc disorders to a greater extent compared to other health care workers and other professions in Sweden.

Conclusion: Swedish ambulance personnel have a higher incidence of certain health problems and diseases such as paroxysmal tachycardia, atrial fibrillation and flutter, other cardiac arrhythmias, high blood pressure, of the knee and dorsopathies and intervertebral disc disorders compared to other professions. These conditions can be caused by work-related stress, although they are not the only cause. Some factors that cause a stress reaction that can be linked to the ambulance profession have emerged in the studies. But the extent to which these factors alone cause the health problems that Swedish ambulance personnel suffer from is more difficult to determine with certainty based on these studies. Using shoulder straps reduces both heart rate and cortisol secretion.

Clinical implications: Greater use of aids both in terms of lifting, moving and carrying heavy loads should mean that the physical load on the body would be reduced. These aids could also prevent some musculoskeletal problems that have emerged in this thesis by relieving and distributing the burden throughout the body. An important aspect in preventing work-related stress is that sufficient time is given for recovery. The organizations need to be dimensioned so that there is sufficient standby time so that there is time for recovery and reflection but also time for education and training. This is something that is far from reality in many Swedish ambulance organizations. It is also time to seriously discuss what is an actual reality in many countries, namely that employees in the ambulance service can benefit from a lower retirement age after a certain number of years of service.