The objectives of this study were to evaluate the current fitness of an area ambulance service based in Belfast and to quantify the physiological demands of accident and emergency work. From a total staff of 230, 105 (46%) volunteered to undergo a series of fitness tests subject to health state. Results based on body mass indices showed that 52% of subjects could be classified as overweight and 10% of subjects as obese. Fitness levels were similar to other comparable samples and showed the expected but not inevitable decrease with age. A simple work related task (walking at 6 km/h) performed in the laboratory showed that 54% of men over 40 years of age and 24% under 40 found it taxing. This would favour selection for accident and emergency work on the basis of functional capacity rather than chronological age. Accident and emergency work consisted of long periods of inactivity interspersed with shorter periods of relatively intense activity, often above the anaerobic threshold. Lactate concentrations measured during a staged emergency incident also suggested that personnel may work at intensities exceeding their anaerobic threshold. The incorporation of physical fitness standards in the ambulance service may be appropriate and consideration should be given to a reduced age of retirement.