This research program, which included four studies, was designed to examine the impact of long work hours and other job stressors on blood pressure (BP), cardiovascular disease (CVD) risk, and musculoskeletal disorders (MSDs). CVD is the number one cause of illness and death in the U.S., and high blood pressure is a common and powerful risk factor for CVD. Work- related MSDs, such as low back pain, tendinitis, and carpal tunnel syndrome, account for a large proportion of the cost of work-related illness in the U.S. The first study involved analyses of medical claims filed by unionized hospital workers in New York City to a joint union-management self-insured fund. In the three other studies, 431 hospital workers and 27 home health care workers from New York City completed questionnaires and 276 had their BP measured while working using ambulatory (portable) blood pressure (ABP) monitors, the gold standard in BP measurement. Nurses and nurses' aides participated in the study at Hospital A, while lower status employees participated at Hospital B. Among employees at Hospitals A and B, there was no association between ABP and usual work hours or work hours in the month before ABP measurement. However, data from the medical insurance claim database revealed that registered nurses (RNs) working more than 40 hours per week (averaged over the previous 3 months) were nearly three times more likely to file a medical claim for hypertension (high blood pressure) than RNs working 31-40 hours per week. At Hospital B, in 2000, female nurses and nurses' aides working 12-hour shifts had much higher ABP at work, home and during sleep than those working 8-hour shifts, adjusting for age, race, and other risk factors for high BP. ABP differences between shifts were 4-19 mm Hg systolic and 3-8 mm Hg diastolic. However, this effect was not seen in 1995. At Hospital A, evening, night and rotating shiftworkers had higher ABP than day workers when controlling for age, race, and gender (6.3 mm Hg systolic, 4.5 mm Hg diastolic), but this effect was smaller when controlling for other risk factors for high BP. At Hospital B, compared to day shift nurses and aides, evening shift workers (4 pm-midnight) had higher ABP at work (0- 4.3 mm Hg systolic, -1.3-2.7 mm Hg diastolic), home (1.1-15.6 mm Hg systolic, 2.0-6.2 mm Hg diastolic), and sleep (4.1-9.5 mm Hg systolic, 1.7-6.3 mm Hg diastolic) in both 1995 and 2000. At Hospital A, among women, those with high demand-low control work ('job strain") or high efforts combined with low rewards at work had higher ABP (4.8-6.6 mm Hg systolic and 3.2-4.3 mm Hg diastolic) than those with job strain or effort-reward imbalance. There was some suggestion, although not consistent, of interactions between work hours and other stressors. At Hospital B, overtime worked in the past month was associated with higher work ABP, but only for employees with job strain. At Hospital A, ABP was higher in employees working overtime but only in the group with only a high school education. Occult hypertension means normal office BP (<140/90), but high workday ambulatory BP. In Hospital A, occult hypertension was seen in 16-23% of men and 19-20% of women with normal office BP. Occult hypertension was more common in shiftworkers but not among those working long hours. There was some suggestion of higher risk of occult hypertension among workers facing job strain or high efforts combined with low rewards. Some research has found that depression, anxiety, short sleep hours and fatigue are risk factors for future heart disease. At Hospital A, employees working more than 40 hours per week had higher levels of fatigue, but not more symptoms of anxiety or insomnia. Employees with paid work plus home tasks totaling more than 57.5 hours per week were more than four times more likely to report symptoms of depression (but not fatigue, insomnia or anxiety). Employees facing job strain or high efforts combined with low rewards at work were also more likely to report more symptoms of depression, anxiety, insomnia and fatigue. Hospital service and maintenance workers and licensed practical nurses/nurses' aides (jobs with substantial ergonomic risk factors) were nearly two times as likely to file a medical claim for a low back musculoskeletal disorder (MSD) than paraprofessional hospital workers such as social workers, physicians' assistants, emergency medical technicians or pharmacists. Male hospital workers working more than 50 hours per week (averaged over the previous 3 months) were 50% more likely to file a medical claim for a low back MSD, and those working 46 or more hours per week were more than four times more likely to file a medical claim for wrist/hand MSDs. However, women working more than 50 hours per week were only half as likely to file a medical claim for a neck MSD. Work hours were not related to shoulder MSDs. In case-control analyses among a subset of participants who completed the study questionnaire, neither work hours in the 1-3 month nor the 4-6 month periods prior to filing a medical claim were significantly associated with claims for MSDs. The results of these studies suggest that programs and policies to reduce employees' exposure to work stressors, including long weekly work hours, 12-hour shifts, evening shifts, high demand-low control work and high efforts combined with low rewards at work, can be implemented in order to reduce the chance that employees will develop high BP, heart disease, stroke, and work-related MSDs. Employer programs and policies need to be carefully evaluated for their health effects. Various programs and policies have been recommended by researchers and government agencies (such as NIOSH) including: worksite surveillance (periodic surveys and medical exams, screening for occult hypertension, and analyses of existing medical claim databases); integration of health promotion (programs for exercise, healthy diet and smoking cessation) with occupational health approaches (reducing sources of stress in the workplace), and job redesign (for example, increasing employee participation and control and increasing work rewards, which include respect support, income, promotion prospects and job security).