Research shows the stressful demands of caregiving to older family members can have negative effects on physical health. The effects on physical health may include: immune system functioning, heart rate reactivity, raised blood pressure levels, and increased risk of mortality among older spousal caregivers. Gender differences in caregivers' outcomes exist because, compared with male caregivers, female caregivers face higher levels of caregiving stressors, have fewer social resources, and report lower levels of psychological and physical health.