The physical environment of the health care facility can have a significant impact on the patient's response to treatment. Healing is enhanced when the patient is relaxed, calm, or is even distracted from the medical procedure. A soothing environment eases tension and anxiety when the autonomic nervous system responds by slowing the heartbeat and breathing rates, and reducing blood pressure. Patients can let their mind wander through the serene view on the wall or ceiling, rather than dwell on the medical procedure at hand. Patients who are calm are less likely to fidget, thus less likely to disrupt the medical procedure. Time passes more quickly for the patient who has a pleasing visual focal point. "Nature is one of the most successful sources of positive distraction. Simply viewing a mural of a water scene has been shown to alter electrical activity in the brain, reduce levels of stress hormones and ease muscle tension." Beth Frankowski Jones, ISdesigNET Magazine Realistic photographic images are better suited for the medical setting than abstract art. Realistic scenes stimulate the patient's imagination in a gentle and comforting way, allowing the patient's mind to calmly wander through the familiar view. Abstract art tends to generate unpredictable responses in patients. Some patients will react negatively to harsh colors, sharp angles, or swirling designs. Where one patient might visualize a pleasant pattern, another patient might see an angry image. Patients can even become subtly agitated by abstract designs - just enough to increase anxiety when it is least desirable. "Abstract pictures and nature scenes depicting high levels of activity actually tend to raise anxiety levels in patients, higher even than those with no source of distraction at all." Roger Ulrich, Texas A&M University