Stress clearly opens the door to many illnesses, but no single disease has been proven to be caused solely by stress. The direct effects of the stress system—to raise the pulse, blood pressure, and blood sugar—can bring on or worsen hypertension, diabetes, arrhythmias, and heart conditions in susceptible people. Cortisone antagonizes insulin, which worsens the metabolic syndrome, leading to weight gain, high cholesterol, and heart disease. Many digestive diseases can be triggered by stress, including irritable bowel syndrome, colitis, ulcers, and acid reflux. The suppression of the immune system by stress makes you more susceptible to infections, even the common cold, and interferes with normal healing.

Over time, with the fatiguing of the adrenals, the immune system can become overactive and lead to allergies or autoimmune diseases, such as lupus and rheumatoid arthritis. The impact on the bone worsens osteoporosis and delays growth in children. Chronic fatigue and fibromyalgia are both exacerbated by stress, as are respiratory problems such as asthma. Psychological disorders, including depression, anxiety, obsessive- compulsive disorder, and alcoholism are all greatly influenced by stress. Chronic stress clearly distorts the normal functioning and balance of the body systems.