Hypothyroidism is characterized by:

1. Weight gain, caused by decreased metabolism.

2. Slow response to stress (“fight or flight” response), caused by decreased sensitivity to adrenal hormones.

3. Slower reflexes and decreased muscle tone.

4. Fatigue, caused by decreased cardiac output and slower heart rate.

5. Constipation, caused by decreased gastrointestinal motility.

Hyperthyroidism is characterized by:

6. Weight loss, caused by increased metabolic rate.

7. Heightened stress response, caused by increased sensitivity to adrenal hormones.

8. Tremors and twitching, caused by increased muscle tone and reflexes.

9. Fatigue, caused by irregular heart beat (palpitations) due to increased cardiac output and faster heart rate.

10. Diarrhea, caused by increased gastrointestinal motility.