Because speed causes hyperactivity and forces muscles to tighten, your body temperature may rise sharply. This can be worsened by the high temperatures that often prevail in venues like dance clubs.
Body temperatures of up to 42 degrees Celsius have been measured. Such overheating is one of the most harmful effects of amphetamine on your body. High temperatures like these can lead to brain injuries.
Another consequence of overheating is an excessive loss of body fluids from sweating. This causes dehydration. Overheating combined with dehydration has been a cause of death for some speed users.