What causes random adrenaline rushes throughout whole body? Even when doing nothing? Does it mean I'm anxious? 29/f

Stress. Anxiety releases the stress hormones cortisol and adrenaline, this can be produced by your thoughts alone. Negative or fearful thinking can release these hormones. Try using the free anti anxiety app for daily support, exercises, videos and homework to help you lessen anxiety in lasting ways. Best.
Adrenaline. The brain releases adrenaline to prepare you to fight or flee when it detects danger. It may detect danger on a subconscious level even if you are not aware. You may wish to check out my free videos as they may give you a clue: www.Thecoachmd.Com. Rarely are there conditions that will cause this spontaneously. But if you are concerned have it checked out.
Could be. The symptoms you describe could very well be anxiety, even you if don't feel anxious. People with panic attacks and panic disorder have similar symptoms. Since other conditions may cause those symptoms, you should get checked by your family physician or internist, and if they recommend a consultation with a psychiatrist, i would follow their advice. Treatment is very effective and safe.