If your mouth, tongue, or gums itch when you eat certain foods, chances are, you're having an allergic reaction. If the itching is mild and only in your mouth, it could be oral allergy syndrome, which causes people to react to plant-based foods that contain proteins similar to ones they are allergic to. Or, the reaction could be a food allergy to something like shellfish, wheat, or eggs. Mild, mouth-only symptoms should go away in a few minutes. But, see a doctor if you suspect it's a classic food allergy. If you're also having trouble breathing, go to the ER immediately. It could be a sign of anaphylactic shock, which could be fatal.
Sometimes your heart may race when you wake up suddenly. When you're startled, adrenaline kicks in, and your body's fight-or-flight response is suddenly turned on. If you wake up abruptly from REM sleep, when vivid dreams occur, your heart rate may be naturally elevated. Your heart rate should return to normal within a few minutes. If you also have chest pain or dizziness then it is time to see a doctor.
If your eyelid starts to spasm then you might be stressed, fatigued, or over-caffeinated. It could be what is causing the muscle in your upper or lower eyelid to contract rhythmically. Close your eyes and take a few deep, relaxing breaths to get the spasms to stop. See a doctor if spasms occur regularly or are accompanied by pain.
Does your body jerk as you fall asleep? These hypnic jerks, or sleep starts, probably stem from nerves misfiring as your brain and body downshift into sleep mode. As you fall asleep, your brain signals the body to relax. If the signal is interrupted, it can cause the limbs and head to jerk. There's nothing you can do to prevent these harmless jerks. Fortunately, they last only a few seconds. If they happen frequently or disturb your sleep, they might be a sign of sleep apnea or periodic limb movement disorder so see your doctor.
When you move your feet in a repetitive way during a workout, or if your shoes or laces are too tight, the tiny nerves between the toes can get pinched as you put pressure on your foot causing it to go numb. During your workout, wiggle your toes in your shoes a few times and loosen your laces if they're too tight. If numbness happens during other activities or you can't make it go away. You could have a nerve problem in your foot.
Kristin Appenbrink & Erika Wortham