As you said this acidity is due to anxiety disorder then you should take proper sleep. Exercise and walk 6k-8k minimum steps daily. Eat healthy and balanced diet. Dont overeat in stress.

Yoga, plenty of vegetables juice, water, even alovera juice Change food type and eating habits *Consult ayurveda doctors or nutritionist

Light food. Plenty fuids. Fingers fruits. Amla in your diet. Cycling Running. And abdominal exercise

First Make Your Schedule for The Activities Of Your Day .. Take Out Some Time Normal Walking Specially After Your Evening Meals. Don't Just Sit or Lie Down After The Meals. Sleeping Only After Two Hour of Meals. Don't Lie on Your Stomach While Sleeping. Drink Adequate Amount of Water. Do Some Pelvic Movements in Standing Position.  Like Front Back, Sideways, Circular Movements. Try Some Breathing Exercises Also. Anolom Vilom.

There are so many reasons for high acidity problem. It could be due to low water intake, irregular timing for food intake, spicy foods, junk food, lack of sleep, late night eating, late night work, anxiety etc.

Their is no exercise for this. Try yoga.

There are many possibilities of acidity dietician will be the one who can help you to reduce this problem. and if you want exercises you can do all exercises for neck shoulder,back legs,brisk walking, cycling , .but to avoid acidity problem take some precautions likes dont sleep late at night.try to do yoga meditation, and take proper sleep. Take a break inbetween your work.try to avoid oilly food.,preserved food, .

Out of what i know, acidity is a physiological problem which would be very vaguely related to lack of exercise. Anxiety is very multifaceted and could be linked to Psychological, physical, social, cultural factors. Exercises do release endorphins which could mediate lesser cortisol levels to some extend.  At the same time any stress reduction plan would often have exercise as a part of it.