Exercise does increase GABA as exercise increases your levels of two of the common neurotransmitters which are glutamate and gamma-aminobutyric acid, or GABA which are responsible for chemical messaging within the brain.
Taking GABA Supplements can increase your serotonin and also lower your blood pressure.
GABA supplements are most commonly used to treat high blood pressure and benefit emotional, cognitive, and physical health.
Fruits and Vegetables are a natural way of increasing your Serotonin Levels.
Also taking some Serotonin Supplements as directed can help to increase your Serotonin levels but don't take too many of them at a time as you could get too high of serotonin levels.
To increase your serotonin levels naturally try changing your diet so that you increase your bodies serotonin levels by eating healthy foods that give you energy such as fruits, vegetables and any other foods that contain Vitamin C and other nutrients.
Other things you can do besides changing your diet is to get plenty of sleep, get plenty of sunlight and get plenty of exercise in the sun as well.
In the winter try using a depression light to help boost your energy and Serotonin levels.
You should also try avoiding and lowering your stress levels as well as take a Vitamin Supplement such as Vitamin D or Vitamin C supplements to help boost your mood.
You can also take some fish oil supplements that help to improve your brain health as well and eat fish when possible.
Fish is known as the brain food so you'll have an improved memory when eating fish and your serotonin levels should naturally increase.