What is GABA? Your brain's natural brake pedal

Most of us drive all day with a foot on the gas. Here's the brake pedal you already have, and how to start pressing it again.

Your body has a brake pedal because your nervous system was built to run on two opposing signals: one that speeds you up and one that slows you down. The brake is a chemical messenger called GABA. So what is GABA doing for most of us? Not much, because we drive all day with a foot on the gas and never reach for the brake. Not because we can't. Because nobody ever showed us where the pedal is. In a recent class, I spent the whole hour on that pedal: what it is, what wears it down, and how to press it again. This is for anyone who gets into bed tired and still can't seem to switch off.

What is GABA? The brake in a two-pedal system

GABA stands for gamma-aminobutyric acid. It's a neurotransmitter, which basically means a chemical your nerve cells use to talk to each other.

Your nervous system, like almost everything in your body, runs on a seesaw. A muscle contracts, and then it relaxes. On one side of the nervous system is glutamate, the main excitatory messenger. That's the gas. On the other side is GABA, the main inhibitory messenger. That's the brake. The two are always in a dynamic balance, and when there's enough GABA on board, your brain can shift smoothly between action and rest.

GABA slows the firing of nerve cells. It quiets the alarm. And here's the part I want you to hold onto: GABA doesn't repair itself. It creates the conditions that let your body move into rest, repair, and sleep. Your body already knows how to recover. It just can't do it at highway speed.

If you drove your car fast all day and never touched the brake, bad things would happen. Nobody would treat a car that way. We treat our nervous systems that way every day.

GABA tone: the hum of an idling engine

When I talk about GABA tone, I mean where your system settles when nothing in particular is happening. There are two ways I like to picture it.

The first is a muscle. Clench it as hard as you can and hold it, and you get spasms and a host of problems. Let it go completely slack, and the joint has nothing to react with. Healthy tone is in the middle. You can hold good posture without being tense.

The second is the hum of an engine. Press the gas and the engine revs. Let it drop too low,w and it stalls. Somewhere in between is a steady, healthy idle. That idle is your tone.

One window into this is heart rate variability, which is essentially how flexibly your heart rate adjusts from beat to beat. Many wearables track it, and in essence it's telling you where your engine is idling. For almost everyone I see, it's idling a little too high. The nervous system runs hot and can't find its way back to baseline. That isn't a personality type. It's a state, and a state can change.

What wears the brake pads thin

When the brake can't engage, you feel it. Thoughts race when you want to settle. It's hard to wind down at night, because GABA is part of what gets your body ready to fall asleep. Small things set you off, your shoulders stay tight, and it takes longer to bounce back. It's what I call the false emergency state: your body reacts to ordinary moments as if something were chasing you, not because a threat is present, but because the brake can't catch.

Here's what I see wearing it down.

• Chronic stress. Stress hormones that stay up day after day work against the brake. And the pattern feeds itself: the more often you run the alarm, the more practiced your brain gets at running it.
• The evening scroll. It feels relaxing because it's entertaining. But it's built on quick bursts of dopamine, your reward chemistry, and reward isn't rest. Nerve cells can turn down their sensitivity when they're overstimulated night after night, which is why I describe it as the brake pad getting a little thinner every night.
• Short sleep. Screen light pushes your sleep later, and lost sleep wears on the brake system in its own right. That's a double hit.
• Alcohol. A glass of wine feels relaxing because alcohol acts on the GABA system. You're borrowing a brake. With regular, heavier use, your own system does less of the work, and the borrowed brake has to stand in for the real one.
• Missing building blocks. Your body actually makes GABA out of glutamate. It builds the brake out of the gas, and vitamin B6 is part of that conversion. Magnesium matters too. Without enough of it, the brake pedal exists, but it can't be pressed properly.

Your gut has a line to the brake

One of my classes would never be complete without the gut. Your gut is lined with its own nervous system, with more neurons than your spinal cord, and it produces a large share of your body's neurotransmitters. That includes GABA.

Some of that GABA comes from the natural bacteria in your gut. When researchers in Ireland tested 91 bacterial strains taken from the human intestine, one Lactobacillus strain and four Bifidobacterium strains turned glutamate into GABA in the lab (Barrett et al., 2012). That GABA acts locally on the nerves around your gut, and signals travel up to the brain along the vagus nerve, which is basically the main highway between the two.

Researchers at the same center tested that highway directly. Mice fed a particular Lactobacillus strain showed changes in GABA receptor activity in the brain, a lower stress hormone response, and calmer behavior under stress. When the vagus nerve was cut, those effects disappeared (Bravo et al., 2011). That was one strain, in mice, and we're still mapping how much of it carries over to people. But it tells you the road is real.

This is why I think of fermented foods like kefir, kimchi, and sauerkraut as part of caring for your whole system, not only your digestion. They bring in live bacteria, and the fiber you eat is what feeds the ones already living there. If that distinction is new to you, I walk through it in prebiotic vs. probiotic.

The vagus nerve also works in the other direction, and that's where your breath comes in. When you slow your breathing down, you're toning the vagus nerve and easing the engine back toward idle. A systematic review of 15 studies in healthy people found that slow breathing, under 10 breaths a minute, raised heart rate variability and went along with more relaxation and comfort (Zaccaro et al., 2018). Ten minutes of simply watching your breath and letting it slow is one of the most direct ways I know to find the brake.

Every kind of driver needs a brake.

I've been teaching a set of health archetypes, a way of recognizing who you are when you take care of yourself. Most people recognize themselves in one or two: the guardian, the reclaimer, the craftsman, the warrior, the nurturer, the explorer. What struck me when putting this class together is that every one of them depends on the brake.

The guardian can't protect anything from a chronic state of alarm. The reclaimer can't restore a body whose nervous system won't let go. The craftsman can't build with a tool that never stops vibrating. The warrior can't recover without the ability to stand down. The nurturer can't pour from an empty vessel. Rest is the refill. And the explorer can't see clearly through a nervous system that's running fast.

We live in a world of polarity: action and rest, contract and relax. Most of us live almost entirely on the action side, and when you only inhabit one side, you become unbalanced.

The good news for the warriors is that movement is part of the brake, not the opposite of it. In one small brain-imaging study, GABA levels in part of the brain rose after a bout of vigorous exercise (Maddock et al., 2016). The gas and the brake are meant to take turns.

You don't need to do all of it. Pick one or two and repeat them, because the habit is the result. Every decision in your day either supports the brake or wears it down, and you get to notice which.

Questions I get about this

Can't I just take GABA?

People ask me this every time. Honestly,Swallowing GABA doesn’t do much. There's debate going both ways, and it's hard to see how GABA taken by mouth, passing through your digestive system, would make it up into the brain. That's why I focus on the conditions that let your own system work: the breath, the evening, the gut, the sleep. If you're considering any supplement, talk it over with your own doctor first.

Why does a glass of wine calm me down?

Because alcohol acts on the same GABA system. It's a borrowed brake. An occasional glass isn't the issue. The trouble comes when the borrowed brake starts doing the job your own system is meant to do.

How do I know if my brake is worn down?

Listen to your body. Racing thoughts at night, trouble winding down, a short fuse, tension you can't shake, slow recovery. If you wear a device, watch your heart rate variability trend over weeks rather than day to day. And if sleep trouble or constant worry won't let up, bring it to your own doctor. This is a way of paying attention, not a substitute for care.

References

1. Barrett E, Ross RP, O'Toole PW, et al. γ-Aminobutyric acid production by culturable bacteria from the human intestine. Journal of Applied Microbiology. 2012. PubMed
2. Bravo JA, Forsythe P, Chew MV, et al. Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve. Proceedings of the National Academy of Sciences of the USA. 2011. PubMed
3. Zaccaro A, Piarulli A, Laurino M, et al. How breath-control can change your life: a systematic review on psycho-physiological correlates of slow breathing. Frontiers in Human Neuroscience. 2018. PubMed
4. Maddock RJ, Casazza GA, Fernandez DH, Maddock MI. Acute modulation of cortical glutamate and GABA content by physical activity. Journal of Neuroscience. 2016. PubMed