The best thing you can do for your brain today takes less time than scrolling through social media.

Twenty minutes of high-intensity interval training (HIIT) releases molecules that help grow new brain cells, strengthen neural connections, and turn your brain into a more efficient thinking machine.

How HIIT Rewires Your Brain

Exercise benefits overall health, but its effects on the brain are particularly striking. When we move, our muscles activate metabolic pathways and release signaling molecules called myokines that communicate with major organs, including the brain, supporting cognitive function in multiple ways.

Short bursts of all-out effort exercise are especially effective. They push muscles to adapt in ways that increase brain-derived neurotrophic factor (BDNF), a protein that helps brain cells grow, stay flexible, and use energy efficiently after just a single HIIT session.

HIIT also increases insulin-like growth factor-1 (IGF-1), which helps activate BDNF. IGF-1 can cross the blood-brain barrier, where it supports the formation of new brain cells and reinforces neural connections, helping the brain learn, adapt, and retain information more efficiently.

Beyond growth factors, sprint intervals—a more intense form of HIIT—improve how the body metabolizes glucose and increase lactate, a substance the brain can use as fuel. “Brain benefits of HIIT come largely from the production of lactate,” Paul Ehren, a master personal trainer and functional nutrition practitioner, told The Epoch Times.

For years, lactate was seen as a waste product and blamed for muscle fatigue. We now know it’s a valuable fuel that can cross the blood-brain barrier, powering neurons and sparing glucose for other essential processes, Ehren said.

The effects of HIIT on the brain have been observed in research settings. In one study, young men who completed a 20-minute workout consisting of six 30-second all-out sprints with short breaks in between performed better on memory and problem-solving tests immediately after the workout.

How to Make HIIT Work for You

If short, intense workouts can sharpen the brain, the next question is, how do we approach them in a way that actually works? When it comes to HIIT, consistency matters far more than pushing yourself to the limit once or twice.

“To get benefits from any exercise protocol, the most important aspect is adherence,” Ehren said. “If someone doesn’t stick with the program, it’s useless. Asking many people to go ‘balls out’ every time they exercise can actually be very counterproductive.”

There’s also no single HIIT formula that’s best for brain health. Protocols vary widely, but they all follow the same basic pattern: a period of intense effort followed by rest.

For example, a classic Tabata session typically involves 20 seconds of effort followed by 10 seconds of rest, repeated over four minutes. The Nordic 4 × 4 protocol, on the other hand, consists of four minutes of hard effort followed by four minutes of rest, with the intense phases reaching roughly 85 to 95 percent of maximum heart rate, Ehren said.

For people new to HIIT training, the goal isn’t to jump straight into these formats. Starting with one or two HIIT sessions per week is often enough to see benefits. Shorter bursts of intensity—around 10 to 15 seconds—can be a good place to begin, with longer recovery periods in between. As fitness improves, the intense intervals can gradually be extended. Allowing at least a day of rest between sessions helps the body recover, and choosing an activity you enjoy—such as cycling, rowing, brisk hill walking, or swimming—makes it easier to stick with it over time.

“Some people will definitely resist it, because it’s bloody hard,” Ehren said. That’s why starting small can make a real difference. Gradually building intensity over time allows confidence and fitness to develop, making it far more likely that people will stick with it—and ultimately reap the brain benefits HIIT offers.

That said, HIIT isn’t suitable for everyone. People with heart conditions, joint problems, or other medical concerns should speak to a health care professional before starting. The same applies to anyone who hasn’t exercised in a long time or is unsure how their body will respond to high-intensity training.

Fueling Before, During, and After HIIT Sessions

What you eat before and after your workout can help determine how much benefit your brain gets from it. Proper fueling supports energy levels, focus, and recovery—all of which matter when exercise is meant to sharpen the brain and not leave you depleted.

“Timing and simplicity are key,” Angel Planells, registered dietitian nutritionist, told The Epoch Times.

Pre-HIIT–30 to 180 Minutes Before

The goal before an HIIT session is to provide easily digested energy. Planells recommended focusing on carbohydrates with a small amount of protein, while keeping fat and fiber low so digestion doesn’t compete with performance.

Pre-HIIT fueling examples include:

• A small smoothie made with half a banana, berries, and water


• A banana with a tablespoon of peanut butter


• A slice of toast with honey or jam


• A low-fiber granola bar


• 1/2 cup Greek yogurt with a drizzle of honey

If you’re eating less than 30 minutes before a workout, around 15 to 30 grams of carbohydrates is usually enough. If you have one to two hours, aim for 30 to 60 grams. Hydration also matters—drinking one to two cups of water in the hour before training can help support performance.

During HIIT

Most people don’t need fuel during an HIIT session. For workouts under 45 minutes, water is sufficient.

If the session lasts longer, or if you’re sweating heavily, an electrolyte drink—no- or low-calorie—can help. For longer or back-to-back interval sessions, a sports drink providing 15 to 30 grams of carbohydrates may be useful.

Post HIIT–Within 30 to 60 minutes

After training, the body is primed to replenish glycogen stores—its backup fuel tank, essentially—and repair muscle. Ideally, food should be eaten within 30 to 60 minutes, but if that’s not realistic, liquid nutrition can work just as well. The focus should be on pairing carbohydrates with protein—carbohydrates help refill glycogen, including the glucose the brain relies on for energy, while protein provides the building blocks needed for muscle repair and recovery.

Post HIIT workout replenishing examples include:

• A yogurt parfait with berries and granola


• Tuna with crackers and an apple


• A protein shake with fruit


• Scrambled eggs with toast and fruit


• A simple chicken, rice, and vegetable meal

A good target is 20 to 30 grams of protein and 40 to 60 grams of carbohydrates, along with enough fluid to replace sweat losses. Water is usually sufficient, but electrolyte tablets can help after especially sweaty sessions.

For those doing morning HIIT who don’t tolerate a full meal early, Planells suggested keeping it minimal. “Try something small to boost carbohydrate stores,” he said, such as half a banana, a handful of crackers, or a small glass of juice.

Twenty minutes of high-intensity interval training can sharpen your mind as effectively as it strengthens your body. The key is finding a sustainable approach—one that fits your schedule, matches your fitness level, and makes you want to come back.

Start small, fuel smart, and let the biochemistry do the rest.