My old tennis coach used to remind us before returning serves that we had to get our "pups" shuffling. He was so much wiser than I realized at the time. If you want more usable brain cycles available at 10a while work is serving you up one problem to solve after another, start with your feet. Not a pill. Not an app. Just more movement. It’s not going to get the TikTok pseudo-productivity influencers hyped up and garner millions of views, but it actually works. I'll tell you how much here.

I’m not asking you to restructure your life around exercise. I’m asking you to hear me out about how it does as much for your mind as it does for your body: fewer mental flubs, easier task switches, better recall for items on the tip of your tongue. The numbers are small-to-moderate from published trials and obvious relatively quickly  – if you give enough time and effort to reap the rewards of consistency.

If you’re basically sedentary (most US adults) and generally healthy (unfortunately, not most US adults), aerobic training improves memory a lot and executive function enough to notice. In pooled randomized trials, memory jumped by ~0.8 SD and executive function by about a third.¹ This isn’t placebo; it’s repeated, improved cognitive outcomes in people who weren’t doing much steady cardio to begin with.

Across dozens of trials in middle-aged and older adults, aerobic sessions – twenty to sixty minutes, three to seven days a week, low-to-moderate effort for three to six months – improved working memory, cognitive flexibility, and inhibitory control (call it ~0.4, ~0.3, and ~0.2 SD).² It’s definitely an investment, let’s call it 4 hours per week of cardio, times 12 weeks so around 50 total hours sunk in, gives you very tangible results. And this is not taking into account improvements in mood (very well established), improvements in metabolic health (very well established) and improvements in sleep quality (also very well established) that you get from consistent cardio.

If you need something today, do twenty minutes at a conversational pace. It’s popularly called Zone 2 training, and you can Google it if you want to go deep into the weeds about what it is, or read the “Exercise” section in Defragging Your Mind for more information. Target a heart rate at 70% max (and max is typically 220 - your age). One recent, tidy experiment: older adults cycled at moderate intensity (60% HRmax, calculated oddly in this trial, but whatever) for twenty minutes or sat idle. The riders made fewer impulsive errors and fewer spatial working-memory mistakes when tested right after the bout.³ The benefits probably extend for about an hour acutely – that’s a decently usable window. Put your deep work there.

If you compare this with real-life exercise equivalents, daily experience agrees. When you track people with accelerometers and in-the-moment tests, each extra active minute in the prior twenty minutes maps to a small mental speed gain. Stack up those active minutes before a focus block and your results will improve.⁴

There’s another piece to this activity puzzle: it’s not just cardio that helps your mind. Beef up those gains with pushing up plates at the gym and your prefrontal cortex also gets (metaphorically) swole. Resistance training shows moderate gains in overall cognition in older adults – healthy and mildly cognitively impaired – with short-term memory benefits clearest in the healthy.⁵ This is the domain that decides whether you stick to your task through distraction or careen out to respond to your plethora of pings.

A recent trial was conducted over twenty-six weeks of progressive lifting, twice a week, in older adults at risk for type 2 diabetes. It found better task-switching, better sustained attention and better conflict resolution. Brain scans moved with the behavior.⁶ A different twelve week study found resistance training leading to faster Go/No-Go responses and thicker entorhinal cortex – the faster the responses, the thicker the cortex.⁷ Getting all pumped up at the gym isn’t just for aesthetics anymore. Six pack abs are sexy, sure, but so are six-tenths of a standard deviation improvement in cognition (or 0.58 if you want to be a pedant).

If you want the podium results: a recent comparison across exercise types ranked resistance training first for global cognition in healthy older adults.⁸ Cardio still matters, and for me is my exercise of choice, you’ve always got to consider the study populations when extrapolating how a result should impact your individual choices. But basically don’t skip leg day.

You can also combine modalities. Concurrent training – some cardio, some lifting – delivers global cognitive benefits, with the biggest wins in older and clinical populations (but normal adults still significantly benefit). Program your sessions like an adult: thirty to sixty minutes, four to twenty-six weeks, add in the weights.⁹ The more you do the better you’ll feel and think.

If you’re just starting out, don’t be a hero (and consult a physician):
– Cardio: 20–45 minutes, 3–5 days/week, moderate/Zone 2 pace where you can talk if you have to but it’s uncomfortable. Give it 12 weeks before you cast any judgment.²
– Resistance: 2–3 sessions/week. Squat, hinge, push, pull, carry. Not by yourself. Not without guidance from an actual professional, not your cousin who likes to lift. Progress the load safely. Expect moderate gains in global cognition by 12 weeks and visible improvements in switching and impulse control. ⁵ ⁶
– Need a mental edge today? Do 20 minutes before showtime. Use the 60 minutes that follow as your golden hour of productivity.³ ⁴

If you already lift, bro:
– Keep a short aerobic primer before focus work. Those last-20-minutes effects add up.⁴
– Don’t drop the plates, bruh. If your day is context switching and temptations to literally Slack off, strength training’s edge in inhibitory control is the lever that could move the Earth.⁸ ⁹

You might ask: “How big is big?” As I’ve said, most effects land in the small-to-moderate range. That’s okay. Magic beans don’t exist. This will definitely help in small, repeatable, predictable ways. On resistance days you aren’t just “tired in a good way.” You are changing how control circuitry in your brain behaves under cognitive load – which is why the benefits show up on tasks that are real life.⁶ ⁷

I can already hear your very quotidian, obvious objections:

“I don’t have time.” Stop it. You have twenty minutes. Put it before the thing that pays your bills and it will suddenly (or in 12 weeks) be easier to pay your bills. If you can’t find twenty minutes, the problem isn’t your under-developed physiology. It’s your calendar or prioritizing abilities. There are always tradeoffs. Maybe you cut out playing Candy Crush and instead crush some pullups. 

“Cardio makes me sleepy.” Then you went too hard and were probably in Zone 3 or 4, which is your fault. Go easier. It’s weird to say, because it goes against a lot of conventional beliefs about exercise, but harder is not always better and harder for this consistent, cognitive cardio (TRADEMARK?) it is slow-and-steady winning the race. Stay close-to-conversational. Save sprints or threshold training for a different workout.

“Can I just walk more?” For focus windows, yes, especially if you push to get into Zone 2. Not a lazy stroll, an actual HR-monitored walk with purpose. But for replacing progressive loading in resistance training, no. They do different jobs.⁴⁵

None of this is glamorous. Well, it can be if you get those abs shredded enough to get out laundry stains. But that’s not really the point. The point is: working your body helps your mind work. Don’t focus on tricks for focus. Have a routine of physical activity and your brain will reward you with more, high quality output.

 

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References

1. Hoffmann CM, Petrov ME, Lee RE. Aerobic physical activity to improve memory and executive function in sedentary adults without cognitive impairment: A systematic review and meta-analysis. Preventive Medicine Reports. 2021;23:101496.
   

2. Ye M, Song T, Xia H, Hou Y, Chen A. Effects of aerobic exercise on executive function of healthy middle-aged and older adults: A systematic review and meta-analysis. International Journal of Nursing Studies. 2024;160:104912.
   

3. Martini M, Enoch J, Kramer AF, et al. The effects of a short exercise bout on executive functions in healthy older adults. Scientific Reports. 2024;14:28827.
   

4. Kekäläinen T, Stenfors N, Egli M, et al. Physical activity and cognitive function: moment-to-moment associations in daily life. International Journal of Behavioral Nutrition and Physical Activity. 2023;20:68.
   

5. Coelho-Júnior HJ, Marzetti E, Calvani R, Picca A, Arai H, Uchida M. Resistance training improves cognitive function in older adults with different cognitive status: A systematic review and meta-analysis. Aging & Mental Health. 2022;26(2):213–224.
   

6. Furlano JA, Clarke J, Keage H, et al. Changes in cognition and brain function after 26 weeks of progressive resistance training in older adults at risk for type 2 diabetes: A randomized controlled trial. Canadian Journal of Diabetes. 2023;47(2):239–248.
   

7. Kušleikienė S, Šeikinaitė J, Vints WAJ, et al. Cognitive gains and cortical thickness changes after 12 weeks of resistance training in older adults with low and high risk of mild cognitive impairment: Findings from a randomized controlled trial. Brain Research Bulletin. 2025;222:111249.
   

8. Zhang J, Zhao Y, Liu Y, et al. Optimal exercise interventions for enhancing cognitive health in older adults: A network meta-analysis. Frontiers in Aging Neuroscience. 2025;17:1510773.
   

9. Zhang M, Fang W, Xu Q, et al. Effects of human concurrent aerobic and resistance training on cognitive health: A systematic review with meta-analysis. International Journal of Clinical and Health Psychology. 2025;25(1):100559.