Exercise is usually sold on what it does for your heart, weight and muscles. The effects on the brain get less attention, though the research behind them is substantial. Here is what the studies show about exercise, memory, mood and dementia risk, and what they don’t show.
- Memory: a year of aerobic exercise grew part of the hippocampus by about 2% in older adults.
- Thinking skills: several kinds of exercise improved cognitive function in people over 50.
- Mood: walking, jogging, yoga and strength training all reduced symptoms of depression.
- Dementia: physical inactivity is one of 14 modifiable risk factors.
- Focus: a single workout gives only a small, short-lived boost.
Exercise and memory
The hippocampus is a part of the brain central to memory, and it slowly shrinks with age. In a trial of 120 older adults, one year of aerobic exercise increased the volume of the front part of the hippocampus by about 2%, effectively reversing one to two years of age-related loss. In the comparison group, who did stretching and toning, hippocampal volume declined [1].
That trial is one of many. A meta-analysis of 39 studies in adults over 50 found that exercise improved cognitive function. Aerobic exercise, resistance training, mixed programmes and tai chi all helped. The best results came from sessions of 45 to 60 minutes at moderate intensity or above [2].
Exercise and mood
A 2024 review in the BMJ pooled 218 trials with 14,170 people with depression. Walking or jogging, yoga, strength training, mixed aerobic exercise and tai chi all reduced symptoms. The effects grew with the intensity of the exercise prescribed, and strength training and yoga were the forms people were most likely to stick with [3].
There is a caveat. Only one of those trials met the standard for low risk of bias, and the reviewers’ confidence in the results was low for walking or jogging and very low for the other types [3]. Exercise is a sensible part of looking after your mood. If you are being treated for depression, it belongs alongside that care, so talk to your doctor before changing anything.
Exercise and dementia risk
The 2024 Lancet Commission on dementia identified 14 risk factors that people can change, and physical inactivity is one of them. The others include high blood pressure, hearing loss, smoking, diabetes and social isolation. The Commission estimated that tackling all 14 could prevent or delay nearly half of dementia cases [4].
Exercise doesn’t guarantee you won’t get dementia. It is one of several things you can control that shift the odds.
What happens in the brain
One explanation researchers point to is brain-derived neurotrophic factor (BDNF), a protein that supports the growth and survival of nerve cells. A meta-analysis of 29 studies found that a single session of exercise raised BDNF levels moderately, and regular exercise strengthened that effect [5]. Those studies measured BDNF in the blood, though, which is an indirect window on what happens in the brain.
Does a workout sharpen your focus?
A little, for a short time. A meta-analysis of 79 studies found that a single bout of exercise had a positive but small effect on cognitive performance, during, straight after and some time after exercising [6]. A walk before a big meeting won’t hurt, but the bigger brain benefits come from exercising regularly over months and years.
How much exercise to aim for
The World Health Organization recommends that adults do 150 to 300 minutes of moderate activity, or 75 to 150 minutes of vigorous activity, each week. It also recommends muscle-strengthening work for all the major muscle groups on two or more days a week. Older adults should add balance and strength activities on three or more days a week [7].
If pain in your back, knee or shoulder is what stops you exercising, that is where physiotherapy helps: sorting out the pain and building enough strength to train consistently.
How we can help
At Aspire Physio Bangkok, our physiotherapists treat the injuries and aches that stop people exercising, then move them onto the gym floor in the same building. See back pain, knee pain and neck and shoulder pain. For more on how the nervous system adapts to training, read why you get stronger before your muscles grow.
Book a free first consultation through our contact page or call 082-281-8009.
Common questions
Can exercise improve your memory?
There is good evidence that it helps in older adults. In a one-year trial of 120 older adults, aerobic exercise increased the size of the front part of the hippocampus, a brain area central to memory, by about 2%, while it shrank in a stretching group. A review of 39 studies found that exercise improved cognitive function in people over 50.
What type of exercise is best for the brain?
Several types work. In people over 50, aerobic exercise, resistance training, mixed programmes and tai chi all improved cognitive function, with the best results from sessions of 45 to 60 minutes at moderate intensity or above.
Can exercise help depression?
Yes. A large review of 218 trials in people with depression found that walking or jogging, yoga, strength training and other exercise all reduced symptoms, with harder exercise working better. Confidence in the evidence is low, so if you are being treated for depression, talk to your doctor before changing anything.
How much exercise do I need for brain health?
The WHO recommends 150 to 300 minutes of moderate activity or 75 to 150 minutes of vigorous activity a week, plus muscle strengthening on at least two days. Older adults should add balance and strength work on three or more days a week.
References
- Erickson KI, Voss MW, Prakash RS, et al. Exercise training increases size of hippocampus and improves memory. Proc Natl Acad Sci USA. 2011;108(7):3017-3022. doi.org/10.1073/pnas.1015950108
- Northey JM, Cherbuin N, Pumpa KL, Smee DJ, Rattray B. Exercise interventions for cognitive function in adults older than 50: a systematic review with meta-analysis. Br J Sports Med. 2018;52(3):154-160. doi.org/10.1136/bjsports-2016-096587
- Noetel M, Sanders T, Gallardo-Gómez D, et al. Effect of exercise for depression: systematic review and network meta-analysis of randomised controlled trials. BMJ. 2024;384:e075847. doi.org/10.1136/bmj-2023-075847
- Livingston G, Huntley J, Liu KY, et al. Dementia prevention, intervention, and care: 2024 report of the Lancet standing Commission. Lancet. 2024;404(10452):572-628. doi.org/10.1016/S0140-6736(24)01296-0
- Szuhany KL, Bugatti M, Otto MW. A meta-analytic review of the effects of exercise on brain-derived neurotrophic factor. J Psychiatr Res. 2015;60:56-64. doi.org/10.1016/j.jpsychires.2014.10.003
- Chang YK, Labban JD, Gapin JI, Etnier JL. The effects of acute exercise on cognitive performance: a meta-analysis. Brain Res. 2012;1453:87-101. doi.org/10.1016/j.brainres.2012.02.068
- Bull FC, Al-Ansari SS, Biddle S, et al. World Health Organization 2020 guidelines on physical activity and sedentary behaviour. Br J Sports Med. 2020;54(24):1451-1462. doi.org/10.1136/bjsports-2020-102955
