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How exercise strengthens your brain and reverses ageing

  • Regular exercise can improve mood and the brain’s ability to function including coping with stress

  • Exercise causes positive changes in the brain, which prepare it to rewire disturbing neural pathways imprinted in childhood

  • Simple exercise guidelines can improve brain health and function.

It’s been known for years that regular exercise improves depression, anxiety, low self-esteem, troubled sleep, fatigue, and other symptoms related to stress. So exercise is particularly beneficial for survivors of adverse childhood experiences, who frequently struggle with symptoms of this nature.

In recent years, we’ve learned how exercise strengthens the brain, preparing it to rewire—to form new neural pathways that will overwrite the distressing neural pathways that are formed in the early years, keeping the brain on high alert.

It’s all about the master molecules

Exercise increases the master molecules in the brain, such as brain-derived neurotrophic factor (BDNF). Without exercise, these molecules tend to decrease with stress and ageing. Collectively, the master molecules:

  • Increase brain volume which is done by neurogenesis (growth of new neurons), growth of new capillaries, growth of new tissue that supports the neurons

  • Improve the health and functioning of neurons (hence the explanation as to why exercise improves cognitive function)

  • Raise levels of antioxidants. Antioxidants limit damage to neurons caused by oxidative stress—therefore keeping neurons alive for longer

Irisin is a recently discovered hormone found in humans and animals. Irisin is produced during exercise by the muscles and possibly the brain. In animal studies, Harvard researchers found that Irisin appears to increase neurogenesis, decrease inflammation, and keep brain cells healthy and functioning.


Chronic, low-grade inflammation affects millions of people and is linked to brain damage, cognitive decline, depression, and many of the leading causes of death (such as heart disease, cancer, and type 2 diabetes). The immune system normally mobilises whenever it detects invading germs, toxins, or tissue damage. For unknown reasons, however, the immune system can remain on high alert and begin to attack the body’s healthy tissues, including the brain.

Signs and symptoms of chronic inflammation include sleep disturbance, fatigue, depression, anxiety, achy muscles and joints, gastrointestinal distress, headaches, and brain fog. Notice the overlap between these symptoms and stress-related mental disorders.

Neuroinflammation (inflammation in the brain or spinal cord) might also suppress neurogenesis. Furthermore, neuroinflammation seems to promote the growth of the toxic proteins associated with Alzheimer’s disease. Exercise appears to reduce brain inflammation and these harmful proteins, which is probably why numerous studies link exercise to less dementia, including Alzheimer’s disease.

Obesity is one risk factor for inflammation, as fat cells produce pro-inflammatory chemicals. What’s an important tool for fighting obesity? Regular exercise!

Regulate your stress

One of the problems with unresolved trauma is that stress arousal can become stuck on too high or too low. In these extreme states, where the overriding urge is to fight or flee, key areas of the brain go offline—such as the areas associated with clear thinking, rational speech, and feeling connected to self, emotions, and your body.

Exercise helps to return arousal to the resilient zone, in which it is neither too high nor too low, and all regions of the brain work together again. This is accomplished either by expending the energy of high arousal or by reversing the immobilisation of low arousal. Regulating arousal levels in these ways not only favours optimal mood and function in the present but also readies the brain for later processing and settling of disturbing memories from childhood. In addition, exercise regulates the stress hormones suspected to promote chronic, low-grade inflammation.

Small changes

Experts consider exercise to be the best-established way to increase neurogenesis and an excellent way to increase overall well-being. Fortunately, small changes can reap large benefits in just weeks or months. In one well-designed study, sedentary adults with mild cognitive impairment began to exercise aerobically three times a week and follow a healthy diet. After six months, the subjects showed a nine-year reversal of brain ageing. Studies also show that people in their nineties can increase muscle strength greatly in just two months.

Exercise guidelines

  1. Start gently and gradually work up to at least 150 minutes a week of moderate-intensity aerobic exercises, such as walking, cycling, or swimming. This could be, for example, about 30 minutes per day five days of the week. You can also break up your total daily exercise time into shorter sessions, say three 10-minute sessions a day.

  2. You can add strength and flexibility training to increase the benefits of exercise. Strength training can involve resistance bands, free weights, strength training machines, or moving your body weight (push-ups, pull-ups, or exercises that develop core muscles that help you move better). Strength training is recommended two to three times a week on non-consecutive days. Build up gradually to two to four sets of10 repetitions per set.

  3. Don’t overlook yoga, which helps to reduce the stress that is linked to neuro-inflammation.

  4. Try outdoor exercise in the morning. Sunlight raises levels of vitamin D, which improves brain function in many ways. About 20 minutes of sunlight is usually safe and sufficient to produce significant amounts of vitamin D. Morning exercise in the sun also strengthens sleep cycles and improves sleep. In addition, morning exercisers are more likely to stick to their exercises regimens.

  5. Complex motor movements, such as dance, racket sports or playing an instrument, lay down useful neural pathways.

Of course, to be safe, consult with your doctor before beginning an exercise program.

High-intensity interval training

High-intensity interval training (HIIT) yields benefits similar to moderate-intensity exercise but in about half the time. This makes HIIT appealing to on-the-go individuals.

HIIT alternates short bursts of high intensity with recovery intervals. The high-intensity intervals typically last 30 seconds to three minutes, followed by longer recovery intervals of moderate intensity. High intensity means the heart rate is elevated to at least 70 percent of one’s maximum heart rate (calculated by subtracting one’s age from 220 and multiplying that number by .7 or slightly higher).

There are different variations. One successful protocol with older adults simply alternated slow walking with fast walking, for three minutes each, for at least 30 minutes, most days of the week.

HIIT can be done in the water, on a treadmill, or on a stationary bike. Start slowly— 15 seconds or less of high-intensity bursts alternating with recovery periods of at least 30 seconds.

Do no more than two or three HIIT sessions per week, allowing two days for recovery between HIIT workouts. On the other days, do low or moderate-intensity activities.


At some point, you may wish to explore ways to settle distressing old neural pathways and replace them with positive, uplifting pathways. For now, exercise can optimize mood and your ability to cope with stress in the present, while preparing your brain to maximise the potential of neuroplasticity.

Exercise is clearly vital for good mental health and a healthy brain. Aim for a satisfying exercise plan that you can stick to for many years to come.


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