The workouts that boost the fitness of your brain

The latest research reveals we should all be exercising not just to maintain physical fitness but for our cognitive health. So what are the rules?

The latest research reveals we should all be exercising not just to maintain physical fitness but for our cognitive health. Picture: istock

A brisk walk is good for your body but it will also bolster your brain. In the latest study to confirm that exercise enhances mental as well as physical fitness, researchers at the University of Texas Southwestern (UTSW) medical centre found that when older adults with mild memory loss started walking frequently they not only improved their cognitive scores but also experienced a significant increase in healthy blood flow to their brains.

In the trial, published in the Journal of Alzheimer’s disease, 48 participants with the kind of mild cognitive impairment that affects memory and is a risk factor for developing Alzheimer’s were assigned to either a stretching group or an aerobic exercise group, mostly brisk walking on treadmills. Each group did 30 to 40 minutes of their activity, three to five times a week. At the end of the year-long study the brisk walkers showed decreased stiffness in the blood vessels of their neck and increased overall blood flow to the brain – and the fitter they became (as measured by their total oxygen consumption, a laboratory measure of aerobic fitness) the greater these improvements were. “We’ve shown for the first time in a randomised trial . . . that exercise gets more blood flowing to your brain,” said Rong Zhang, a professor of neurology at UTSW and the study leader.

It adds to the evidence that exercise benefits the brain. “We now know that not only does the brain rejuvenate itself by growing new cells but that exercise appears to be among the best ways to promote this neurogenesis,” says James Goodwin, a visiting professor at Loughborough University and the author of a new book, Supercharge Your Brain. “Exercise generates proteins called irisin and cathepsin B in the muscles and, through blood flow to the brain, these proteins reach the neurons and stimulate production of a chemical called BDNF [brain-derived neurotrophic factor] that maintains existing brain cells, stimulates the growth of new ones and helps to create connections between them.”

Goodwin says that we should all be exercising not just to maintain physical fitness but because it is the best thing we can do for our cognitive health. So what are the rules for boosting mental fitness?

WORK OUT HARD FOR 40 MINUTES

It’s not just what form of exercise you do but how you do it that matters, Goodwin says. “If you want to max out on BDNF production it will take 40 minutes of continuous exercise performed at 80 per cent of your highest effort.” Scientists use MET (metabolic equivalent of task) values as a guide to the intensity of exercise and he says that any activity of MET 5, meaning you’re exerting five times the energy you would if sitting still, or higher is beneficial. Cycling at a moderate pace has a MET value of 6 to 8.5, skipping is 12.3, jogging is 6 to 7 and faster running at about 6 minutes per mile can be as high as 16.

Emerging evidence suggests that there may be subtle sex differences in the brain fitness responses to varying intensities of exercise. In one paper published in the journal Nature Human Behaviour last year, sports scientists at the University of Basel found that in females of all ages the positive brain effect of vigorous exercise “disappears if the intensity is increased too quickly”, meaning that women should perform low to medium intensity activities for longer duration to increase their cognitive fitness. In men, working up to and then maintaining a high intensity level brought the most significant improvements. In general, though, scientists say that the more effort you put into a workout the better. “Exercise until you are red-faced for 40 minutes a day is the message for your brain,” Goodwin says.

YOGA IS A BRAIN BOOSTER

Mats Hallgren, an assistant professor in the department of global public health at the Karolinska Institute in Sweden and the lead author of a review published in the journal Complementary Therapies in Medicine next month, says that, practised regularly for about 45 to 60 minutes at least three times a week, yoga brings brain health benefits on a par with cardiovascular activity. “So far research suggests that the magnitude of the benefits of yoga and aerobic exercise on cognition are approximately equal.”

Yoga increases blood flow to the brain so that there is more glucose circulating. Picture: istock

Like other forms of exercise, yoga increases blood flow to the brain so that there is more glucose – the “fuel” that enables it to function efficiently – circulating, but it offers additional benefits, including better balance, co-ordination and flexibility.

“Regular practice of yoga may also change the brain’s structure and ‘plasticity’ by increasing the number of neurons in key areas of the brain associated with learning, memory and executive functioning, including prefrontal context, hippocampus and amygdala,” he says. “Over time yoga may help the brain to generate new cells within these regions and also improve the communication between the different brain areas.

“The net result is that the brain works more effectively, and this can be assessed using cognitive tests.”

EXERCISE BEFORE BREAKFAST

As a founding member of the Global Council on Brain Health, Goodwin says that he has sifted through hundreds of published papers on activity and cognitive maintenance in recent years. The 71-year-old has since “completely changed his lifestyle”. He eats his last meal before 8pm each day and gets up at 8am the next morning to drink a large mug of black coffee and head out for a three-mile run.

“I don’t eat anything until 10am, after I get back and have showered. It means I force my brain to flick the metabolic switch from relying on glucose to relying on ketones, and all of the evidence shows that if we exercise on empty like this on a repeated basis it is immensely helpful for preventing brain ageing.”

TRY T’AI CHI AND TEAM SPORTS

Regular exercise will help your brain to produce new cells but Goodwin says that you then need to engage in activities that cement them in place and enable them to make new connections. “If these new cells are just left to their own devices then they will go into preprogrammed cell death and most will die within two to three weeks. It requires cognitive-stimulating activities to maintain them, and that means anything that involves the sustained effort of learning a physical skill.”

Mind games are not enough. “Dancing and t’ai chi are excellent examples of activities that will cement your brain cells,” Goodwin says.

Sports and activities that challenge co-ordination and require more complex movement patterns along with interaction between participants were shown in the University of Basel research to provide an added edge for the brain. “To co-ordinate during a sport seems to be even more important than the total volume of sporting activity,” says Dr Sebastian Ludyga, an exercise scientist and a lead author of the paper.

RUN YOURSELF SMARTER

Any form of aerobic exercise – including stair-climbing, cycling and running – has the power to improve thinking power in young as well as older adults, according to a study published in the journal Neurology.

Participants were randomly assigned to aerobic exercise or stretching four times a week. After six months the aerobic exercise boosted a specific set of thinking skills called executive function, which is related to attention, focus and achieving goals, significantly more than the stretching routine. “We found that all participants who exercised aerobically not only showed improvements in executive function but also increased the thickness in an area of the outer layer of their brain,” said the study’s author, Yaakov Stern, a researcher at Columbia University in New York and a member of the American Academy of Neurology.

Any form of aerobic exercise has the power to improve thinking power in young as well as older adults. Picture: istock

Running may hold particular benefits. A 2020 study by the University of California San Diego suggests that running on a treadmill may increase brain plasticity – the brain’s ability to change and adapt – and enhance motor skill acquisition.

Add short, hard bursts of high-intensity interval training (HIIT)-style sprints and the return could be greater. German researchers showed how runners who incorporated two three-minute bouts of high-intensity sprints into a 40-minute run produced much higher levels of BDNF and performed 20 per cent better in post-run cognitive skill tests than those who ran at a more leisurely pace.

BODY BUILD YOUR MEMORY

A team of Australian researchers working with men and women aged 55 to 86, all of whom had mild cognitive impairment, asked half of them to do stretching exercises twice a week and the others to do weight training (lifting 80 per cent of the maximum amount they could) twice a week for six months. The weight training group scored significantly higher in cognitive tests at the end of the study than at the beginning and retained their improved level after 12 month. The stretching group’s scores dropped.

A University of Sydney study found weight training is beneficial for cognitive health. Picture: istock

Even for people at high risk of dementia and Alzheimer’s disease, lifting weights is beneficial.

“Strength training can protect some hippocampal subregions from degeneration or shrinkage for up to 12 months after the training has stopped,” said Dr Kathryn Broadhouse, who led the research at the University of Sydney.

The Times