Yet all of them may be helped to some extent by exercise. Still, the advantages of exercise don’t stop there. Here are a few more ways in which exercise can sharpen your brain power.
It spurs brain growth.
As we get older, the birth of new brain cells slows, and our brain tissue actually shrinks. Exercise may be able to reverse that trend. One brain-scanning study of 59 healthy but sedentary people aged 60 to 79 showed significant increases in brain volume after six months of aerobic fitness training, whereas no such changes occurred among controls who did only stretching and toning exercises. The researchers concluded that the improved cardiovascular fitness that comes with aerobic exercise is associated with fewer age-related changes in the brains of older people.
It increases your sensitivity to insulin.
When you eat, your body turns most of the food into glucose, or blood sugar, the main source of fuel for your body, including your brain. In order for that glucose to enter cells, it must be accompanied by the hormone insulin. Unfortunately, in some people, cells become resistant to insulin. The body has to pump out more and more of it, and still blood sugar levels rise, often resulting in Type 2 diabetes. Even if you don’t develop diabetes, insulin resistance is bad for your brain. When brain cells are flooded by glucose, it can adversely affect memory and thinking.
Regular exercise can actually reverse insulin resistance. In fact, your insulin sensitivity increases – stabilising your blood sugar after you eat – for at least 16 hours after a single exercise session. The better your blood-sugar control, the more protected you are against age-related cognitive decline.
It boosts brain-building hormones.
Much like plant food makes plants grow faster and lusher, the chemical known as brain-derived neurotrophic factor, or BDNF, stimulates the growth and proliferation of brain cells. This is especially true in the hippocampus, a region of the brain that is largely responsible for memory and which is particularly vulnerable to age-related cognitive decline. The more you exercise, the more BDNF you produce.
It fights depression and anxiety.
Depression slows the brain’s ability to process information, makes it more difficult for us to concentrate and reach decisions, and causes real memory problems. For serious depression, your doctor may prescribe antidepressants. For milder cases, however, exercise has been shown to work wonders. It cranks up the body’s production of serotonin and dopamine, two neurotransmitters crucial to upbeat, motivated moods. And it boosts levels of the feel-good chemicals called endorphins.
It reduces the effects of stress.
If some hormones make the brain younger, others age the brain. These include the so-called stress hormone cortisol. Slow, scattered thinking and forgetfulness are caused by stress more often than we may realise. Exercise lowers cortisol levels, helping you to think straight again. It is also believed to generate new nerve cells in the part of the brain called the dentate gyrus, an area of the hippocampus linked to the creation of new memories. Brain cells here are seriously depleted during times of stress.
It improves your brain’s ‘executive function.’
Executive function isn’t reserved just for company directors; everyone uses it every day. Essentially, it’s the cognitive abilities that enable us to act like grown-ups, including the ability to focus on complex tasks, to organise, to choose behaviour that’s appropriate to a given situation, to think abstractly, to meet deadlines and to plan for future events. It also encompasses working memory, such as the ability to keep a phone number in your head while you dial.
When researchers set out to analyse the effects of exercise on executive function, they looked at 18 well-designed studies and found that, in men and women aged 55 to 80, those who did regular exercise (particularly a combination of cardio and strength training) performed four times better on cognitive tests than the studies’ control groups, who didn’t exercise regularly. They improved their individual scores by a solid 50 per cent regardless of the type of cognitive task. The effects were greatest among those who had exercised for 30 to 45 minutes each session for longer than six months, but substantial benefits were apparent after only four weeks of exercise.