Why exercise is about more than just weight

We know that physical activity is crucial to age-proofing your brain because it lowers your BMI and weight — two risk factors for cognitive decline. But the latest science shows that exercise actually boosts brain power directly. Dr Briffa explains: “It stimulates blood supply to the brain and stimulates something called BDNF (BrainDerived Neurotrophic Factor), which is good for the brain, protects it from damage and even stimulates the production of brand new brain cells.”

BDNF is manna for the brain. Higher levels increase the volume of the hippocampus, the part of the brain involved in making and storing memories. One study showed that women with higher levels of BDNF not only scored better on their BMI, but had higher scores on memory tests. Low levels are linked to accelerated ageing, depression, even schizophrenia.

Intense exercise is the key to stimulating BDNF and its positive effects. And it seems likely that the greater the intensity and the more often you exercise, the more BDNF you produce. Dr Bredesen suggests combining aerobic exercise with weight training, preferably at least four or five times a week, for 45-60 minutes in total each day. Aim for 30 minutes to within 60-70pc of your maximum heart rate.

If you don’t immediately notice the benefits, don’t give up — one study showed that you need to keep exercising for at least five weeks to produce higher levels of BDNF. If you’re low in motivation, think about investing in a fitness tracker such as a Fitbit or Garmin to set targets and help track your heart rate and monitor your progress.