Sydney, Nov 15 (IANS): Are you having difficulty in memorising phone numbers or other valuable data for long term use? You need to start exercising to improve your memory functioning.

Indulging in aerobic exercises can help you increase the brain size that further enhances the memory function and maintains a good brain health, says a new research.

The brain health decreases with age, with the average brain shrinking by approximately five per cent after the age of 40, as mentioned in the study, published in the journal Neuroimage.

Aerobic exercises can help a particular region of the brain called the hippocampus, which is critical for memory and other brain functions. It may also prevent ageing-related neurodegenerative disorders such as Alzheimer's and dementia, the researcher noted.

"When you exercise, you produce a chemical called brain-derived neurotrophic factor, which may help to prevent age-related decline by reducing the deterioration of the brain," said Joseph Firth, researcher at the Western Sydney University in Australia.

The researchers reviewed 14 clinical trials, which examined the brain scans of 737 people before and after aerobic exercise programs.

The participants, aged between 24 to 76 years, included a mix of healthy adults, people with mild cognitive impairment such as Alzheimer's and people with a clinical diagnosis of mental illness including depression and schizophrenia.

The researchers examined effects of aerobic exercise, including stationary cycling, walking, and treadmill running. The length of the interventions ranged from three to 24 months with a range of 2-5 sessions per week.

The results showed that while exercise had no effect on total hippocampal volume, it did significantly increase the size of the left region of the hippocampus in humans.