When you do a single session of resistance exercise, your muscles grow a little. Overall, it takes a couple of days.

As you lift weights, muscle fibres suffer micro-tears. Part of the healing process involves an emergency dose of nutrition.

A new study finds that the brain’s connectivity and memory function are also improved by a single session of high-intensity resistance training.

These improvements became apparent within a couple of days.

Study participants did better on memory tests. And MRI scans revealed improved functional connectivity within the hippocampus, a brain region crucial for memory formation.

The Tohoku University study is supported by a body of research confirming a link between exercise, memory and the hippocampus.

The hippocampus is part of the brain’s limbic system, the different parts of which support emotion, behaviour, long-term memory and our sense of smell.

The hippocampus is part of the brain’s limbic system. Photo: Getty

The brain has two hippocampi, each of them shaped like a seahorse. They’re involved in memory, learning and emotion.

The hippocampus is one of the most studied parts of the brain because of its involvement in many neurological conditions and diseases. It is especially vulnerable to damage.

The hippocampus holds short-term memories and transfers them to long-term storage in our brains. It also plays a role in emotional processing, including anxiety and avoidance behaviours.

A 2010 study found an association between physical fitness and the brain in nine- and 10-year-old children. Those who are more fit tend to have a bigger hippocampus and perform better on a test of memory than their less-fit peers.

A 2017 study found that physical exercise has an anti-ageing effect on the hippocampus.

When comparing different forms of exercise – dancing and endurance training – undertaken by elderly volunteers for 18 months, both have an anti-ageing effect on the brain, but only dancing corresponded to a noticeable difference in behaviour.

This difference is attributed to the extra challenge of learning dancing routines.

A 2018 study found that running helps brain stave off effects of chronic stress on the hippocampus. This protects vital memory and learning functions.

The new study

According to PsyPost, 60 healthy young adults, who did no regular resistance training, were recruited.

These participants, comprising both men and women aged 19 to 27, were divided into a training group and a control group.

The training group underwent a session of muscle strength training, while the control group did not engage in any muscle training.

Participants’ memory performance were measured with free recall and cued recall tests conducted before and two days after the exercise session.

In a free recall test, a participant recalls a list of items in any order. This task resembles memorising items on a shopping list.

In a cued recall test, participants retrieved information from long-term memory using aids or cues, such as words or incomplete pictures.

In the study, magnetic resonance imaging (MRI) was used to examine hippocampal functional connectivity.

The MRI data revealed “increased connectivity between certain regions of the hippocampus and other parts of the brain in the training group”.

This enhanced connectivity “was associated with the observed improvements in memory performance, supporting the hypothesis that resistance training can positively affect the brain’s memory-related networks”.

The results also showed “significant improvements in memory performance in the training group compared to the control group”.

Namely by recalling a higher percentage of words from a list they had learned two days earlier.

Study author Teruo Hashimoto, an assistant professor of functional brain imaging at Tohoku University, said the findings indicate that “a single bout of resistance training can be effective in improving memory and brain function after a few days”.

He noted: “memory enhancement detected in this study was statistically significant but very small”.