Do you ever have trouble remembering to go to the gym? It turns out that not only can exercise affect memory, but memory can also affect exercise.
Just 20 minutes of exercise can improve long-term memory for preceding events, researchers at Georgia Tech report.
How much of a memory enhancement? About 10 percent in healthy young adults.
There are many existing studies showing that months of aerobic exercises like running can improve memory. But this study took a unique approach.
Researchers had participants lift weights just once two days before testing them.
Participants also had to study events just before the exercise instead of after working out. Research suggests that the period after learning, known as consolidation, is when the stress caused by exercise is most likely to benefit memory.
“Our study indicates that people don’t have to dedicate large amounts of time to give their brain a boost,” said project lead Lisa Weinberg.
Episodic memory is associated with your brain’s frontal cortex and hippocampus. It is the type of memory that enables you to recall early childhood events, or what you had for supper last night.
“Remembrance of things past is not necessarily the remembrance of things as they were.” ― Marcel Proust
There are basically nine characteristics of episodic memory that distinguish it from other types of memory. Other types of memory may have a few of these properties, but only episodic memory has all nine:
- Contain summary records of sensory-perceptual-conceptual-affective processing.
- Retain patterns of activation/inhibition over long periods.
- Often represented in the form of (visual) images.
- They always have a perspective (field or observer).
- Represent short time slices of experience.
- They are represented on a temporal dimension roughly in order of occurrence.
- They are subject to rapid forgetting.
- They make autobiographical remembering specific.
- They are recollectively experienced when accessed.
Clocks, Waterslides and Mutilated bodies
The study started with all participants viewing a series of 90 photos on a computer screen. The images were split between positive (kids on a waterslide, for example), negative (mutilated bodies) and neutral (clocks).
Participants were not asked to remember the photos.
Everyone then sat at a leg extension resistance exercise machine.
Half of them extended and contracted each leg at their personal maximum effort 50 times. A control group just sat in the chair and allowed the machine and the experimenter to move their legs.
Participants came back to the lab 2 days later and saw a series of 180 pictures; the 90 originals were mixed in with 90 new photos.
The control group were able to recall about 50 percent of the photos from the first session. Those who exercised remembered about 60 percent.
In the study, weight exercises were used, but Weinberg notes that resistance activities such as squats or knee bends would probably give similar results. In other words, exercises that don’t require the person to be in good enough to shape to bike, run or participate in prolonged aerobic exercises.
Why does it Work?
Existing research has tied memory enhancements to acute stress responses, usually from psychological stressors such as public speaking.
Other studies have also linked particular hormonal and norepinephrine releases in rodent brains to better memory.
Its interesting that this new study showed exercise participants had increased saliva measures of alpha amylase, a marker of central norepinephrine.
“Even without doing expensive fMRI scans, our results give us an idea of what areas of the brain might be supporting these exercise-induced memory benefits,” said associate professor Audrey Duarte. “The findings are encouraging because they are consistent with rodent literature that pinpoints exactly the parts of the brain that play a role in stress-induced memory benefits caused by exercise.”
Motivating yourself to exercise can be a challenge, but memory may also help there. A study from earlier this year shows that simply remembering a positive memory about exercise may be just what it takes to get on the treadmill.
Researchers at the University of New Hampshire investigated the effects of remembering past exercise experience on college students’ subsequent exercise intentions and behaviors.
150 students were asked to recall either a positive or negative memory that would increase their motivation to exercise; other students were not asked to recall a motivational memory (the control group). The researchers then surveyed the students one week later to see if they reported an increase in exercise.
“The results provide the first experimental evidence that autobiographical memory activation can be an effective tool in motivating individuals to adopt healthier lifestyles," researchers wrote.
It was found that students who remembered a positive exercise memory reported significantly higher levels of later exercise than those who were not asked to recall a memory about exercise.
The researchers also found that students who were asked to recall a negative exercise memory also reported exercising more than the control group, although less than the group that recalled a positive exercise memory.
A single bout of resistance exercise can enhance episodic memory performance Lisa Weinberg, Anita Hasni, Minoru Shinohara Audrey Duarte Acta Psychologica, Volume 153 DOI: 10.1016/j.actpsy.2014.06.011
Conway M. A. (2009). Episodic Memory. Neuropsychologia, 47, 2305-2306
Smeets et al., 2008 True or false? Memory is differentially affected by stress-induced cortisol elevations and sympathetic activity at consolidation and retrieval Psychoneuroendocrinology, 33 (2008), pp. 1378–1386
Mathew J. Biondolillo, David B. Pillemer. Using memories to motivate future behaviour: An experimental exercise intervention. Memory, 2014; 1 DOI:10.1080/09658211.2014.889709