Memory Research News in Lifestyle

Greater muscle strength = better cognitive function

  • While handgrip strength has been linked to dementia risk in the elderly, a new study indicates that less impaired or fragile older adults need upper and lower body strength tests — but that these, too, are correlated with cognitive function.

A Finnish study involving 338 older adults (average age 66) has found that greater muscle strength is associated with better cognitive function.

Muscle strength was measured utilising handgrip strength, three lower body exercises such as leg extension, leg flexion and leg press and two upper body exercises such as chest press and seated row.

Handgrip strength, easy to measure, has been widely used as a measure of muscle strength, and has been associated with dementia risk among the very old. However, in this study, handgrip strength on its own showed no association with cognitive function. But both upper body strength and lower body strength were independently associated with cognitive function.

It may be that handgrip strength is only useful for older, more cognitively impaired adults.

These are gender-specific associations — muscle strength was significantly greater in men, but there was no difference in cognitive performance between men and women.

The finding is supported by previous research that found a link between walking speed and cognition in older adults, and by a 2015 study that found a striking correlation between leg power and cognition.

This 10-year British study involved 324 older female twins (average age 55). Both the degree of cognitive decline over the ten year period, and the amount of gray matter, was significantly correlated with high muscle fitness (measured by leg extension muscle power). The correlation was greater than for any other lifestyle factor tested

https://www.eurekalert.org/pub_releases/2017-06/uoef-gms062617.php

Reference: 

[4275] Pentikäinen H, Savonen K, Komulainen P, Kiviniemi V, Paajanen T, Kivipelto M, Soininen H, Rauramaa R. Muscle strength and cognition in ageing men and women: The DR's EXTRA study. European Geriatric Medicine [Internet]. 2017 ;8(3):275 - 277. Available from: http://www.sciencedirect.com/science/article/pii/S1878764917300712

[4076] Steves CJ, Mehta MM, Jackson SHD, Spector TD. Kicking Back Cognitive Ageing: Leg Power Predicts Cognitive Ageing after Ten Years in Older Female Twins. Gerontology [Internet]. 2015 . Available from: http://www.karger.com/?doi=10.1159/000441029

Brain tissue structure could explain link between fitness and memory

  • Brain scans of healthy young adults found that higher aerobic fitness was associated with greater hippocampal elasticity, which was a better predictor of cognitive performance than hippocampal volume.

A new MRI technique has revealed that it is the structural integrity of the hippocampus more than its size that reflects fitness and correlates with cognitive performance.

Research has focused on hippocampal size because it is easier to measure, and in children and older adults there are strong correlations between hippocampal size and memory. But this is less true for healthy, young adults. This new, subtler, technique reveals that something else is going on — something that has probably been masked by the effects of size in older adults (whose hippocampi are shrinking) and younger children (whose brains are still growing).

The technique measures viscoelasticity. If the hippocampus is more elastic, memory is better. When it’s more viscous, memory is worse. Those with better aerobic fitness had better hippocampal elasticity.

https://www.eurekalert.org/pub_releases/2017-05/uoia-bts050117.php

Reference: 

[4273] Schwarb H, Johnson CL, Daugherty AM, Hillman CH, Kramer AF, Cohen NJ, Barbey AK. Aerobic fitness, hippocampal viscoelasticity, and relational memory performance. NeuroImage [Internet]. 2017 ;153:179 - 188. Available from: http://www.sciencedirect.com/science/article/pii/S1053811917302859

Both aerobic exercise & strength training improves older brains

  • A review of research has confirmed the benefits of at least moderate exercise to fight age-related cognitive decline, with different benefits for aerobic exercise and strength training.

A review of 39 studies investigating the effect of exercise on cognition in older adults (50+) confirms that physical exercise does indeed improve cognitive function in the over 50s, regardless of their cognitive status. Aerobic exercise, resistance training, multicomponent training and tai chi, all had significant effects. However, exercise sessions needed to be at least 45  minutes and moderate intensity. Because aerobic exercise and resistance training had different effects (aerobic exercise helped overall cognition, while resistance training was particularly beneficial for executive function and working memory), it’s recommended that an exercise program include both.

https://medicalxpress.com/news/2017-04-aerobic-resistance-combo-boost-brain.html

Reference: 

[4272] Northey JMichael, Cherbuin N, Pumpa KLouise, Smee DJane, Rattray B. Exercise interventions for cognitive function in adults older than 50: a systematic review with meta-analysis. Br J Sports Med [Internet]. 2017 :bjsports - 2016-096587. Available from: http://bjsm.bmj.com/content/early/2017/03/30/bjsports-2016-096587

Even a single exercise session helps your brain

  • A review of research has concluded that even a single bout of physical activity can have significant positive effects on people's mood and cognitive functions.

An extensive review of research looking at the effects of a single bout of exercise has concluded that:

  • the most consistent behavioral effects of acute exercise are
    • improved executive function
    • enhanced mood
    • decreased stress levels
  • widespread brain areas and brain systems are activated

Executive functions include attention, working memory, problem solving, cognitive flexibility, verbal fluency, decision making, and inhibitory control.

These positive changes have been demonstrated to occur with very low to very high exercise intensities, with effects lasting for up to two hours after the end of the exercise bout.

While brainwaves are all enhanced across the brain, hippocampal theta brainwaves are particularly enhanced by exercise, and the effects of this suggest that exercise particularly helps with tasks that depend on hippocampal-prefrontal interactions. Exercise also helps increase blood flow to the frontal regions.

One of the most dramatic effects of exercise is on neurochemical levels, including neurotransmitters and growth factors (such as BDNF).

https://www.eurekalert.org/pub_releases/2017-06/ip-cas061217.php

Reference: 

[4271] Basso JC, Suzuki WA. The Effects of Acute Exercise on Mood, Cognition, Neurophysiology, and Neurochemical Pathways: A Review. Brain Plasticity [Internet]. 2017 ;2(2):127 - 152. Available from: http://content.iospress.com/articles/brain-plasticity/bpl160040

Aerobic exercise preserves brain volume and improves cognition in those with MCI

  • Regular exercise has been found to reduce brain shrinkage in those with mild cognitive impairment.

A study involving 35 adults with MCI found that those who exercised four times a week over a six-month period increased their volume of gray matter. But those who participated in aerobic exercise experienced significantly greater gains than those who just stretched, who also showed signs of white matter loss.

Aerobic activity included treadmill, stationary bike or elliptical training.

The study was presented at the annual meeting of the Radiological Society of North America (RSNA) in November, 2016.

https://www.eurekalert.org/pub_releases/2016-11/rson-aep111716.php

Exercise might help your vision

  • A small study found that low-intensity exercise significantly boosted activation in the visual cortex above what occurred during rest or high-intensity exercise.

A study involving 18 volunteers who performed a simple orientation discrimination while on a stationary bicycle, has found that low-intensity exercise boosted activation in the visual cortex, compared with activation levels when at rest or during high-intensity exercise.

The changes suggest that the neurons in the visual cortex were most sensitive to the orientation stimuli during the low-intensity exercise condition relative to the other conditions. It’s suggested that this reflects an evolutionary pressure for the visual system to be more sensitive when the individual is actively exploring the environment (as opposed to, say, running away).

http://www.futurity.org/vision-exercise-brains-1400422-2/

Reference: 

[4274] Bullock T, Elliott JC, Serences JT, Giesbrecht B. Acute Exercise Modulates Feature-selective Responses in Human Cortex. Journal of Cognitive Neuroscience [Internet]. 2016 ;29(4):605 - 618. Available from: http://www.mitpressjournals.org/doi/10.1162/jocn_a_01082