Study: Regular Exercise at Any Age Might Stave Off Alzheimer’s

Fitness Level Correlates with Increased Blood Flow to Essential Areas of the Brain

Newswise , May 17, 2016-- Recent research suggests that exercise might provide some measure of protection from Alzheimer’s disease and other dementias.

A group of researchers led by Nathan Johnson PT, DPT, PhD of the University of Kentucky College of Health Sciences, was able to demonstrate a positive correlation between fitness and blood flow to areas of the brain where the hallmark tangles and plaques of AD pathology are usually first detected.

Thirty men and women ages 59-69 were put through treadmill fitness assessments and ultrasounds of the heart. Then they received brain scans to look for blood flow to certain areas of the brain.

“We set out to characterize the relationship between heart function, fitness, and cerebral blood flow, which no other study had explored to date,” Johnson said.

“In other words, if you’re in good physical shape, does that improve blood flow to critical areas of the brain? And does that improved blood flow provide some form of protection from dementia?”

The results showed blood flow to critical areas of the brain – and so the supply of oxygen and vital nutrients – was higher in those who were more physically fit.

In layman’s terms, this study demonstrates that regular exercise at any age could keep the mind young, according to Johnson.

“Can we prove irrefutably that increased fitness will prevent Alzheimer’s disease? Not at this point,” Johnson said.

“But this is an important first step towards demonstrating that being physically active improves blood flow to the brain and confers some protection from dementia, and conversely that people who live sedentary lifestyles, especially those who are genetically predisposed to Alzheimer’s, might be more susceptible.”

Since people who exercise frequently often have reduced arterial stiffness, Johnson and his group postulate that regular physical activity – regardless of age – maintains the integrity of the “pipes” that carry blood to the brain.

“In the mid-late 20th century, much of the research into dementias like Alzheimer’s focused on vascular contributions to disease, but the discovery of amyloid plaques and tangles took prevailing research in a different direction” Johnson said.

“Research like this heralds a return to the exploration of the ways the vascular system contributes to the disease process.”

Johnson’s research, which was supported by a grant from the National Institutes of Health CTSA (UL1TR000117) and the University of Kentucky's Clinical Services Core, was published in the current issue of NeuroImage.

Supplements, Exercise Could Improve Muscle Mass and Strength for Older Adults

Rick Sharp is working with older adults to see if a combination of supplements and resistance training can slow the progression of sarcopenia.
Photo by Christopher Gannon, Iowa State University

September 3, 2015– The loss of muscle strength and function, what’s known as sarcopenia, is a natural part of aging. It’s also a growing public health concern because of the risk for falls, injury and decline in quality of life. That’s why an Iowa State University researcher is working to slow or reverse the progression of sarcopenia.

Rick Sharp, a professor of kinesiology, is testing the effectiveness of a combination of supplements and resistance training in older adults with low vitamin D levels. 

The trial is designed to build on previous studies, which show that the supplement HMB reduces muscle loss. HMB, or b-hydroxy-b-methylbutyrate, is a natural body building compound discovered by Iowa State researchers.

However, not everyone in those studies benefited equally from HMB and weight training, Sharp said. Researchers determined older adults who didn’t respond as well to the supplement had something in common – lower levels of vitamin D.

Sharp says lower vitamin D is common in climates in which people do not get year-round exposure to the sun. Both HMB and vitamin D are in foods we normally eat and available as supplements. The goal of the study is to see if vitamin D will improve response to HMB and resistance training, increasing muscle mass and strength.

“We know that sarcopenia is so predictable in older adults that anything we can do that slows down the progression and/or reverses it, is going to be effective,” Sharp said. 

“If all we were to do is prevent their muscle mass and function from dropping, we’ve already had a real positive impact. Even if it doesn’t improve by 10, 15, 20 percent, they’re not losing it and that’s just as good.”

No magic pill

Sharp stresses the importance of exercise and resistance training as we age. It’s not just aging that contributes to sarcopenia, he said, it’s aging and reduced activity. His research on vitamin D and HMB is intended to boost exercise results by providing appropriate nutritional support, not create a magic pill.

“There’s no substitute for physical activity. We have to stay physically active through the lifespan,” Sharp said. 

“We think nutrition is a key component in helping to ensure that older adults get a better response from exercise.”

To monitor response, some study participants will continue with their normal exercise and daily routine. Others will attend on-campus exercise sessions, designed and conducted by ISU researchers. 

Sharp says the workouts incorporate resistance bands and weight machines, and target all major muscle groups to improve balance and strength.

“As we get older our activities of daily living really depend on proper functioning of all those muscle groups working together,” Sharp said. 

“We’re really cognizant of the risk of falls with the older individuals. One way to reduce falls and injury from falls is to improve balance and coordination and the ability to catch yourself when you stumble. That requires good reaction time and the ability to generate the amount of force to catch yourself before you tumble.”

Participants still needed

These changes won’t happen overnight, which is why researchers will track each individual’s muscle mass and strength for a year. Sharp says it will take several years to complete the testing before he can analyze the results. A total of 160 participants – 80 men and 80 women – are needed for the study. 

Why Does Running Make Us Happy?

Newswise, September 2, 2015 — The joy of running. That sense of well-being, freedom and extra energy that runners often experience is not just a matter of endorphins. A study at the University of Montreal Hospital Research Centre (CRCHUM) shows that the "runner’s high" phenomenon is also caused by dopamine, an important neurotransmitter for motivation.

"We discovered that the rewarding effects of endurance activity are modulated by leptin, a key hormone in metabolism. Leptin inhibits physical activity through dopamine neurons in the brain", said Stephanie Fulton, a researcher at the CRCHUM and lead author of an article published today in the journal Cell Metabolism.

Secreted by adipose tissue, leptin helps control the feeling of satiety. This hormone also influences physical activity. 

"The more fat there is, the more leptin there is and and the less we feel like eating. Our findings now show that this hormone also plays a vital role in motivation to run, which may be related to searching for food", explained Stephanie Fulton, who is also a professor at Université de Montréal’s Department of Nutrition.

Hormone signals that modulate feeding and exercise are in fact believed to be closely linked. Endurance running capacity in mammals, particularly humans, is thought to have evolved to maximize the chances of finding food. 

This study suggests that leptin plays a critical role both in regulating energy balance and encouraging behaviours that are "rewarding" for the person’s metabolism, i.e., engaging in physical activity to find food.

The researchers studied voluntary wheel running in mice in cages. These mice can run up to seven kilometres a day. 

In a laboratory, the physical activity of normal mice was compared with that of mice who underwent a genetic modification to suppress a molecule activated by leptin, STAT3 (signal transducer and activator of transcription-3). The STAT3 molecule is found in the neurons that synthesize dopamine in the midbrain. 

This “mesolimbic dopaminergic pathway” is a like a motivational highway in the brain.

"Mice that do not have the STAT3 molecule in the dopaminergic neurons run substantially more. 

Conversely, normal mice are less active because leptin then activates STAT3 in the dopamine neurons, signalling that energy reserves in the body are sufficient and that there is no need to get active and go looking for food", explained Maria Fernanda Fernandes, first author of the study.

And is leptin as important for motivation to be active in humans? Yes. 

"Previous studies have clearly shown a correlation between leptin and marathon run times. The lower leptin levels are, the better the performance. Our study on mice suggests that this molecule is also involved in the rewarding effects experienced when we do physical exercise. 

"We speculate that for humans, low leptin levels increase motivation to exercise and make it easier to get a runner’s high", summed up Stephanie Fulton.

Mice, humans and mammals in general are thought to have evolved to increase the return on effective food acquisition behaviours. Ultimately, hormones are sending the brain a clear message: when food is scarce, it’s fun to run to chase some down.

About the study

The study “Leptin suppresses the rewarding effects of running via STAT3 signaling in dopamine neurons” was published in Cell Metabolism. Financial support: Stephanie Fulton is a recipient of a Canadian Institutes of Health Research New Investigator Salary Award; Thierry Alquier is a recipient of a salary award from the Fonds de recherche du Québec – Santé (FRQS); Maria Fernanda Fernandes, now a post-doctoral fellow at the University of Guelph (Ontario), is a recipient of a doctoral fellowship from the Canadian Diabetes Association and the Department of Physiology, Université de Montréal.

The other authors are: Dominique Matthys, Cécile Hryhorczuk, Sandeep Sharma and Shabana Mogra. To find out more, see the study at this link:
http://www.cell.com/cell-metabolism/abstract/S1550-4131(15)00394-0