Study: Link Between Exercise And Genetic Effects Of Obesity Later In Life



A new study suggests - for the first time in women over age 70 - that working up a sweat can reduce the influence ones genes have on obesity. Our sample, which included older women, is the first to show that in the 70-to-79-year-old age group, exercise can mitigate the genetic effects of obesity, says the studys lead author Heather Ochs-Balcom, associate professor of epidemiology and environmental health in the University at Buffalos School of Public Health and Health Professions. The message here is that your genetic risk for obesity is not wholly deterministic. The choices we make in our life play a large role in our health.

The study - published recently in the journalMenopause - included researchers from UB, as well as the Fred Hutchinson Cancer Research Center; University of Wisconsin-Milwaukee; Rush University Medical Center; University of California, Davis; and The Ohio State University. Researchers studied 8,206 women of European ancestry who participated in the Womens Health Initiative. They used a larger set of 95 genetic polymorphisms to construct their body mass index genetic risk score to study the interaction between physical activity and obesity. Then, they evaluated whether genetic associations were modified by exercise and age.

The study revealed that genetic associations on body mass index or BMI were strongest in sedentary postmenopausal women and weakest in women who reported high levels of recreational physical activity. Our work suggests that in older age, we can overcome our destiny for obesity given to us by our parents through exercise, Ochs-Balcom said.

The study is significant in that, up to this point, little had been known about the effect of obesity genes later in life, particularly whether genetic predisposition can be mitigated by healthy behaviors such as physical activity. Its also one of a growing number of studies highlighting the benefits of being physically active, especially as it pertains to healthy aging. For the elderly, exercise is important for preventing muscle loss, which helps reduce the risk of falls, says Ochs-Balcom. Plus, there are many other benefits of exercise in older adults.

Older Obese Adults Can Benefit From Moderate Exercise

Moderate-intensity exercise can help even extremely obese older adults improve their ability to perform common daily activities and remain independent, according to researchers at Wake Forest Baptist Medical Center. Findings from the National Institutes of Health-funded study were published in the July 2018 issue of the journal Obesity. In the United States, obesity affects nearly 13 million adults age 65 and older. Both overall obesity and abdominal obesity are strongly associated with the development of major mobility disability (MMD), the inability to walk a quarter of a mile, according to the studys lead author, Stephen Kritchevsky, Ph.D., director of the Sticht Centerfor Healthy Aging and Alzheimer's Preventionat Wake Forest Baptist.

Previous data on older populations had suggested that obesity may lessen the beneficial effects of physical activity on mobility. However, this research, which analyzed data from the multicenter Lifestyle Interventions and Independence for Elders (LIFE) study, showed that a structured physical activity program reduced the risk of MMD even in older adults with extreme obesity. The LIFE study was the first to demonstrate that moderate intensity physical activity can significantly reduce the risk of MMD in sedentary older adults. The inability to walk a quarter of a mile is a proxy for common daily activities, such as the inability to walk a block around the neighborhood or to walk several street blocks to go to a store, Kritchevsky said. Having a major mobility disorder can really affect the quality of life and independence for older people, but we showed that moderate exercise was a safe and effective way to reduce that risk even in severely obese people.

The LIFE study enrolled 1,635 sedentary men and women age 70 to 89. The participants were randomized to a moderate intensity physical activity program or a health education program to test if the physical activity program would reduce the rate of MMD compared to the education program. Major mobility disability was defined as the inability to walk 400 meters - about a quarter of a mile - without sitting and without help from another person or a walker. Participants were divided into four groups according to BMI a measure of body fat based on height and weight and waist circumference: non-obese with BMI less than 30; non-obese with high waist circumference of more than 40 inches for men and 34 inches for women; class 1 obese with BMI between 30 and 35; and class 2 obese with BMI of 35 or higher.

The physical activity program focused on walking, strength, balance and flexibility training. The goal for participants was to be able to walk at moderate intensity for 30 minutes and perform 10 minutes of lower-extremity strength training with ankle weights and 10 minutes of balance training in a single session. Participants attended two center-based training sessions per week and performed at-home activities three to four times per week during the two-year study.

The health education program involved in-person group workshops focused on aging-relevant topics such as nutrition, safety and legal/financial issues. Sessions included lectures and interactive discussions and five to 10 minutes of upper body stretching exercises. While there was no significant difference between obesity category and intervention effect, those in the class 2 obesity group showed the greatest benefit from the physical activity program, reducing their risk of MDD by 31 percent.

Customized Resistance Exercise And Fibromyalgia

Fibromyalgia and resistance exercise have often been considered an impossible combination, but with proper support and individually adjusted exercises, female patients achieved considerable health improvements, according to research at Sahlgrenska Academy in Sweden. "If the goal for these women is to improve their strength, then they shouldn't be afraid to exercise, but they need to exercise the right way, says Anette Larsson, an active physical therapist. It has long been said that they will only experience more pain as a result of resistance exercise, that it doesn't work. But in fact, it does.

Larsson studied 130 women between the ages of 20 and 65 years with fibromyalgia, a disease in which nine of 10 cases are women. It is characterized by widespread muscle pain and increased pain sensitivity, often combined with fatigue, reduced physical capacity and limitation of activities in daily life. About half of the women in the study were selected at random to undergo a program of person-centered, progressive resistance exercise led by a physical therapist. The other 63 women comprised the control group and underwent a more traditional therapy program with relaxation exercises. The training and exercises lasted for 15 weeks and were held twice a week.

"The women who did resistance exercise began at very light weights, which were determined individually for each participant because they have highly varying levels of strength, Larsson said. We began at 40 percent of the max and then remained at that level for three to four weeks before increasing to 60 percent. More than six of 10 women were able to reach a level of exercise at 80 percent of their maximum strength. One of the 10 was at 60 percent and the others were below that figure. Five individuals chose to stop the training due to increased pain. The group as a whole had 71 percent attendance at the exercise sessions.

"On a group level, the improvements were significant for essentially everything we measured, Larsson continued. The women felt better, gained muscle strength, had less pain, better pain tolerance, better health-related quality of life and less limitation of activities. Some of the women did not manage the exercise and became worse, which is also an important part of the findings. In the control group, the improvements were not as significant, but even there, hand and arm strength improved. The relaxation exercises probably led to reduced muscle tension in the arms and shoulders, which in turn allowed the participants to develop more strength.

The findings for the women in the resistance exercise group are affected by several factors, including the degree of pain and fear of movement before and during the exercise period. Progress for the group as a whole can largely be attributed to the person-centered approach, with individually adjusted exercises and loads and support of a physical therapist. "An interview study we conducted shows clearly that the women need support to be able to choose the right exercises and the right loads; they also need help when pain increases, Larsson said. This requires, quite simply, support from someone who knows their disease, preferably a physical therapist."

Should You Eat Before Exercising

A study conducted by researchers from the University of Bath in the United Kingdom is the first of its kind to show the effects of eating versus fasting on gene expression in adipose (fat) tissue in response to exercise. This studyhighlights the different roles fat plays in powering and responding to exercise.The study, published in theAmerican Journal of PhysiologyEndocrinology and Metabolism, monitored a group of overweight males. The volunteers walked for 60 minutes at 60 percent maximum oxygen consumption on an empty stomach and, on another occasion, two hours after consuming a high-calorie carbohydrate-rich breakfast. The research team took multiple blood samples after eating or fasting and after exercising. The researchers also collected adipose tissue samples immediately before and one hour after walking.

Gene expression in the adipose tissue differed significantly in the two trials. The expression of two genes - PDK4 and HSL - increased when the men fasted and exercised and decreased when they ate before exercising. The rise in PDK4 likely indicates that stored fat was used to fuel metabolism during exercise instead of carbohydrates from the recent meal. HSL typically increases when adipose tissue uses stored energy to support increased activity, such as during exercise. These results reinforce the view that adipose tissue often faces competing challenges, says Dylan Thompson, corresponding author of the study. After eating, adipose tissue is busy responding to the meal and a bout of exercise at this time will not stimulate the same [beneficial] changes in adipose tissue. This means that exercise in a fasted state might provoke more favorable changes in adipose tissue, and this could be beneficial for health in the long term.

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