Is It Harder to Lose Weight When You’re Older?

By Karen Weintraub, NY Times, March 31, 2017

Q. Is it more difficult for an older person to lose weight?

A. Yes, unfortunately. Although it is possible to lose weight at any age, several factors make it harder to lose weight with age.

Even those who remain active lose muscle mass every decade beginning in their 30s, research suggests, replacing it with fat. Muscles use up more calories than fat, so less muscle means a slower metabolism and the need for fewer calories, said Dr. Medha Munshi, a geriatrician and endocrinologist at Beth Israel Deaconess Medical Center in Boston.

Declining levels of the sex hormones estrogen and testosterone, which typically start around the early 50s for women, with the onset of menopause, and somewhat later for men, compound the effect, said Dr. Munshi, who also directs the Joslin Diabetes Center’s geriatric diabetes programs.

People may also pay in late-middle age for weight they gained and lost in earlier decades, said Dr. Leslie Cho, an interventional cardiologist at the Cleveland Clinic. Weight gain changes metabolism, she said. A 60-year-old who now weighs 200 pounds but once weighed 300, for example, will need far fewer calories per day than someone of the same age and size who was never so overweight. Losing those fat cells, she explained, tricks the body into thinking it is starving and needs to hold on more tightly to calories consumed. “You do have to eat less to maintain that weight if you’ve been heavy,” said Dr. Cho, who also directs the Cleveland Clinic’s Women’s Cardiovascular Center. .

Older people also tend to have more aches and pains and to be more sedentary, engaging in fewer physical activities.

Instead of obsessing about a number on a scale, Dr. Cho suggests that older people focus on general fitness. “It’s not about losing weight,” she said. “It’s about maintaining weight loss, but also about healthy eating and lifestyle.”

Adding muscle through weight training can also help speed up metabolism, or at least compensate somewhat for its decline, Dr. Munshi said. She tells her older patients that “you need it now more than you needed it at 25.” Eating more protein–but not more calories–may also help build or sustain muscle, she said. And she noted that many of her oldest patients end up underweight because they’ve lost their appetite along with their sense of smell, so food doesn’t seem appealing anymore.

Read More

Getting a Brain Boost Through Exercise

By Gretchen Reynolds, NY Times, April 10, 2013
Two new experiments, one involving people and the other animals, suggest that regular exercise can substantially improve memory, although different types of exercise seem to affect the brain quite differently. The news may offer consolation for the growing numbers of us who are entering age groups most at risk for cognitive decline.

It was back in the 1990s that scientists at the Salk Institute for Biological Studies in La Jolla, Calif., first discovered that exercise bulks up the brain. In groundbreaking experiments, they showed that mice given access to running wheels produced far more cells in an area of the brain controlling memory creation than animals that didn’t run. The exercised animals then performed better on memory tests than their sedentary labmates.

For the human study, published in The Journal of Aging Research, scientists at the University of British Columbia recruited dozens of women ages 70 to 80 who had been found to have mild cognitive impairment, a condition that makes a person’s memory and thinking more muddled than would be expected at a given age.

Earlier, the same group of researchers had found that after weight training, older women with mild cognitive impairment improved their associative memory, or the ability to recall things in context—a stranger’s name and how you were introduced, for instance.

Now the scientists wanted to look at more essential types of memory, and at endurance exercise as well. So they randomly assigned their volunteers to six months of supervised exercise. Some of the women lifted weights twice a week. Others briskly walked. And some, as a control measure, skipped endurance exercise and instead stretched and toned.

At the start and end of the six months, the women completed a battery of tests designed to study their verbal and spatial memory. Verbal memory is, among other things, your ability to remember words, and spatial memory is your remembrance of where things once were placed in space. Both deteriorate with age, a loss that’s exaggerated in people with mild cognitive impairment.

And in this study, after six months, the women in the toning group scored worse on the memory tests than they had at the start of the study. Their cognitive impairment had grown.

But the women who had exercised, either by walking or weight training, performed better on almost all of the cognitive tests after six months than they had before.

There were, however, differences. While both exercise groups improved almost equally on tests of spatial memory, the women who had walked showed greater gains in verbal memory than the women who had lifted weights.

What these findings suggest, the authors conclude, is that endurance training and weight training may have different physiological effects within the brain and cause improvements in different types of memory.

That idea tallies nicely with the results of the other recent study of exercise and memory, in which lab rats either ran on wheels or, to the extent possible, lifted weights. Specifically, the researchers taped weights to the animals’ tails and had them repeatedly climb little ladders to simulate resistance training.

After six weeks, the animals in both exercise groups scored better on memory tests than they had before they trained. But it was what was going on in their bodies and brains that was revelatory. The scientists found that the runners’ brains showed increased levels of a protein known as BDNF, or brain-derived neurotrophic factor, which is known to support the health of existing neurons and coax the creation of new brain cells. The rat weight-trainers’ brains did not show increased levels of BDNF.

The tail trainers, however, did have significantly higher levels of another protein, insulinlike growth factor, in their brains and blood than the runners did. This substance, too, promotes cell division and growth and most likely helps fragile newborn neurons to survive.

What all of this new research suggests, says Teresa Liu-Ambrose, an associate professor in the Brain Research Center at the University of British Columbia who oversaw the experiments with older women, is that for the most robust brain health, it’s probably advisable to incorporate both aerobic and resistance training. It seems that each type of exercise “selectively targets different aspects of cognition,” she says, probably by sparking the release of different proteins in the body and brain.

But, she continues, no need to worry if you choose to concentrate solely on aerobic or resistance training, at least in terms of memory improvements. The differences in the effects of each type of exercise were subtle, she says, while the effects of exercise—any exercise—on overall cognitive function were profound.

Read More