Both the men and the women laid down belly fat. "We studied postmenopausal women, so they were gaining visceral fat aggressively," he notes. Before you know it, your slacks are snug.
"People don't realize that inactivity is not a steady state," says Slentz. "They think it would be nice to start exercising, but if they think about it for six months, they've gained another pound. or two and an 8 percent increase in visceral fat."
How much activity is enough to stop gaining? It depends on who you are.
"If you're trying not to become overweight or obese, it looks like 45 to 60 minutes a day," says Harvard's I-Min Lee. But the story is different for people who used to be chubby.
"Individuals who are overweight and have lost weight need more physical activity to maintain the weight loss than people who don't want to gain weight, because if you've already become overweight, you're in an at-risk group," she notes. "Those people probably need 60 to 90 minutes a day to avoid regaining weight."
If that sounds about as realistic as going to medical school in your spare time, don't despair. "That's based on formerly obese individuals who lost 30 to 50 pounds and kept it off," says Blair. "You don't need 90 minutes a day to keep five pounds off."
What's more, it's not as though half an hour a day doesn't count. "Just 30 minutes a day is sufficient to reduce the risk of many chronic diseases," says Lee.
10 Immune System
Regular exercise may boost the immune system ... unless you overdo it. One indicator: how often people get colds.
"In moderate amounts, physical activity reduces the risk of upper respiratory tract infection," says Lee.
In studies that use older or middle-aged individuals, 30 to 45 minutes of walking about five days a week is moderate, she adds.
But the tables are turned if you go to extremes.
"Marathon runners have a higher risk of colds after a race, because immune function goes down after a prolonged intense bout of exercise," says Lee.
The picture is similar for inflammation, which can be a sign of weakened immune function.
"It's very complicated, but it looks like regular exercise can decrease inflammation," says the University of Maryland's Ben Hurley.
On the other hand, playing a hard game of basketball or soccer once a month can boost inflammation if that's all you do.
"The weekend athlete who does something strenuous once in a while can do more harm than good to a lot of systems," says Hurley. "You have to perform vigorous activity at least two or three times a week to avoid making things worse."
The Bottom Line
* To lower your risk of heart disease, diabetes, and colon cancer, shoot for at least 30 minutes a day of moderate-intensity aerobic exercise like brisk walking, cycling, jogging, or swimming.
* To keep off substantial amounts of lost weight, shoot for 60 to 90 minutes a day of moderate-intensity aerobic exercise.
* To build muscle and prevent bone loss, do strength training exercises at least twice a week using weights you can lift no less than 8--but no more than 15--times.
Showing posts with label strength training exercises. Show all posts
Showing posts with label strength training exercises. Show all posts
Thursday, July 2, 2009
page 4 - Inactivity
You can't easily get tested to see if you have the gene variations that make blood pressure respond to regular exercise. But that shouldn't keep you off your feet, says Hurley.
"You may not respond with lower blood pressure, but you may improve more than others in other areas such as insulin sensitivity," he explains. "We've never seen a case where someone doesn't have the right genotype for any benefit."
6 Muscles
It happens earlier in women than in men, but in both genders muscle starts to wither away if it's not used.
"Muscle atrophy for people with average activity levels starts at age 40 for women and in the late 50s for men," says Hurley. The muscle wasting probably starts even earlier, he adds, but so slowly that it isn't easy to detect.
"For every decade after about age 50, you lose some 6 percent of your muscle mass, which comes with a 10 to 15 percent loss of your strength," says Hurley.
But anyone can build muscle back up with strength training exercises. (11) "After two months of training, we see a 40 percent increase in strength," says Hurley.
"The earlier you start, the better," he adds. "But even people over 100 years old can partially reverse some of the loss that occurs with aging."
The trick is to not just use the muscle, but to overload it. "You have to make it work harder than it's accustomed to," explains Hurley.
"If you overload it in a gradual, progressive way, you can make the muscles bigger and stronger by making each muscle fiber thicker."
If you think of strong muscles as a luxury, think again. They can ward off the frailty that makes older people lose their independence, either because they can't take care of themselves or because they fall and fracture a hip.
"Regular exercise is the best way to stay out of a nursing home," says the Cooper Institute's Steven Blair.
7 Bones
Fragile bones--osteoporosis--cause more than 1.5 million fractures each year in the U.S. But bone starts to disintegrate decades before it cracks.
"Bone is like any other part of your body," says Harvard's I-Min Lee. "If you stress it, it responds."
If you don't, the ongoing balance between bone buildup and breakdown shifts towards a net loss. But strength training can make a difference.
"The research doesn't consistently show that you can increase bone, but you can prevent loss," says Hurley.
The best studies randomly assign people to strength training or a non-training "control" group. (12) "In postmenopausal women, the control group loses almost 1 percent of their bone mineral density in a year," notes Hurley. "But the group that trains either stays the same or has a slight increase."
Whether you actually gain bone or hold on to it may depend on how much you stress, or overload, the bone.
"We reported a 3 percent increase in density in the femoral neck bone at the top of the thigh, we think because the leg press--an exercise that strengthens the major leg muscles--has the greatest load," says Hurley. "We didn't see an increase where the load wasn't very big."
"You may not respond with lower blood pressure, but you may improve more than others in other areas such as insulin sensitivity," he explains. "We've never seen a case where someone doesn't have the right genotype for any benefit."
6 Muscles
It happens earlier in women than in men, but in both genders muscle starts to wither away if it's not used.
"Muscle atrophy for people with average activity levels starts at age 40 for women and in the late 50s for men," says Hurley. The muscle wasting probably starts even earlier, he adds, but so slowly that it isn't easy to detect.
"For every decade after about age 50, you lose some 6 percent of your muscle mass, which comes with a 10 to 15 percent loss of your strength," says Hurley.
But anyone can build muscle back up with strength training exercises. (11) "After two months of training, we see a 40 percent increase in strength," says Hurley.
"The earlier you start, the better," he adds. "But even people over 100 years old can partially reverse some of the loss that occurs with aging."
The trick is to not just use the muscle, but to overload it. "You have to make it work harder than it's accustomed to," explains Hurley.
"If you overload it in a gradual, progressive way, you can make the muscles bigger and stronger by making each muscle fiber thicker."
If you think of strong muscles as a luxury, think again. They can ward off the frailty that makes older people lose their independence, either because they can't take care of themselves or because they fall and fracture a hip.
"Regular exercise is the best way to stay out of a nursing home," says the Cooper Institute's Steven Blair.
7 Bones
Fragile bones--osteoporosis--cause more than 1.5 million fractures each year in the U.S. But bone starts to disintegrate decades before it cracks.
"Bone is like any other part of your body," says Harvard's I-Min Lee. "If you stress it, it responds."
If you don't, the ongoing balance between bone buildup and breakdown shifts towards a net loss. But strength training can make a difference.
"The research doesn't consistently show that you can increase bone, but you can prevent loss," says Hurley.
The best studies randomly assign people to strength training or a non-training "control" group. (12) "In postmenopausal women, the control group loses almost 1 percent of their bone mineral density in a year," notes Hurley. "But the group that trains either stays the same or has a slight increase."
Whether you actually gain bone or hold on to it may depend on how much you stress, or overload, the bone.
"We reported a 3 percent increase in density in the femoral neck bone at the top of the thigh, we think because the leg press--an exercise that strengthens the major leg muscles--has the greatest load," says Hurley. "We didn't see an increase where the load wasn't very big."
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