Strongwomen.com - Your Virtual Trainer with Dr. Miriam Nelson

If you have school-age children, your family - like mine - is probably shifting into summer gear. Suddenly the kids have plenty of free time. And maybe they're perfectly happy to spend the whole day in front of the TV or computer monitor. But it's so important for a child's day to include plenty of physical activity. It's not just a matter of their health, though of course that's one benefit. As I'm sure you've noticed, kids are happier when they're active.

One of the best ways to ensure that youngsters get plenty of exercise is to plan family activities like swimming, biking, and boating. That's good for you too. Think back to your childhood summers, and dust off old favorites. Do you have a badminton set in the attic? Have you practiced shooting baskets lately? How about paddling around a lake in a canoe?

I've been enjoying evening runs even more now that one of my kids accompanies me on a bike. Our family spends weekends and vacation time in New Hampshire, and we try to hike in the mountains at least once a week. Often we're joined by friends and cousins - it's a great way to socialize as a family.

Last month's newsletter answered a question from a reader who had heard that carbonated beverages are harmful to bones. I replied that there's no evidence of such a danger - so long as healthy drinks, like milk or fruit juice, aren't replaced by the empty calories of sugary sodas. Many readers wrote to say that they'd heard otherwise. This query was typical:

"Rumor in the health-conscious community has it that the phosphorus in carbonated beverages interferes with the body's proper absorption of calcium. Is this not true?"

Indeed, this is not true. Because there's widespread misinformation about soda and phosphorus, I want to provide a fuller answer.

Phosphorus is an essential mineral, one of the body's building blocks for bone. The Dietary Reference Intake (DRI) for phosphorus is 700 mg per day for adult women. Though many women don't get enough calcium in their diet, insufficient phosphorus is seldom a problem because phosphorus is abundant in many common foods. But calcium metabolism can suffer when you consume considerably more phosphorus than calcium. This is because both calcium and phosphorus require vitamin D for proper metabolism. If there's an excess of phosphorus, less vitamin D is available for processing calcium, so calcium absorption is reduced.

Could soda consumption cause a phosphorus excess? Very unlikely. Many sodas have no phosphorus at all - and even those that do contain phosphorus have modest amounts compared to other common foods.

There's no phosphorus at all in club soda or seltzer, according to the USDA Nutrient Database for Standard Reference (1998). Sodas that do have phosphorus contain well less than 100 milligrams per 8-ounce serving. Here are a few typical examples:

To put these quantities in perspective, let's look at some other foods. Among the most significant sources of phosphorus in the typical American diet are whole grains (including cereal), meat, poultry and dairy foods. Some examples:

In other words, you'd have to drink more than two six-packs of Diet Coke to ingest as much phosphorous as you'd get from a modest serving of All Bran and skim milk.

Reducing soda consumption to avoid phosphorus is like cutting back on carrots to save calories: Yes, carrots provide calories - but they're very unlikely to be a significant source of excess calories in your diet.

Finally, there are two legitimate bone-related concerns involving soda. One, which I mentioned last month, is that some people - especially teenagers - may drink soda instead of milk and consequently they don't get enough calcium.

The other possible issue is caffeine, an ingredient in many colas and other sodas. Caffeine has a diuretic effect and can interfere with calcium absorption if you consume more than 400 milligrams per day (the equivalent of about four cups of coffee). If you're already close to that limit with coffee, and also drink several glasses of caffeine-containing soda daily, you might want to cut back or switch to decaffeinated. Typically, sodas that contain caffeine have about as much as teas that contain caffeine - considerably less than coffee. But check the label for exact amounts. For example, an 8-ounce glass of regular Coca-Cola contains 31 milligrams of caffeine; there's none in the caffeine-free version.

Q: My 13-year-old daughter really wants to follow the strength training program with me. I know I've read that strength training for young boys can be detrimental. My daughter is fairly physically mature. Do you have any advice or caution?

A: We get questions like this frequently - sometimes for younger or older children. So I'm going to give a long answer that covers kids of all ages.

Youngsters can benefit from appropriate strengthening exercise. What's appropriate depends on their age. The American Academy of Pediatrics does not recommend that children under age 10 use free weights or exercise machines. That's because kids are more prone to injury than adults are - they might drop or trip over the weights; they tend to get impatient and do the moves too quickly. But boys and girls under age 10 can do strengthening exercises that use body weight: sit-ups, push-ups, pull-ups, stationary jumps, and hill runs.

New evidence suggests that children older than 10 can safely strength train with equipment, and will gain important benefits: increased muscle strength and muscle mass, plus improved general fitness. The National Strength and Conditioning Association recently published these safety guidelines for older children who do strength training:

If your daughter wants to train with you - and you are confident that she is mature enough to follow your instructions - this can be a great activity for both of you. Be sure to teach her all the safety guidelines (breathing properly, stowing the weights, lifting smoothly and slowly, etc.) I suggest you focus on the exercises that use body weight and dumbbells, since adult-size ankle weights probably won't fit her properly. Start with very light weights and progress slowly. I hope you both enjoy these mother-daughter workouts!

Q: I am following the SWSY weight resistance program, and I am also enrolled in a "step" class. While the class is mainly aerobic exercise, we also spend at least 10 minutes a session with weights, bands, or body bars doing weight resistance type exercises. My question is: should I count this as weight training, and give myself rest days around the classes?

A: That depends on the intensity of the strength training. If you're working the muscles to fatigue - to a point where you couldn't continue in good form - then they need a day of rest to recover.

Q: I already have the 5-pound weights. Can I wear two ankle weights on one leg (i.e.: one 5-pound and one 10-pound leg weight? Purchasing two 10-pound weights would be less expensive than two 20-pound weights.

A: There are two possible problems with using two ankle weights on one leg. You might find them uncomfortable; or they might be harder to keep steady than a single ankle weight. Since you already have weights, why don't you try two on one leg to see how they feel. If they're comfortable and stable, then it's fine to use them that way.

From a review of Strong Women Stay Young that appeared in the May/June, 1999 issue of Nutrition in Clinical Care:

"Recommendation of this book is unqualified. . . . the greatest strength of the book lies in its ability to combine theory with practicality. The book's theory is sound. . . However, even the best-designed exercise programs will not succeed if individuals do not adhere to them. Nelson's practical tips for getting motivated and 'staying on track,' as well as her visibly genuine concern for improving women's health, will inspire many readers to adopt strength training as a way of life."

Here's one of the inspiring letters we've received recently. If you enjoy reading it, check out the collection of reader mail on our Web site and see back issues of the newsletter.

"I'm 48 years old. In March my doctor recommended your book to me. Before I began strength training, my arm would get tired when I washed my hair or even brushed my teeth. I had to 'shoulder' my way through most swinging doors - my hand had NO strength, and my entire arm was going the same way. I was miserable, tired all the time, and just felt elderly, to tell you the truth.

I am just amazed at what I can do after three months. I have no trouble with much of anything any more. I'm up to 8-pound weights for triceps and 10 pounds for biceps. I've gained a ton of muscle but I weigh a little less, so I know I've lost fat. I can pick up my 18-month-old grandniece with EASE, and she's a stocky little thing! As Mother's Day presents, my 80 year-old mother got one of your books, and my mother-in-law got another."

Miriam Nelson's Sunday Waffle Breakfast

Sunday brunch is my family's favorite time for entertaining. We usually serve whole-grain waffles with fresh fruit, yogurt and Vermont maple syrup. This is a special treat during the summer, when we can pile on strawberries, raspberries and blueberries. Use your favorite waffle recipe, or buy frozen whole grain waffles. One small waffle counts as one Grain. If you're using frozen waffles, or working with a mix, just remember that a Grain portion is 60-100 calories.

Ingredients

1 small waffle, preferably whole grain (1 Grain)

1/2 cup non-fat plain or vanilla yogurt (1/2 Dairy)

1 cup fresh berries (1 Fruit)

2 teaspoons maple syrup (1 Extra)

Put the waffle on a plate. Spread yogurt over the waffle. Heap berries on top. Drizzle with maple syrup.

Serves 1

Per serving:

1 Grain

1/2 Dairy

1 Fruit

1 Extra