Time for a pop quiz, Cornellians:
1. What causes the characteristic soreness that develops 24 to 48 hours after hard exercise?
b.) Microtrauma to muscle.
c.) Working out too hard.
2. You will get fatter from:
a.) Taking in more sugar than your body can use.
b.) Taking in too much diet soda.
c.) Taking in more than the recommended amount of fat.
3. Drinking diet soda:
a.) Is one way most people can improve their health.
b.) Is dangerous because of the fake sweeteners.
c.) Is unhealthy because of the carbonation.
4. One way to raise HDLs (good cholesterol) is:
a.) Drinking one Miller light each day.
b.) Eating more vegetables.
c.) HDLs cannot be improved.
5. Before exercising, you should:
a.) Stretch intensely.
b.) Adequately warm up.
6. When weightlifting, most people will benefit most from:
a.) One set of 8-12 reps, to fatigue.
b.) Three sets of 8-12 reps.
c.) Three sets of 5.
7. Which person is most likely to develop type 2 diabetes mellitus?
a.) Jim, who is 35 pounds overweight.
b.) Steve, who is ideal weight, but eats a lot of simple sugar.
c.) Weight and diet have nothing to do with diabetes.
If you answered: 1.B, 2.A, 3.A, 4.A, 5.B, 6.A, 7.A then read no further; you’ve managed to learn the truth about many popular myths! Otherwise, enjoy:
Question 1 (B): For many years coaches blamed lactate for causing soreness. We now know that not only does it not cause soreness, but it is a critical metabolic substrate that most tissues in the body will use (similar to glucose). In fact, even in moderate exercise, whole body “flux” of lactate exceeds glucose flux! Further, even in events that generate the highest lactate levels (“all-out” for 60-90 seconds), blood lactate levels are back to normal within two hours. Soreness appears to be more related to microtrauma to muscles. Also, it appears that while soreness is not a prerequisite for improvements while training, the inflammatory response to some microtrauma does appear to potentiate the muscle-building response.
Question 2 (A): Gaining fat is a simple matter of taking in more calories than your body can use. While fats do have more calories per gram, most people make the mistake of taking in too much simple sugar. When you take in an excess of simple sugar your body turns it into fat and stores it; through evolution this has been quite advantageous! In fact, while not recommended, you could eat a much higher than recommended percentage of fats and lose weight; total body weight is a function of the calories taken in versus the calories expended. If desired (NOT recommended), you could lose weight while eating snack cakes and McDonalds! Diet soda has no calories.
Question 3 (A): Artificial sweeteners have gotten a bad reputation throughout the years, but the science is very clear: they are safe in doses we consume. In some of the studies that initially caused concern, amounts of fake sweetener that caused problems in rats or mice were of the amount that no person could ingest if they wanted to. Keep in mind that many things in our diet are quiet harmful when taken in large amounts (e.g. sodium, water). One of the easiest ways to lose weight is to replace regular sodas with diet sodas. It should be noted that while “cola” drinkers have been associated with lower bone mineral density in some studies, no study that I know of has shown this to be true for “diet sodas” per se.
Question 4 (A): Although eating more vegetables is usually a good idea, the way to improve HDLs is through aerobic exercise or one glass of alcohol a day. While many associate a glass of red wine per day as beneficial, many forget that the effect on HDLs is due to the alcohol itself — the original study actually produced the improvement with beer, wine, and even vodka! Please take note that drinking more than 1 glass per day does very little if anything for HDLs and is associated with other side effects that can be harmful to your health.
Question 5 (B): Current research indicates that it is important to warm up before any strenuous exercise. Before very dynamic exercise, a warm-up followed by a stretch is probably best. Before lower intensity exercise, it is recommended you stretch after exercising. In fact, you should avoid stretching a muscle that is not warmed up, as this could damage the muscle. For an adequate warm-up, start slowly and be sure to eventually take joints through the full range of motion that they will be exposed to during the activity to come.
Question 6 (A): The American College of Sports Medicine (ACSM), the leading community on exercise science, currently recommends one set of 8-12 reps, to fatigue after an adequate warm-up, 2-3 days/week. It has been demonstrated that while improvements are greater when doing 3 sets instead of 1, it is only marginally better than doing one set of 8-12 reps (on the order of 3-5 percent). However, the improvements seen between doing no weight lifting and lifting 2-3 times a week, 8-12 reps to fatigue, are on the order of 20 to 30 percent. As you can see, you would be spending 3 times the amount of time for an improvement that only a professional athlete would notice. We also know that people are much more likely to stick to a training regime if it lasts 45 minutes (1 set), instead of over 2 hours (3 sets)!
Question 7 (A): Many mistakenly think that eating high amounts of simple sugar causes type 2 diabetes mellitus (T2DM). While the exact etiology of T2DM is still being investigated, we do know that it is highly correlated with being overweight and obese, and not with eating simple sugars per se. In fact, many high level athletes eat remarkable amounts of simple sugars to fuel their bodies, and are at extremely low risk for developing T2DM!
Now take a break from the books and go exercise!
Matthew L. Goodwin is medical student at Weill Cornell in New York City. He completed his undergraduate degree in Exercise Science at Furman University, Masters in Education at Furman, and his PhD in Physiology of Exercise in L. Bruce Gladden’s lab at Auburn University (studying muscle metabolism and lactate physiology). He can be reached at MLG2008@med.cornell.edu. What’s Up, Doc? appears alternate Friday’s this semester.
Original Author: Matthew L. Goodwin