The International Society of Sports Nutrition has published a new position on the use and effectiveness of caffeine as an ergogenic aid to exercise performance. Jointly authored by a veritable Who’s-Who of sports nutrition experts, the paper reaches the following conclusions:

“1.) Caffeine is effective for enhancing sport performance in trained athletes when consumed in low-to-moderate dosages (~3-6 mg/kg) and overall does not result in further enhancement in performance when consumed in higher dosages (>/= 9 mg/kg). 2.) Caffeine exerts a greater ergogenic effect when consumed in an anhydrous state as compared to coffee. 3.) It has been shown that caffeine can enhance vigilance during bouts of extended exhaustive exercise, as well as periods of sustained sleep deprivation. 4.) Caffeine is ergogenic for sustained maximal endurance exercise, and has been shown to be highly effective for time-trial performance. 5.) Caffeine supplementation is beneficial for high-intensity exercise, including team sports such as soccer and rugby, both of which are categorized by intermittent activity within a period of prolonged duration. 6.) The literature is equivocal when considering the effects of caffeine supplementation on strength-power performance, and additional research in this area is warranted. 7.) The scientific literature does not support caffeine-induced diuresis during exercise, or any harmful change in fluid balance that would negatively affect performance.”

Quercetin is a plant nutrient in the “flavanoid” class that functions as an antioxidant, anti-inflammatory, and stimulus for mitochondrial biogenesis in the human body. Researchers at the University of South Carolina recently investigated whether quercetin supplementation increases maximal aerobic capacity and endurance in untrained subjects. Twelve subjects received either 1000 mg of quercetin daily or placebo for seven days. All subjects performed indoor cycling tests before and after the supplementation period. The whole study design was then repeated with the treatments reversed. On average, the subjects exhibited a 3.9 percent increase in VO2max and a 13.2 percent increase in time to exhaustion after quercetin supplementation.

The authors of the study, which was published in the International Journal of Sports Nutrition and Exercise Metabolism, concluded, “These data suggest that as little as 7 days of quercetin supplementation can increase endurance without exercise training in untrained participants. These benefits of quercetin may have important implications for enhancement of athletic and military performance. This apparent increase in fitness without exercise training may have implications beyond that of performance enhancement to health promotion and disease prevention.”

It is well known that consuming a sports drink before and during longer running races enhances performance. It is also fairly well established that drinking during short races offers no benefit, and may even do more harm than good (by causing hyperventilation or GI distress). But where is the cutoff? What is the shortest race in which drinking is beneficial? We don’t know exactly, and the answer certainly also depends on the individual runner, but a new study by researchers at Loughborough University in England suggests that for moderately high-level runners, drinking a sports drink during a one-hour race is beneficial. Eight trained runners completed one-hour time trials on treadmills on three occasions. They drank flavored water before and during two of the trials and a sports drink during the other. On average, the runners were able to run 2.5 percent farther when they drank the sports drink. Interestingly, most elite male runners capable of running a half marathon under 65 minutes do not drink. They might be better off this way, however, because they are running at a very high percentage of their VO2max and would probably suffer hyperventilation or GI distress if they did try to drink at such high intensities.

Overtraining syndrome is an athletic disorder that involves immune system dysfunction. Elevated levels of cytokines, a class of immune cells, is a known marker of overtraining in athletes. There is some evidence that increased carbohydrate intake may offer some protection against immune system stress during periods of heavy training. Researchers from England’s University of Newcastle recently tested this notion in a group of cyclists and triathletes. The subjects were divided into two groups, one of which was placed on a high-carb diet and the other on a moderate-carb diet for 28 days. At the end of this period all of the subjects performed a challenging test workout on indoor bikes.

The researchers measured the cytokine response to this workout and found no difference in the overall response. However, they did find that the anti-inflammatory cytokine response to exercise was reduced by 30-50 percent in members of the moderate-carb group compared to members of the high-carb group. The researchers concluded that the effect was not enough to warrant the high level of carbohydrate intake used in the study.

Increased training loads increase carbohydrate needs disproportionately compared to fat and protein needs. Thus it is reasonable to speculate that increased carbohydrate intake would help runners handle the stress of increased training periods and perform better in key workouts within such periods.

Brazilian researchers recently tested this idea with a group of 24 male runners. This group was divided into two subgroups, both of which engaged in an eight-day preiod of “overload” training. During this period, one group got 61 percent of daily calories from carbs while the other got 54 percent. At the end of the overload training period both groups performed a three-part workout consisting of a 1000m time trial followed by 10 x 800m at 3000m race pace followed by another 1000m time trial. Yikes!

Members of both groups performed equally well in the first two parts, but members of the high-carbohydrate diet group saw their 1000m time increase by 5.3 percent between the first and second runnings while members of the moderate-carbohydrate diet group saw their times increase by twice that amount. Researchers also observed lower cortisol concentrations and higher post-workout blood glucose concentrations in the high-carb group. These findings suggest that increased carbohydrate intake helped runners to better handle the stress of an overload training period.

Researchers from Appalachian State University recently investigated the effects of independent and combined supplementation with omega-3 essential fatty acids and antioxidant vitamins on exercise-induced oxidative stress (i.e. free radical damage) in the muscles of competitive cyclists. The subjects were divided into four groups. For a period of six weeks, each cyclist received either omega-3, antioxidant vitamins, both, or placebo daily. At the end of the supplementation period, markers of oxidative stress were measured over three days of training. The authors of the study, which was published in Medicine & Science in Sports & Exercise, found that omega-3 supplementation alone significantly increased post-exercise levels of F2-isoprostanes, which are a biomarker of oxidative stress. Supplementation with antioxidant vitamins only slightly reduced the increase associated with omega-3 supplementation. So, while omega-3 fats do a lot of good things in the body, reducing exercise-related oxidative stress appears not to be one of them!

The following as an abstract of a new study published in the journal Medicine & Science in Sports & Exercise: “Purpose: Dietary supplementation with polyphenols, particularly ellagitannins, may attenuate the muscular damage experienced after eccentric exercise, producing delayed-onset muscle soreness. The purpose of this study was to determine whether ellagitannin supplementation from Wonderful variety pomegranate extract (POMx) improved recovery of skeletal muscle strength after eccentric exercise. Methods: Recreationally active males were randomized into a crossover design with either pomegranate extract (POMx) or placebo (PLA), each given during a period of 9 d. To produce delayed-onset muscle soreness, subjects performed two sets of 20 maximal eccentric elbow flexion exercises with one arm. Maximal isometric elbow flexion strength and muscle soreness as well as serum measures of creatine kinase, myoglobin, interleukin 6, and C-reactive protein were made at baseline and 2, 24, 48, 72, and 96 h after exercise. Results: With both treatments, strength was similarly reduced 2 h after exercise (i.e., 72% of baseline), and recovery of strength was incomplete after 96 h (i.e., 91% of baseline). However, strength was significantly higher in POMx compared with that in PLA at 48 h (85.4% ± 2.5% and 78.3% ± 2.6%, P = 0.01) and 72 h (88.9% ± 2.0% and 84.0% ± 2.0%, P = 0.009) after exercise. Serum markers of inflammation and muscle damage did not provide insight regarding possible mechanisms. Conclusions: Supplementation with ellagitannins from pomegranate extract significantly improves recovery of isometric strength 2-3 d after a damaging eccentric exercise.”

The so-called Western diet, with its high fat composition, is the subject of much abuse because of its connection with elevated risk for numerous chronic diseases. But a new study by researchers at the University of California-Riverside suggests that it may increase voluntary exercise, at least in creatures with an innate predisposition toward exercise. The study involved mice, and there’s no telling whether the results seen in these animals would translate to humans. Researchers bred a strain of mice that really liked to run on wheels. In fact, these mice voluntarily ran 2.5-3.0 times as much as normal mice. A bunch of these runner mice and normal mice were given either a high-fat Western diet or a low-fat control diet for two months. Their total caloric intake, weight and adiposity, and running volume were tracked.

The Western diet was found to increase weight and adiposity in both the runner mice and normal mice, but much less so in the runner mice. Mice on the Western diet ate significantly more total calories during the first month of the study, but not the last month. But the most interesting finding was that runner mice on the Western diet voluntarily ran 75 percent more than runner mice on the control diet. The authors of the study, which was published in the International Journal of Obesity, speculated that the high fat content of the diet might have given the mice the endurance needed to run more or it might have somehow increased their psychological motivation to exercise.

Does this mean that human runners are better off on a Western diet? Who knows?

There is evidence that the effectiveness of exercise as a weight-loss method is limited by its effect on the appetite. A new study from the Obesity Research Group looked deeper into the so-called “compensation effect” by investigating the effect of exercise-induced weight loss on appetite-related peptides and the motivation to eat. Twenty-two overweight and sedentary adults engaged in a 12-week supervised exercise program consisting of five sessions of aerobic exercise per week. The subjects were asked not to alter their food intake during the study period.

The subjects lost a significant amount of weight. At the end of the study, they had higher levels of the “hunger hormone” ghrelin and higher levels of self-rated hunger in the fasted state. However, the researchers also found that exercise-induced weight loss had a stronger effect on suppressing ghrelin release and increasing the release of glucagon-like peptide-1, a satiety hormone, after meals. These latter results suggest that exercise-induced weight loss might make meals more satisfying. The authors of the study, which was published in the Journal of Clinical Endocronology and Metabolism, concluded, “Exercise-induced weight loss is associated with physiological and biopsychological changes toward an increased drive to eat in the fasting state. However, this seems to be balanced by an improved satiety response to a meal and improved sensitivity of the appetite control system.”

We know that the body adapts to exercise in a myriad of ways that enhance health. We also know that none of these adaptations is permanent. If a person ceases to exercise, all of those hard-earned adapations reverse themselves. But exercise scientists are now learning that many of the body’s healthful adaptations to exercise are truly transient, lasting less than a day. A daily exercise habit merely gives the appearance of a lasting adaptation. One such adaptation, it appears, is increased insulin sensitivity. While regular exercise does yield a general increase in insulin sensitivity, it also produces a much stronger transient increases that lasts mere hours.

This was shown in a recent study by researchers at McMaster University. The study also found that the strength of the increase depended to a significant degree on what subjects ate after exercise. Low-carbohydrate post-exercise meals boosted insulin sensitivity the most. This makes sense, as increased insulin sensitivity is the body’s protective response to carbohydrate depletion. Exercise depletes carbohydrate, increasing the receptivity of tissues to any carbs taken in after exercise. If only a few carbs are eaten, the body becomes truly alarmed by the situation and insulin sensitivity increases more.