Eric E. Noreen

Motivational Versus Metabolic Effects of Carbohydrates on Self-Control

Self-control is critical for achievement and well-being. However, people’s capacity for self-control is limited and becomes depleted through use. One prominent explanation for this depletion posits that self-control consumes energy through carbohydrate metabolization, which further suggests that ingesting carbohydrates improves self-control. Some evidence has supported this energy model, but because of its broad implications for efforts to improve self-control, we reevaluated the role of carbohydrates in self-control processes. In four experiments, we found that (a) exerting self-control did not increase carbohydrate metabolization, as assessed with highly precise measurements of blood glucose levels under carefully standardized conditions; (b) rinsing one’s mouth with, but not ingesting, carbohydrate solutions immediately bolstered self-control; and (c) carbohydrate rinsing did not increase blood glucose. These findings challenge metabolic explanations for the role of carbohydrates in self-control depletion; we therefore propose an alternative motivational model for these and other previously observed effects of carbohydrates on self-control.

Recovery from a cycling time trial is enhanced with carbohydrate-protein supplementation vs. isoenergetic carbohydrate supplementation

BackgroundIn this study we assessed whether a liquid carbohydrate-protein (C+P) supplement (0.8 g/kg C; 0.4 g/kg P) ingested early during recovery from a cycling time trial could enhance a subsequent 60 min effort on the same day vs. an isoenergetic liquid carbohydrate (CHO) supplement (1.2 g/kg).MethodsTwo hours after a standardized breakfast, 15 trained male cyclists completed a time trial in which they cycled as far as they could in 60 min (AMex) using a Computrainer indoor trainer. Following AMex, subjects ingested either C+P, or CHO at 10, 60 and 120 min, followed by a standardized meal at 4 h post exercise. At 6 h post AMex subjects repeated the time trial (PMex).ResultsThere was a significant reduction in performance for both groups in PMex versus AMex. However, performance and power decreases between PMex and AMex were significantly greater (p ≤ 0.05) with CHO (-1.05 ± 0.44 km and -16.50 ± 6.74 W) vs C+P (-0.30 ± 0.50 km and -3.86 ± 6.47 W). Fat oxidation estimated from RER values was significantly greater (p ≤ 0.05) in the C+P vs CHO during the PMex, despite a higher average workload in the C+P group.ConclusionUnder these experimental conditions, liquid C+P ingestion immediately after exercise increases fat oxidation, increases recovery, and improves subsequent same day, 60 min efforts relative to isoenergetic CHO ingestion.

Effects of supplemental fish oil on resting metabolic rate, body composition, and salivary cortisol in healthy adults

BackgroundTo determine the effects of supplemental fish oil (FO) on resting metabolic rate (RMR), body composition, and cortisol production in healthy adults.MethodsA total of 44 men and women (34 ± 13y, mean+SD) participated in the study. All testing was performed first thing in the morning following an overnight fast. Baseline measurements of RMR were measured using indirect calorimetry using a facemask, and body composition was measured using air displacement plethysmography. Saliva was collected via passive drool and analyzed for cortisol concentration using ELISA. Following baseline testing, subjects were randomly assigned in a double blind manner to one of two groups: 4 g/d of Safflower Oil (SO); or 4 g/d of FO supplying 1,600 mg/d eicosapentaenoic acid (EPA) and 800 mg/d docosahexaenoic acid (DHA). All tests were repeated following 6 wk of treatment. Pre to post differences were analyzed using a treatment X time repeated measures ANOVA, and correlations were analyzed using Pearsons r.ResultsCompared to the SO group, there was a significant increase in fat free mass following treatment with FO (FO = +0.5 ± 0.5 kg, SO = -0.1 ± 1.2 kg, p = 0.03), a significant reduction in fat mass (FO = -0.5 ± 1.3 kg, SO = +0.2 ± 1.2 kg, p = 0.04), and a tendency for a decrease in body fat percentage (FO = -0.4 ± 1.3% body fat, SO = +0. 3 ± 1.5% body fat, p = 0.08). No significant differences were observed for body mass (FO = 0.0 ± 0.9 kg, SO = +0.2 ± 0.8 kg), RMR (FO = +17 ± 260 kcal, SO = -62 ± 184 kcal) or respiratory exchange ratio (FO = -0.02 ± 0.09, SO = +0.02 ± 0.05). There was a tendency for salivary cortisol to decrease in the FO group (FO = -0.064 ± 0.142 μg/dL, SO = +0.016 ± 0.272 μg/dL, p = 0.11). There was a significant correlation in the FO group between change in cortisol and change in fat free mass (r = -0.504, p = 0.02) and fat mass (r = 0.661, p = 0.001).Conclusion6 wk of supplementation with FO significantly increased lean mass and decreased fat mass. These changes were significantly correlated with a reduction in salivary cortisol following FO treatment.

The role of protein and amino acid supplements in the athlete's diet: does type or timing of ingestion matter?

Rather than the age-old debate regarding overall protein and amino acid needs of athletes, this paper focuses on the importance of timing and type of protein and amino acid ingestion relative to both muscle growth and exercise performance. Evidence discussed comes from definitive measurement techniques including net protein balance determinations (for acute studies) or quantification of muscle size or strength (for chronic studies) First, recent data indicate that consuming a small meal of mixed macronutrient composition (or perhaps even a very small quantity of a few indispensable amino acids) immediately before or following strength exercise bouts can alter significantly net protein balance, resulting in greater gains in both muscle mass and strength than observed with training alone. With aerobic exercise, some evidence suggests immediate postexercise (but perhaps not pre-exercise) supplementation is also beneficial. Second, protein type may also be important owing to variable speeds of absorption and availability, differences in amino acid and peptide profiles, unique hormonal response, or positive effects on antioxidant defense. In addition to athletes, many others who desire to regain, maintain, or enhance muscle mass or function, including those with muscle-wasting diseases, astronauts, and all of us as we age, need to ensure that nutrient availability is sufficient during the apparently critical anabolic window of time associated with exercise training sessions. Future studies are needed to fine tune these recommendations.

The Effects of an Acute Dose of Rhodiola rosea on Endurance Exercise Performance

Abstract Noreen, EE, Buckley, JG, Lewis, SL, Brandauer, J, and Stuempfle, KJ. The effects of an acute dose of Rhodiola rosea on endurance exercise performance. J Strength Cond Res 27(3): 839–847, 2013—The purpose of this study was to determine the effects of an acute oral dose of 3 mg·kg−1 of Rhodiola rosea on endurance exercise performance, perceived exertion, mood, and cognitive function. Subjects (n = 18) ingested either R. rosea or a carbohydrate placebo 1 hour before testing in a double-blind, random crossover manner. Exercise testing consisted of a standardized 10-minute warm-up followed by a 6-mile time trial (TT) on a bicycle ergometer. Rating of perceived exertion (RPE) was measured every 5 minutes during the TT using a 10-point Borg scale. Blood lactate concentration, salivary cortisol, and salivary alpha amylase were measured before warm-up, 2 minutes after warm-up, and 2 minutes after TT (n = 15). A Profile of Mood States questionnaire and a Stroop Color Test were completed before warm-up and after TT. Testing was repeated 2–7 days later with the other condition. Rhodiola rosea ingestion significantly decreased heart rate during the standardized warm-up (R. rosea = 136 ± 17 b·min−1; placebo = 140 ± 17 b·min−1; mean ± SD; p = 0.001). Subjects completed the TT significantly faster after R. rosea ingestion (R. rosea = 25.4 ± 2.7 minutes; placebo = 25.8 ± 3.0 minutes; p = 0.037). The mean RPE was lower in the R. rosea trial (R. rosea = 6.0 ± 0.9; placebo = 6.6 ± 1.0; p = 0.04). This difference was even more pronounced when a ratio of the RPE relative to the workload was calculated (R. rosea = 0.048 ± 0.01; placebo = 0.057 ± 0.02; p = 0.007). No other statistically significant differences were observed. Acute R. rosea ingestion decreases heart rate response to submaximal exercise and appears to improve endurance exercise performance by decreasing the perception of effort.

The Effects of Supplemental Fish Oil on Blood Pressure and Morning Cortisol in Normotensive Adults: A Pilot Study

Abstract PURPOSE: To determine the effects of 6wk of supplementation with fish oil (FO) on blood pressure and the morning salivary cortisol concentration in normotensive adults. METHODS: Testing was performed following an overnight fast. Subjects (n=40; 35+/-13y, mean+/-SD) rested supine for 40min, at which time blood pressure and heart rate were measured. Saliva was collected and analyzed for cortisol. Subjects were then randomly assigned to either: 4g/d of Safflower Oil (SO); or 4g/d of FO supplying 1,600mg/d eicosapentaenoic acid and 800mg/d docosahexaenoic acid. Testing was repeated following 6wk of treatment. RESULTS: Compared to SO, there was a significant decrease in systolic blood pressure with FO (SO=1.3+/-5.8 mmHg; FO=-6.8+/-10.2 mmHg; p=0.004), a significant reduction in pulse pressure (SO=0.2+/-7.8 mmHg; FO=-6.4+/-8.8 mmHg; p=0.02), and a tendency for a decrease in mean arterial pressure (SO=1.2+/-5.3 mmHg; FO=-2.5+/-7.3 mmHg; p=0.08). There was a tendency for salivary cortisol to decrease with FO (SO=0.005+/-0.129 µg/dL; FO=-0.068+/-0.148 µg/dL; p=0.072), however, this change was not significantly correlated with the change in systolic blood pressure (r=0.021, p=0.929). CONCLUSION: 6wk of supplementation with FO significantly decreases systolic blood pressure in normotensive adults and this change was not significantly correlated with a reduction in salivary cortisol.

The effects of an acute dose of Rhodiola rosea on exercise performance and cognitive function

Methods A total of 15 recreationally active college women (21.3 ± 0.09 y, 56.1 ± 6.3 kg; mean ± SD) participated in this study. 2–7 d after a familiarization trial subjects ingested in a double blind, random crossover manner, either R. rosea or a carbohydrate placebo 1 h prior to testing. Exercise testing consisted of a 10 minute warm-up, standardized to 80% of the average watts produced during the familiarization trial, followed by a 6 mile simulated indoor time trial on a Velotron electronic bicycle ergometer. Every 5 min during the time trial, subjects rated their level of perceived exertion using a BORG 10 pt scale. A blood sample was taken pre warm-up, 2 minutes post warm-up, and 2 minutes following completion of the time trial, and was analyzed for lactate concentration. Subjects also completed a Profile of Mood States (POMS) questionnaire and a Stroops color test pre-warm up and following the completion of the time trial. Subjects returned to the lab 2–7 d later to repeat the testing with the other condition.

The effect of caffeine ingestion on perception of muscle pain during a sustained submaximal isometric contraction of the quadriceps

Methods A total of 15 low caffeine consuming college aged women (20.5 ± 1.4 y, 66.0 ± 9.0 kg; mean ± SD) participated in this study. 2–7 d after a familiarization trial subjects ingested, in a double blind random crossover manner, either 5 mg/kg caffeine (Caf) or a placebo (P), 1 h prior to performing a 2 min isometric leg extension at 45% of peak torque using visual cues to maintain force production. Every 15 s subjects rated their level of pain using the Borg CR10 pain scale. Subjects returned to the lab 2–7 d later to repeat the testing with the other condition. Data were analyzed using a repeated measures ANOVA with a Tukeys HSD post hoc.

Supplemental Fish Oil Decreases Urinary Excretion of a Marker of Bone Resorption in Healthy Adults

Background Incorporation of fish oil (FO) into the diet of rodents has been shown to result in positive changes in bone health. Currently it is poorly understood if FO has the same effects on bone health in humans. The purpose of this study was to determine the effects of supplemental FO on levels of urinary N-terminal cross-linked telopeptide (NTx), which is a marker of bone breakdown, and how this is related to the morning levels of salivary cortisol and urinary excretion of interleukin 6 (IL-6).