This experiment examined the effect of a moderate dose of caffeine on quadriceps muscle pain during a bout of high-intensity cycling in low- versus high-caffeine-consuming males. College-age men who were low (≤100 mg/day; n = 12) or high (≥400 mg/day; n = 13) habitual caffeine consumers ingested caffeine (5 mg/kg body weight) or a placebo in a counterbalanced order and 1 hr later completed 30 min of cycle ergometry at 75–77% of peak oxygen consumption. Perceptions of quadriceps muscle pain, as well as oxygen consumption, heart rate, and work rate, were recorded during both bouts of exercise. Caffeine ingestion resulted in a statistically significant and moderate reduction in quadriceps muscle-pain-intensity ratings during the 30-min bout of high-intensity cycle ergometry compared with placebo ingestion in both low (d = −0.42) and high (d = −0.55) caffeine consumers. The results suggest that caffeine ingestion is associated with a moderate hypoalgesic effect during high-intensity cycling in college-age men who are low or high habitual caffeine consumers, but future work should consider better defining and differentiating pain and effort when examining the effects of caffeine during acute exercise.
Rachael C. Gliottoni, John R. Meyers, Sigurbjörn Á. Arngrímsson, Steven P. Broglio and Robert W. Motl
Désirée B. Maltais, Claire Gane, Sophie-Krystale Dufour, Dominik Wyss, Laurent J. Bouyer, Bradford J. McFadyen, Karl Zabjek, Jan Andrysek and Julien I.A. Voisin
Little is known about the effects of acute exercise on the cognitive functioning of children with cerebral palsy (CP). Selected cognitive functions were thus measured using a pediatric version of the Stroop test before and after maximal, locomotor based aerobic exercise in 16 independently ambulatory children (8 children with CP), 6–15 years old. Intense exercise had: 1) a significant, large, positive effect on reaction time (RT) for the CP group (preexercise: 892 ± 56.5 ms vs. postexercise: 798 ± 45.6 ms, p < .002, d = 1.87) with a trend for a similar but smaller response for the typically developing (TD) group (preexercise: 855 ± 56.5 ms vs. postexercise: 822 ± 45.6 ms, p < .08, d = 0.59), and 2) a significant, medium, negative effect on the interference effect for the CP group (preexercise: 4.5 ± 2.5%RT vs. postexercise: 13 ± 2.9%RT, p < .04, d = 0.77) with no significant effect for the TD group (preexercise: 7.2 ± 2.5%RT vs. postexercise: 6.9 ± 2.9%RT, p > .4, d = 0.03). Response accuracy was high in both groups pre- and postexercise (>96%). In conclusion, intense exercise impacts cognitive functioning in children with CP, both by increasing processing speed and decreasing executive function.
Jonathan M. Peake
Ascorbic acid or vitamin C is involved in a number of biochemical pathways that are important to exercise metabolism and the health of exercising individuals. This review reports the results of studies investigating the requirement for vitamin C with exercise on the basis of dietary vitamin C intakes, the response to supplementation and alterations in plasma, serum, and leukocyte ascorbic acid concentration following both acute exercise and regular training. The possible physiological significance of changes in ascorbic acid with exercise is also addressed. Exercise generally causes a transient increase in circulating ascorbic acid in the hours following exercise, but a decline below pre-exercise levels occurs in the days after prolonged exercise. These changes could be associated with increased exercise-induced oxidative stress. On the basis of alterations in the concentration of ascorbic acid within the blood, it remains unclear if regular exercise increases the metabolism of vitamin C. However, the similar dietary intakes and responses to supplementation between athletes and nonathletes suggest that regular exercise does not increase the requirement for vitamin C in athletes. Two novel hypotheses are put forward to explain recent findings of attenuated levels of cortisol postexercise following supplementation with high doses of vitamin C.
Brian C. Focht, Deborah J. Knapp, Timothy P. Gavin, Thomas D. Raedeke and Robert C. Hickner
This study examined the psychological responses to an acute bout of aerobic exercise in sedentary older and younger adults. Eighteen young (mean age 24 years) and 15 older adults (mean age 64 years) completed a 20-min bout of stationary cycling at 65% of VO2peak. Affective responses were assessed before, during, and immediately after exercise. Participants’ exercise self-efficacy beliefs were assessed before and immediately after exercise. Both groups reported reduced pleasant feeling states and self-efficacy and increased physical exhaustion in response to acute exercise. Older adults also demonstrated a significant decrease in revitalization during and after cycling. Correlation analyses revealed that self-efficacy was related to feelings of fatigue during exercise and postexercise feelings of energy and fatigue. Both groups reported negative shifts in affect and self-efficacy during and 5 min after cycling. Acute affective and self-efficacy responses might influence one’s motivation to adopt and maintain regular physical activity. The relationship between these acute responses and physical activity behavior across the life span warrants future inquiry.
Rafel Cirer-Sastre, Alejandro Legaz-Arrese, Francisco Corbi, Keith George, Jinlei Nie, Luis Enrique Carranza-García and Joaquim Reverter-Masià
Purpose: The authors evaluated the impact of acute exercise and 24-hour recovery on serum concentration of cardiac troponins T and I (cTnT and cTnI) and N-terminal fragment of the prohormone brain natriuretic peptide (NT-proBNP) in healthy children and adolescents. The authors also determined the proportion of participants exceeding the upper reference limits and acute myocardial infarction cutoff for each assay. Method: Web of Science, SPORTDiscus, MEDLINE, ScienceDirect, and Scopus databases were systematically searched up to November 2017. Studies were screened and quality-assessed; the data was systematically extracted and analyzed. Results: From 751 studies initially identified, 14 met the inclusion criteria for data extraction. All 3 biomarkers were increased significantly after exercise. A decrease from postexercise to 24 hours was noted in cTnT and cTnI, although this decrease was only statistically significant for cTnT. The upper reference limit was exceeded by 76% of participants for cTnT, a 51% for cTnI, and a 13% for NT-proBNP. Furthermore, the cutoff value for acute myocardial infarction was exceeded by 39% for cTnT and a 11% for cTnI. Postexercise peak values of cTnT were associated with duration and intensity (Q (3) = 28.3, P < .001) while NT-proBNP peak values were associated with duration (Q (2) = 11.9, P = .003). Conclusion: Exercise results in the appearance of elevated levels of cTnT, cTnI, and NT-proBNP in children and adolescents. Postexercise elevations of cTnT and NT-proBNP are associated with exercise duration and intensity.
Christine M. Tallon, Ryan G. Simair, Alyssa V. Koziol, Philip N. Ainslie and Alison M. McManus
Purpose: To understand the extent different types of acute exercise influence cerebral blood flow during and following exercise in children. Methods: Eight children (7–11 y; 4 girls) completed 2 conditions: high-intensity interval exercise (HIIE; 6 × 1-min sprints at 90% watt maximum) and moderate-intensity steady-state exercise (MISS; 15 min at 44% watt maximum). Blood velocity in the middle cerebral artery (MCAV) and heart rate were assessed continuously. The partial pressure of end-tidal carbon dioxide and mean arterial pressure were assessed at baseline and following exercise. Results: Percentage of maximum heart rate during HIIE was 82% (4%), compared with 69% (4%) during MISS. MCAV was increased above baseline in MISS after 75 seconds (5.8% [3.9%], P × .004) but was unchanged during HIIE. MCAV was reduced below baseline (−10.7% [4.1%], P × .004) during the sixth sprint of HIIE. In both conditions, MCAV remained below baseline postexercise, but returned to baseline values 30-minute postexercise (P < .001). A postexercise increase in mean arterial pressure was apparent following HIIE and MISS, and persisted 30-minute postexercise. Partial pressure of end-tidal carbon dioxide declined post HIIE (−3.4 mm Hg, P < .05), but not following MISS. Conclusion: These preliminary findings show HIIE and MISS elicit differing intracranial vascular responses; however, research is needed to elucidate the implications and underlying regulatory mechanisms of these responses.
Keith Tolfrey, Julia K. Zakrzewski-Fruer and James Smallcombe
Three publications were selected based on the strength of the research questions, but also because they represent different research designs that are used with varying degrees of frequency in the pediatric literature. The first, a prospective, longitudinal cohort observation study from 7 to 16 years with girls and boys reports an intrinsic reduction in absolute resting energy expenditure after adjustment for lean mass, fat mass, and biological maturity. The authors suggest this could be related to evolutionary energy conservation, but may be problematic now that food energy availability is so abundant. The second focuses on the effect of acute exercise on neutrophil reactive oxygen species production and inflammatory markers in independent groups of healthy boys and men. The authors suggested the boys experienced a “sensitized” neutrophil response stimulated by the exercise bout compared with the men; moreover, the findings provided information necessary to design future trials in this important field. In the final study, a dose-response design was used to examine titrated doses of high intensity interval training on cardiometabolic outcomes in adolescent boys. While the authors were unable to identify a recognizable dose-response relationship, there are several design strengths in this study, which was probably underpowered.
Marcin Baranowski, Jan Górski, Barbara Klapcinska, Zbigniew Waskiewicz and Ewa Sadowska-Krepa
We have previously shown that acute exercise increases the level of sphingosine-1-phosphate (S1P) in plasma and ceramide in erythrocytes of untrained subjects. The aim of the current study was to examine the effect of ultramarathon run on the plasma and erythrocyte levels of the following bioactive sphingolipids: S1P, sphinganine-1-phosphate (SA1P), sphingosine, sphinganine, and ceramide. Blood samples were collected from seven male amateur runners participating in a 48-hr ultramarathon race before the run, after 24 and 48 hr of running, and following 24 and 48 hr of recovery. The sphingolipids were quantified by means of HPLC. Sustained running for 48 hr resulted in a progressive decline in plasma S1P to a level significantly lower than at prerace, and then remained stable over the next 48 hr of recovery. In erythrocytes, S1P content was stable until 24 hr of recovery, then rose abruptly to reach peak values after 48 hr of recovery. The plasma level of SA1P decreased progressively during the competition and remained unchanged over the recovery. In erythrocytes, the level of SA1P increased after 24 hr running and normalized thereafter. The level of ceramide, both in plasma and erythrocytes, was not significantly affected by the ultraendurance run. We speculate that reduction in plasma level of S1P during and after the run reduces its biological actions and might be responsible for some negative side-effects of the ultraendurance effort.
Joel B. Mitchell, James R. Rowe, Meena Shah, James J. Barbee, Austen M Watkins, Chad Stephens and Steve Simmons
To examine the effect of prior exercise on the postprandial lipid response to a high-carbohydrate meal in normal-weight (NW = BMI h25) and overweight (OW = BMI ≥25) women (age 18–25), 10 NW and 10 OW participants completed 2 conditions separated by 1 month. In the morning, the day after control (CT = no exercise) or exercise conditions (EX = 60 min cycling at 60% VO2peak), participants consumed a high-carbohydrate meal (80% CHO, 15% protein, 5% fat; 75 kJ/kg BM) followed by 6 hr of hourly blood sampling. Blood was analyzed for triglycerides (TG), blood glucose (BG), and insulin (IN). TG levels over the 6-hr period were lower in NW than OW (p = .021) and lower in EX than in CT (p = .006). Area under the curve (AUC) for TG was lower in NW than OW (p = .016) and EX than CT (p = .003). There were nonsignificant tendencies for reduced BG over time (p = .053) and AUC (p = .083), and IN AUC was lower in EX than in CT (p = .040) for both groups and lower in NW than in OW (p = .039). Prior exercise improved TG levels after a high-carbohydrate meal in both groups, and OW women demonstrated a greater postprandial lipemic response than NW regardless of condition. There were tendencies for improved glucose removal with prior exercise in NW vs. OW. Acute exercise can improve postprandial TG responses and might also improve postprandial BG and IN after a large meal in NW and OW young women.
Patrick J. O’Connor, Melanie S. Poudevigne, M. Elaine Cress, Robert W. Motl and James F. Clapp III
Describe safety and efficacy of a supervised, low-to-moderate intensity strength training program adopted during pregnancy among women at increased risk for back pain.
32 women adopted strength training twice per week for 12 weeks. Data on musculoskeletal injuries, symptoms, blood pressure, and the absolute external load used for 5 of 6 exercises were obtained during each session. A submaximal lumbar extension endurance exercise test was performed at weeks 5, 10, and 13.
The mean (± SD) exercise session attendance rate was 80.5% (± 11.3%). No musculoskeletal injuries occurred. Potentially adverse symptoms (eg, dizziness) were infrequent (2.1% of sessions). Repeated-measures ANOVA showed large increases in the external load across 12 weeks (all P values < .001) and the percentage increases in external load from weeks 1 to 12 were 36% for leg press, 39% for leg curl, 39% for lat pull down, 41% for lumbar extension and 56% for leg extension. Training was associated with a 14% increase in lumbar endurance. Blood pressure was unchanged following acute exercise sessions and after 12 weeks of exercise training.
The adoption of a supervised, low-to-moderate intensity strength training program during pregnancy can be safe and efficacious for pregnant women.