Niacin supplementation impairs exercise performance

2021 ◽  
Author(s):  
Greggory R. Davis ◽  
Arnold G. Nelson
Keyword(s):  
Body Weight ◽  
Resistance Exercise ◽  
Aerobic Exercise ◽  
Exercise Performance ◽  
Respiratory Exchange Ratio ◽  
Time To Exhaustion ◽  
Total Work ◽  
Cycling Exercise ◽  
Exercise Time ◽  
Performance Effects

Abstract. Several pre-workout supplements contain niacin, although the exercise performance effects of niacin are poorly understood. The purpose of the present study was to examine the performance effects of niacin versus caffeine as a pre-workout supplement. Twenty-five untrained males were recruited to complete three identical ramped aerobic cycling exercise trials. Participants were administered caffeine (CA) at 5 mg/kg body weight, 1000 mg niacin (NI), or a methylcelluloce placebo (PL) supplement prior to each trial. NI treatment induced significantly higher respiratory exchange ratio (RER) during exercise compared to the CA treatment, but not the PL treatment (PL=0.87±0.08, NI=0.91±0.08, CA=0.87±0.08; p=0.02). Similarly, exercise time to exhaustion (in minutes) was significantly different between the NI treatment and the CA treatment, but not the PL treatment (PL=27.45±4.47, NI=26.30±4.91, CA=28.76±4.86; p<0.01). Habitual caffeine use (p=0.16), habitual aerobic exercise (p=0.60), and habitual resistance exercise (p=0.10) did not significantly affect RER. Similarly, habitual caffeine use (p=0.72), habitual aerobic exercise (p=0.08), and habitual resistance exercise (p=0.39) did not significantly affect total work performed. The elevated RER and decreased time to exhaustion in the NI treatment suggests limited lipid availability during exercise and impaired exercise performance.

Improvements in exercise performance: effects of carbohydrate feedings and diet

1987 ◽  
Vol 62 (3) ◽  
pp. 983-988 ◽  
Author(s):  
P. D. Neufer ◽  
D. L. Costill ◽  
M. G. Flynn ◽  
J. P. Kirwan ◽  
J. B. Mitchell ◽  
...  
Keyword(s):  
Muscle Glycogen ◽  
Exercise Performance ◽  
Cycle Ergometer ◽  
Serum Glucose ◽  
O2 Consumption ◽  
Total Work ◽  
Vo2 Max ◽  
Fed State ◽  
Performance Effects ◽  
Muscle Glycogen Concentration

In an effort to determine the effects of carbohydrate (CHO) feedings immediately before exercise in both the fasted and fed state, 10 well-trained male cyclists [maximum O2 consumption (VO2 max), 4.35 +/- 0.11 l/min)] performed 45 min of cycling at 77% VO2 max followed by a 15-min performance ride on an isokinetic cycle ergometer. After a 12-h fast, subjects ingested 45 g of liquid carbohydrate (LCHO), solid carbohydrate confectionery bar (SCHO), or placebo (P) 5 min before exercise. An additional trial was performed in which a high-CHO meal (200 g) taken 4 h before exercise was combined with a confectionery bar feeding (M + SCHO) immediately before the activity. At 10 min of exercise, serum glucose values were elevated by 18 and 24% during SCHO and LCHO, respectively, compared with P. At 0 and 45 min no significant differences were observed in muscle glycogen concentration or total use between the four trials. Total work produced during the final 15 min of exercise was significantly greater (P less than 0.05) during M + SCHO (194,735 +/- 9,448 N X m), compared with all other trials and significantly greater (P less than 0.05) during LCHO and SCHO (175,204 +/- 11,780 and 176,013 +/- 10,465 N X m, respectively) than trial P (159,143 +/- 11,407 N X m). These results suggest that, under conditions when CHO stores are less than optimal, exercise performance is enhanced with the ingestion of 45 g of CHO 5 min before 1 h of intense cycling.(ABSTRACT TRUNCATED AT 250 WORDS)

Voluntary fluid intake, hydration status, and aerobic performance of adolescent athletes in the heat

2010 ◽  
Vol 35 (6) ◽  
pp. 834-841 ◽  
Author(s):  
Boguslaw Wilk ◽  
Brian W. Timmons ◽  
Oded Bar-Or
Keyword(s):  
Body Weight ◽  
Oxygen Uptake ◽  
Exercise Performance ◽  
Fluid Intake ◽  
Tap Water ◽  
Peak Oxygen Uptake ◽  
Adolescent Male ◽  
Aerobic Performance ◽  
Hydration Status ◽  
Time To Exhaustion

We determined whether beverage flavoring and composition would stimulate voluntary drink intake, prevent dehydration, and maintain exercise performance in heat-acclimated adolescent males running in the heat. Eight adolescent (age, 13.7 ± 1.1 years) runners (peak oxygen uptake, 59.5 ± 4.0 mL·kg–1·min–1) underwent at least four 80-min exercise heat-acclimation sessions before completing 3 experimental sessions. All sessions were performed at 30 °C and 60%–65% relative humidity. Each experimental session consisted of five 15-min treadmill runs at a speed eliciting 65% peak oxygen uptake, with a 5 min rest prior to each run. Ten minutes after the final run, a time to exhaustion test was performed at a speed eliciting 90% peak oxygen uptake. Counterbalanced experimental sessions were identical, except for fluid intake, which consisted of tap water (W), flavored water (FW), and FW with 6% carbohydrate and 18 mmol·L–1 NaCl (CNa) consumed ad libitum. Fluid intake and body weight were monitored to calculate dehydration. Voluntary fluid intake was similar to fluid losses in W (1032 ± 130 vs. 1340 ± 246 g), FW (1086 ± 86 vs. 1451 ± 253 g), and CNa (1259 ± 119 vs. 1358 ± 234 g). As a result, significant dehydration was avoided in all trials (–0.45% ± 0.68% body weight in W, –0.66% ± 0.50% body weight in FW, and –0.13% ± 0.71% body weight in CNa). Core temperature increased by ~1 °C during exercise, but was not different between trials. Time to exhaustion was not different between trials and averaged 8.8 ± 1.7 min. Under exercise conditions more closely reflecting real-life situations, heat-acclimatized adolescent male runners can appropriately gauge fluid intake regardless of the type of beverage made available, resulting in consistency in exercise performance.

The Combination of Aerobic and Resistance Exercise Induces Weight Loss via the PGC-1α/Irisin/UCP-1 Pathway

2019 ◽  
Vol 9 (10) ◽  
pp. 1388-1394
Author(s):  
Hong Deng ◽  
Wei Zhang ◽  
Dingguo Ruan ◽  
Dezhi Chen ◽  
Xiaoyang Xu ◽  
...  
Keyword(s):  
Weight Loss ◽  
Body Weight ◽  
Resistance Exercise ◽  
Aerobic Exercise ◽  
Human Subjects ◽  
Blood Lipid ◽  
The Body ◽  
Lipid Levels ◽  
Reduced Body ◽  
Blood Lipid Levels

Obesity is a modern disease and the cause is quite complicated. This study explores the effects of aerobic and resistance exercise on weight loss and their relationship with the PGC-1α/Irisin/UCP-1 signaling pathway. First, we selected 52 obese students for aerobic and resistance exercise. Second, we established an obesity rat model, and then subjected them to 12 weeks of aerobic and resistance exercise. The body weights and blood lipid contents of all the subjects were measured, and mRNA and protein expressions were determined via real-time PCR and western blot. In obese students, aerobic exercise and the combination of aerobic and resistance exercise significantly reduced body weight and blood lipid levels. In obese model rats, aerobic and resistance exercise significantly reduced the body weight, blood lipid levels, and increased the PGC-1, Irisin, and UCP-1 levels. Furthermore, the combined effects of aerobic and resistance exercise were similar to those of prolonged aerobic exercise in both human subjects and model rats. The mechanism of weight loss via aerobic and resistance exercise may be related to the PGC-1α/Irisin/UCP-1 pathway, and the combination of aerobic and resistance exercise may be a more suitable weight loss option for obese patients.

scholarly journals PO-221 Effects of different motor functional therapies on cognitive impairment in type 2 diabetes mellitus

2018 ◽  
Vol 1 (5) ◽  
Author(s):  
Yu Zhou
Keyword(s):  
Type 2 Diabetes ◽  
Body Weight ◽  
Cognitive Impairment ◽  
Oxygen Uptake ◽  
Elderly Patients ◽  
Resistance Exercise ◽  
Aerobic Exercise ◽  
Exercise Group ◽  
Control Group

Objective The clinical manifestations of diabetic cognitive dysfunction are decreased visual spatial ability, executive dysfunction, mental activity speed and attention, and decreased abstract logical reasoning. Cognitive dysfunction is irreversible. Timely and accurate assessment and diagnosis, early detection and intervention to delay disease progression are particularly critical. The Cognitive Assessment Scale plays an important role in screening for cognitive dysfunction in diabetes. To observe the effects of motor functional therapy on cognitive impairment and blood glucose, blood lipids, body weight, body composition, and maximal oxygen uptake in patients with type 2 diabetes. Methods A total of 63 elderly patients with type 2 diabetes mellitus in Chengdu community aged ≥65 years and educated for ≥12 years were enrolled in the motor function therapy group according to the simple mental state examination (MMSE) score (diabetes cognitive impairment, MMSE total score) ≥ 20 points, aerobic exercise group, n = 21) and functional function therapy group (diabetes cognitive impairment, MMSE total score ≥ 20 points, resistance exercise group, n = 21). The adult community of diabetes in Chengdu (normal cognitive function) with age ≥ 65 years, education time ≥ 12 years, and MMSE total score ≥ 24 points was used as the control group (n=21). Montreal Cognitive Assessment Scale (MOCA): MOCA is an assessment tool developed by Nasreddine and clinically proven to be used for rapid screening of MCI. There were no statistical differences in baseline data (age, gender, and hypertension incidence) among the 3 groups of patients. The LOTCA scale was used to evaluate the cognitive function of the subjects and to compare between groups. Sixty-three patients with type 2 diabetes were randomly divided into aerobic exercise intensity group (50% VO2max) (n=21), resistance exercise intensity group and control group (n=21). Both the aerobic exercise group and the resistance exercise group underwent a 12-week moderate-intensity exercise three times a week. The resistance middle strength group was trained 2 groups each time, each group was 25 minutes, the group rested for 5 minutes, 55 minutes in total, and the aerobic medium intensity group continued to exercise for 55 minutes. All patients underwent fasting blood glucose (FPG), glycosylated hemoglobin (HbA1c), total cholesterol (TC), triglyceride (TG), low density lipoprotein (LDL), body weight, and fat weight (FW) before and after training. , lean body mass (LBM), maximal oxygen uptake (VO2max) determination; measure the energy expenditure of word movement and the total energy expenditure of the entire exercise process. Results There were no significant differences among the three groups before the test (P>0.05). All the indexes of the medium-intensity resistance exercise group and the medium-intensity aerobic exercise group were significantly different from the control group (P<0.05). After the MOCA score test There was an improvement in the score before the trial, and the total score of LOTCA was significantly different among the three groups. In addition to perceptual sub-items (item identification), the aerobic exercise group and the resistance exercise group LOTCA scale in perceptual sub-projects (incomplete object recognition), visual motion organization and its sub-projects (copying two-dimensional graphics, building blocks) The design and puzzle) project scores were higher than before the test, close to the control group score. The scores of the two groups of exercise therapy in the thinking operation and its sub-projects (Riska organized shape classification, picture arrangement B and geometric reasoning) and attention-focused items were lower than the control group. Compared with the resistance exercise, there was a significant difference in the maximum oxygen uptake between aerobic exercise and resistance exercise (P<0.05). Compared with the total exercise energy consumption in the first 6 weeks, the aerobic exercise group was superior to the resistance exercise group. The total exercise energy expenditure was compared in the last 6 weeks, and the resistance exercise group was superior to the aerobic exercise group. Conclusions Elderly patients with type 2 diabetes may have cognitive impairment earlier. In the absence of differences in exercise, the aerobic exercise group and the resistance exercise group improve cognitive impairment, blood sugar, blood fat, body weight, and body composition in patients with type 2 diabetes. There is no significant difference. Compared with MMSE, LOTCA has the advantage of identifying early cognitive impairment in elderly patients with type 2 diabetes and distinguishing the severity of the damage.  

Intravenous versus Oral Rehydration during a Brief Period: Stress Hormone Responses to Subsequent Exhaustive Exercise in the Heat

2000 ◽  
Vol 10 (4) ◽  
pp. 361-374 ◽  
Author(s):  
Douglas J. Casa ◽  
Carl M. Maresh ◽  
Lawrence E. Armstrong ◽  
Stavros A. Kavouras ◽  
Jorge A. Herrera-Soto ◽  
...  
Keyword(s):  
Body Weight ◽  
Body Fat ◽  
Exhaustive Exercise ◽  
Time To Exhaustion ◽  
Stress Hormone ◽  
Plasma Acth ◽  
Exercise Time ◽  
Oral Rehydration ◽  
Hydration State ◽  
Hormone Responses

The purpose of this study was to determine if intravenous fluid rehydration, versus oral rehydration. during a brief period (20 min) differentially affects plasma ACTH, cortisol, and norepinephrine concentrations during subsequent exhaustive exercise in the heat. Following dehydration (DHY) to −4% of body weight, 8 nonacclimated highly trained males (age = 23.5 ± 1.2 years, V̇O2peak = 61.4±0.8 ml · kg · min−1, % body fat = 13.5±0.6%) cycled to exhaustion at 74% V̇O2peak in 36.8 °C on three different occasions. These included: (a) no fluid (NF), where no fluid was provided during the rehydration period; (b) DRINK, where oral rehydration (0.45% NaCl) was provided equal to 50% of the prior DHY; and (c) IV, where intravenous infusion (0.45% NaCl) was provided equal to 50%’ of the prior DHY. Exercise time to exhaustion was not different p = .07) between the DRINK (34.86 ±4.01) and IV (29.48 ± 3.50) trials, but both were significantly p < .05) longer than the NF (18.95 ± 2.73) trial. No differences (p > .05) were found for any of the hormone measures among trials. The endocrine responses at exhaustion were similar regardless of hydration state and mode of rehydration, but rehydration prolonged the exercise time to exhaustion.

scholarly journals Effect of different exercise trainings on β-cell function, insulin resistance, and osteocalcin levels in overweight men

2021 ◽  
Vol 23 (3) ◽  
pp. 116-123
Author(s):  
Mehdi Rostamizadeh ◽  
Alireza Elmieh ◽  
Farhad Rahmani Nia
Keyword(s):  
Insulin Resistance ◽  
Body Weight ◽  
Resistance Exercise ◽  
Aerobic Exercise ◽  
Cell Function ◽  
Model Assessment ◽  
Homeostasis Model Assessment ◽  
Β Cell ◽  
Supervised Exercise ◽  
Β Cell Function

Background and aims: Many findings have shown the potential relation between osteocalcin (OCN) and regulating energy metabolism. In addition, it has been revealed that physical activity increases OCN levels. Therefore, the present study aimed to investigate the effects of different exercise trainings on β-cell function, insulin resistance, and OCN levels in overweight men. Methods: In this study, 33 overweight, young men [Body mass index (BMI): 29.32±0.75 and age range of 31.50±2.23] were randomly divided into control (n=11), aerobic exercise (n=11), and resistance exercise (n=11) groups. Participants of the exercise group were on the 8-week supervised exercise training program for three sessions per week. Weight, body fat percentage, and BMI were analyzed, and then OCN, insulin, and the homeostasis model assessment of insulin resistance (HOMA-IR) were assessed from fasting blood samples before and after the 8-week exercise program. Finally, data were analyzed by t test and analysis of covariance (ANCOVA). Results: Based on the results, BMI and body weight, insulin, glucose, and HOMA-IR reduced following the exercise (P<0.05) whereas serum OCN significantly increased in aerobic exercise (P=0.001) and resistance exercise (P=0.000) groups. There were no significant changes in β-cell function in aerobic exercise (P=0.512) and resistance exercise (P=0.16) groups. Pearson correlation analysis demonstrated that OCN levels were not correlated with HOMA-IR (P=0.743) and insulin levels (P=0.143). However, OCN was positively associated with the homeostasis model assessment of b-cell function (P=0.014) and glucose (P=0.025). Conclusion: The results of the present study confirmed that aerobic and resistance exercises cause some changes in body weight and BMI, as well as the OCN and HOMA-IR. Nonetheless, changes in OCN levels were not predictors of changes in insulin secretion from pancreatic beta cells.

Endurance and Resistance Respiratory Muscle Training and Aerobic Exercise Performance in Hypobaric Hypoxia

2020 ◽  
Vol 91 (10) ◽  
pp. 776-784
Author(s):  
Courtney E. Wheelock ◽  
Hayden W. Hess ◽  
Blair D. Johnson ◽  
Zachary J. Schlader ◽  
Brian M. Clemency ◽  
...  
Keyword(s):  
Pulmonary Function ◽  
Aerobic Exercise ◽  
Muscle Fatigue ◽  
Exercise Performance ◽  
Hypobaric Hypoxia ◽  
Respiratory Muscle ◽  
Respiratory Muscle Training ◽  
Time To Exhaustion ◽  
Muscle Training ◽  
Before And After

INTRODUCTION: Hypoxia-induced hyperventilation is an effect of acute altitude exposure, which may lead to respiratory muscle fatigue and secondary locomotor muscle fatigue. The purpose of this study was to determine if resistive and/or endurance respiratory muscle training (RRMT and ERMT, respectively) vs. placebo respiratory muscle training (PRMT) improve cycling performance at altitude.METHODS: There were 24 subjects who were assigned to PRMT (N 8), RRMT (N 8), or ERMT (N 8). Subjects cycled to exhaustion in a hypobaric chamber decompressed to 3657 m (12,000 ft) at an intensity of 55% sea level maximal oxygen consumption (Vo2max) before and after respiratory muscle training (RMT). Additionally, subjects completed a Vo2max, pulmonary function, and respiratory endurance test (RET) before and after RMT. All RMT protocols consisted of three 30-min training sessions per week for 4 wk.RESULTS: The RRMT group increased maximum inspiratory (PImax) and expiratory (PEmax) mouth pressure after RMT (PImax: 117.7 11.6 vs. 162.6 20.0; PEmax: 164.0 33.2 vs. 216.5 44.1 cmH2O). The ERMT group increased RET after RMT (5.2 5.2 vs.18.6 16.9 min). RMT did not improve Vo2max in any group. Both RRMT and ERMT groups increased cycling time to exhaustion (RRMT: 35.9 17.2 vs. 45.6 22.2 min and ERMT: 33.8 9.6 vs. 42.9 27.0 min).CONCLUSION: Despite different improvements in pulmonary function, 4 wk of RRMT and ERMT both improved cycle time to exhaustion at altitude.Wheelock CE, Hess HW, Johnson BD, Schlader ZJ, Clemency BM, St. James E, Hostler D. Endurance and resistance respiratory muscle training and aerobic exercise performance in hypobaric hypoxia. Aerosp Med Hum Perform. 2020; 91(10):776784.

Exercise V˙e and physical performance at altitude are not affected by menstrual cycle phase

1999 ◽  
Vol 86 (5) ◽  
pp. 1519-1526 ◽  
Author(s):  
Beth A. Beidleman ◽  
Paul B. Rock ◽  
Stephen R. Muza ◽  
Charles S. Fulco ◽  
Vincent A. Forte ◽  
...  
Keyword(s):  
Menstrual Cycle ◽  
Sea Level ◽  
Exercise Performance ◽  
Minute Ventilation ◽  
Submaximal Exercise ◽  
Cycle Phase ◽  
Time To Exhaustion ◽  
Menstrual Cycle Phase ◽  
Exercise Time ◽  
Midluteal Phase

We hypothesized that progesterone-mediated ventilatory stimulation during the midluteal phase of the menstrual cycle would increase exercise minute ventilation (V˙e; l/min) at sea level (SL) and with acute altitude (AA) exposure but would only increase arterial O2 saturation ([Formula: see text], %) with AA exposure. We further hypothesized that an increased exercise[Formula: see text] with AA exposure would enhance O2 transport and improve both peak O2 uptake (V˙o 2 peak; ml ⋅ kg−1 ⋅ min−1) and submaximal exercise time to exhaustion (Exh; min) in the midluteal phase. Eight female lowlanders [33 ± 3 (mean ± SD) yr, 58 ± 6 kg] completed aV˙o 2 peak and Exh test at 70% of their altitude-specificV˙o 2 peak at SL and with AA exposure to 4,300 m in a hypobaric chamber (446 mmHg) in their early follicular and midluteal phases. Progesterone levels increased ( P < 0.05) ∼20-fold from the early follicular to midluteal phase at SL and AA. PeakV˙e (101 ± 17) and submaximalV˙e (55 ± 9) were not affected by cycle phase or altitude. Submaximal[Formula: see text] did not differ between cycle phases at SL, but it was 3% higher during the midluteal phase with AA exposure. NeitherV˙o 2 peak nor Exh time was affected by cycle phase at SL or AA. We conclude that, despite significantly increased progesterone levels in the midluteal phase, exercise V˙e is not increased at SL or AA. Moreover, neither maximal nor submaximal exercise performance is affected by menstrual cycle phase at SL or AA.

scholarly journals Lifestyle Intervention Involving Calorie Restriction with or without Aerobic Exercise Training Improves Liver Fat in Adults with Visceral Adiposity

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Eiichi Yoshimura ◽  
Hideaki Kumahara ◽  
Takuro Tobina ◽  
Takuro Matsuda ◽  
Makoto Ayabe ◽  
...  
Keyword(s):  
Body Weight ◽  
Exercise Training ◽  
Aerobic Exercise ◽  
Calorie Restriction ◽  
Ideal Body Weight ◽  
Visceral Adiposity ◽  
Aerobic Exercise Training ◽  
Liver Fat ◽  
Exercise Time ◽  
Target Energy

Objective. To evaluate the effect of calorie restriction-induced weight loss with or without aerobic exercise on liver fat.Methods. Thirty-three adults with visceral adiposity were divided into calorie restriction (CR;n = 18) or CR and aerobic exercise (CR + Ex;n = 15) groups. Target energy intake was 25 kcal/kg of ideal body weight. The CR + Ex group had a targeted exercise time of 300 min/wk or more at lactate threshold intensity for 12 weeks.Results. Reductions in body weight (CR,-5.3 ± 0.8 kg; CR + Ex,-5.1 ± 0.7 kg), fat mass (CR,-4.9± 0.9kg; CR + Ex,-4.4 ± 0.6 kg), and visceral fat (CR,-24 ± 5 cm2; CR + Ex,-37 ± 5 cm2) were not statistically different between groups. Liver fat decreased significantly in both groups, with no difference between groups. Change in maximal oxygen uptake was significantly greater in the CR + Ex group than in the CR group (CR,-0.7 ± 0.7 mL/kg/min; CR + Ex,2.9 ± 1.0 mL/kg/min).Conclusion. Both CR and CR + Ex resulted in an improved reduction in liver fat; however, there was no additive effect of exercise training.

Postactivation potentiation attenuates resistance exercise performance decrements following aerobic exercise in trained men

2020 ◽  
Vol 60 (3) ◽  
Author(s):  
Marcelo Conrado de Freitas ◽  
Valéria L. Panissa ◽  
Jason M. Cholewa ◽  
Emerson Franchini ◽  
Luís A. Gobbo ◽  
...  
Keyword(s):  
Resistance Exercise ◽  
Aerobic Exercise ◽  
Exercise Performance ◽  
Postactivation Potentiation
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